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# Oracle ODBC Driver Help

Version 12.1

# Using the Oracle ODBC Driver

This Oracle ODBC Driver information contains the following sections:

- About Oracle ODBC Driver

- For All Users

- For Advanced Users

- For Programmers

- Glossary

- Acknowledgements

## About Oracle ODBC Driver

What is ODBC?

Open Database Connectivity (ODBC) provides a standard interface that allows one application to access many different data sources. The application's source code does not have to be recompiled for each data source. A database driver links the application to a specific data source. A database driver is a dynamic-link library that an application can invoke on demand to gain access to a particular data source. Therefore, the application can access any data source for which a database driver exists.

The ODBC interface defines the following:

- A library of ODBC function calls that allows an application to connect to a data source, execute SQL statements, and retrieve results.

- SQL syntax based on the SQL-99 specification.

- A standard set of error codes.

- A standard way to connect to and log in to a data source.

- A standard representation for data types.

Figure 1-1 shows the components of the ODBC model. The model begins with an ODBC application making a call to the Driver Manager through the ODBC API. The Driver Manager can be either the Microsoft Driver Manager or the unixODBC Driver Manager. Still using the ODBC API, the Driver Manager makes a call to the ODBC Driver. The ODBC Driver accesses the database over a network communications link using the database API. Figure 1-1 shows an ODBC application accessing three separate databases.

Figure 1-1 Components of the ODBC Model

Description of "Figure 1-1 Components of the ODBC Model"

Related Topic

What is the Oracle ODBC Driver

## For All Users

- Oracle ODBC Driver

- Configuration Tasks

- Modifying the oraodbc.ini File

- Connecting to a Data Source

- Troubleshooting

### Oracle ODBC Driver

- What is the Oracle ODBC Driver

- New and Changed Features

- Features Not Supported

- Files Created by the Installation

- Driver Conformance Levels

- Known Limitations

#### What is the Oracle ODBC Driver

The Oracle ODBC Driver enables ODBC applications on Microsoft Windows, as well as UNIX platforms like Linux, Solaris, and AIX read and write access to Oracle® databases through the ODBC interface using Oracle Net Services software.

The Oracle ODBC Driver uses the Oracle Call Interface (OCI) client and server software to submit requests to and receive responses from the data source. Oracle Net Services communications protocol is used for communications between the OCI client and the Oracle server.

The Oracle ODBC Driver translates ODBC SQL syntax into syntax that can be used to access the data source. When the results are returned from the data source, the Oracle ODBC Driver translates them back to ODBC SQL syntax.

Figure 1-2 shows the Oracle ODBC Driver architecture as described in the preceding paragraphs.

Figure 1-2 Oracle ODBC Driver Architecture

Description of "Figure 1-2 Oracle ODBC Driver Architecture"

* The Oracle ODBC Resource DLL file (`sqres` `xx``.dll`), where `xx` represents the language abbreviation, contains all pertinent language information; the default resource file used is `sqresus.dll`.

For more information about the OCI client and server software, refer to the OCI documentation.

Related Topics

Configuring the Data Source

Connecting to a Data Source

Driver Conformance Levels

New and Changed Features

Files Created by the Installation

#### New and Changed Features

- New Features for Release 12.1.0.1.0

- New Features for Release 11.2.0.1.0

- New Features for Release 11.1.0.1.0

- New Features for Release 10.1.0.2.0

- Changes for Release 10.1.0.2.0

New Features for Release 12.1.0.1.0

Features of the Oracle ODBC Driver Release 12.1.0.1.0 software for the Microsoft Windows Server 2008, Windows Server 2008 R2, Windows 7, Windows 8, Windows Server 2012, Linux X86-64 (32/64 bit), Sun Solaris SPARC64 (32,64 bit), IBM AIX 5L (32,64 bit), Sun Solaris X64 (32,64 bit), HPUX IA64 (32,64 bit), ZLinux (32,64 bit) operating systems are described as follows:

- Oracle ODBC Driver now supports 32 KB data columns with `VARCHAR2`, `NVARCHAR2` and `RAW` data. See Oracle Database PL/SQL Language Reference and Oracle Database SQL Language Reference for information about creating 32 KB columns.

- New parameters in the `odbc.ini` file or connection level attributes:

  - SQL_TRANSLATE_ERRORS= T/F [Default is F (false)]

    Any migrated third party ODBC application, which is using the Babelfish feature, expects that errors returned by the server to be in their native database format, then users can register their translation of errors with the SQL Translation Profile in Oracle Database running in Babelfish mode. Once error translation is registered, then ODBC application users can enable this option, `SQLTranslateErrors = T`, to receive native errors as per their registration.

    For more information on SQL Translation Framework, see Oracle Database Migration Guide, in particular information about SQL Translation Framework Architecture and Overview, Translation Framework installation and configuration, and migration examples.

  See Table 1-5 for more information.

- Oracle ODBC driver now supports executing a stored procedure, which can return implicit results without using `RefCursor`. This support eases any third party ODBC application, which migrated to Oracle and wants to use this same functionality that was provided by their previous vendors.

  See Oracle Database Migration Guide for more information about implicit results support by Oracle Database.

- Extended support of SQLColAttribute() field identifiers to support Oracle Database auto increment feature. You can use this feature by including Oracle ODBC driver specific header file `sqora.h` in the application. See Oracle Call Interface Programmer's Guide for more information about auto increment:

  - `SQL_COLUMN_AUTO_INCREMENT`

    Starting from Oracle Database Release 12c Release 1 (12.1), Oracle supports auto increment columns so the Oracle ODBC Driver has extended the same support through the existing SQLColAttribute() identifier `SQL_COLUMN_AUTO_INCREMENT`. This property is read only and returns `SQL_TRUE` if the column is auto increment; otherwise, it returns `SQL_FALSE`.

  - `SQL_ORCLATTR_COLUMN_PROP`

    Starting from Oracle Database Release 12c Release 1 (12.1), Oracle ODBC Driver supports a new driver specific field identifier `SQL_ORCLATTR_COLUMN_PROP`, which returns the attributes of the column. This identifier returns `SQLULEN` value, which has all the column properties, shown as follows:

        +-----------------------------------------+
        | 32 |...| 10 | 9 | 8 |......| 3 | 2 | 1  |
        +-----------------------------------------+
                                       |   |   |
                                       |   |   |-> Column is auto-increment?
                                       |   |-> Auto value is always generated?
                                       |-> If generated by default when null?

- ODBC APIs supported in Oracle Database Release 12c Release 1 (12.1)

  - SQLMoreResults()

    Implements ODBC support for implicit results. See Table 1-7 in Implementation of ODBC API Functions and `http://msdn.microsoft.com/en-us/library/ms714673(v=VS.85).aspx` for more information.

New Features for Release 11.2.0.1.0

Features of the Oracle ODBC Driver Release 11.2.0.1.0 software for the Microsoft Windows XP, Microsoft Windows 2003 Server, Microsoft Windows Vista, Linux X86-32 (RHEL AS 4,5), Linux X86-64 (RHEL AS 4,5) (32/64 bit), Sun Solaris SPARC64 (9,10) (32,64 bit), IBM AIX 5L 5.2 (32,64 bit), Linux IA64 (64 bit), Linux on Power (32,64 bit), Sun Solaris X64 (64 bit), Hewlett Packard Itanium (32,64 bit) operating systems are described as follows:

- Prefetching of LONG/ LONG RAW data

  Oracle ODBC driver is enhanced to prefetch `LONG` or `LONG RAW` data to improve performance of ODBC applications. To do this, the maximum size of `LONG` data (`MaxLargeData`) must be set in the registry on Windows (you also need to add the registry key `MaxLargeData` in the DSN), and set this manually in the `odbc.ini` file on UNIX platforms. This enhancement improves the performance of Oracle ODBC driver up to 10 times, depending on the `MaxLargeData` size set by the user. The default value of `MaxLargeData` is 0. The maximum value for `MaxLargeData` that you can set is 64KB (65536 bytes).

  If the value of `MaxLargeData` is set to some value greater than 65536, the data fetched will only be 65536 bytes. If you have `LONG` or `LONG RAW` data in the database that is greater that 65536 bytes, `MaxLargeData` should be set to 0 (the default value), which will result in single row fetch and complete `LONG` data can be fetched. If you pass a buffer size less than the `MaxLargeData` size in non-polling mode, a data truncation error will occur if the `LONG` data size in the database is greater than the buffer size.

- Option for using `OCIDescribeAny()` for fetching metadata

  When an application makes heavy calls to small packaged procedures that return `REF CURSORS`, a performance improvement can be made by forcing the driver to use `OCIDescribeAny()`. To enable this option, set the value of `UseOCIDescribeAny` in `odbc.ini` to `T` (True), default value is `F` (False), on UNIX platforms, and through the registry on Windows.

New Features for Release 11.1.0.1.0

Features of the Oracle ODBC Driver Release 11.1.0.1.0 software for the Windows XP, Linux, Solaris, and AIX operating systems are described as follows:

- Disable Rule Hint (DRH Connect String)

  Added the new connection option, Disable RULE Hint that allows user to specify the option to select whether to use RULE Hint in catalog APIs. The change has been done to increase the performance of ODBC driver for catalog APIs. The default value for the option is `TRUE` which means that RULE Hint will not be used in catalog APIs by default.

- Bind Number As Float (BNF Connect String)

  Added the new connection option, Bind Number As Float. By introducing Column Binding for `NUMBER` Column as `FLOAT` when column contains float data speeds up the query execution that uses bind variables as `FLOAT`.

- Statement Caching

  Added support for OCI statement caching feature that provides and manages a cache of statements for each session. By implementing the support for OCI Statement Caching option, Oracle ODBC Driver will see the increase in performance where user have to parse the same statement multiple times in the same connection. The default value for the statement cache flag is `FALSE`.

New Features for Release 10.1.0.2.0

Features of the Oracle ODBC Driver Release 10.1.0.2.0 software for the Windows 98, Windows 2000, Windows XP, and Windows NT X86 operating systems are described as follows:

- Bind `TIMESTAMP` as `DATE` (BTD Connect String)

  Added the new connection option, Bind `TIMESTAMP` as `DATE`, that allows you to bind the ODBC driver `SQL_TIMESTAMP` data type to the Oracle `DATE` data type instead of to the Oracle `TIMESTAMP` data type (which is the default).

- `MONTHNAME (exp)` Function

  Added support for the `MONTHNAME (exp)` function which returns the name of the month represented by the date expression. For example, 'April'.

- `DAYNAME (exp)` Function

  Added support for the `DAYNAME (exp)` function which returns the name of the day represented by the date expression. For example, 'Tuesday'.

- Instant Client Configuration

  Added support for the Instant Client mode configuration.

Changes for Release 10.1.0.2.0

Changed or deprecated features of the Oracle ODBC Driver Release 10.1.0.2.0 include:

- Disable Microsoft Transaction Server

  Changed the default setting for the Disable Microsoft Transaction Server (MTS) from `FALSE` to `TRUE`. By default, MTS support is disabled.

- Floating Point Data Types

  Changed the mapping of the Oracle data types, `BINARY_FLOAT` and `BINARY_DOUBLE`, to map to the ODBC data types, `SQL_REAL` and `SQL_DOUBLE`, respectively.

- SQLGetData Extensions (GDE Connect String)

  Deprecated the `SQLGetData` Extensions connection in this release. The functionality of this feature is always enabled.

- Force Retrieval of Longs (FRL Connect String)

  Deprecated the Force Retrieval of Longs connection option in this release. The functionality of this feature is always enabled.

- Translation Options Configuration Tab

  Deprecated the Translation Options tab previously found on the Oracle ODBC Driver Configuration dialog box in this release.

- Release Notes

  Renamed the Release Notes file from `ODBCRelnotes.wri` to `ODBCRelnotesUS.htm`.

#### Features Not Supported

The Oracle ODBC Driver does not support the following ODBC 3.0 features:

- Interval data types

- `SQL_C_UBIGINT` and `SQL_C_SBIGINT` C data type identifiers

- Shared connections

- Shared environments

- The `SQL_LOGIN_TIMEOUT` attribute of `SQLSetConnectAttr`

Table 1-1 SQL Functions Not Supported by the Oracle ODBC Driver

String Functions | Numeric Functions | Time, Date, and Interval Functions
--- | --- | ---
`BIT_LENGTH` | `ACOS` | `CURRENT_DATE`
`CHAR_LENGTH` | `ASIN` | `CURRENT_TIME`
`CHARACTER_LENGTH` | `ATAN` | `CURRENT_TIMESTAMP`
`DIFFERENCE` | `ATAN2` | `EXTRACT`
`OCTET_LENGTH` | `COT` | `TIMESTAMPDIFF`
`POSITION` | `DEGREES` |
| `RADIANS` |
| `RAND` |
| `ROUND` |

#### Files Created by the Installation

Table 1-2 Files Installed by the Oracle ODBC Driver Kit

Description | File Name for Windows Installation | File Name for UNIX Installation
--- | --- | ---
Oracle ODBC Database Access DLL | `sqora32.dll` | libsqora.so.12.1
Oracle ODBC Driver Setup DLL | `sqoras32.dll` | None
Oracle ODBC Resource DLL | `sqresus.dll` | None
Oracle ODBC Resource DLL for Japanese | `sqresja.dll` | None
Oracle ODBC Driver message file | `oraodbcus.msb` | `oraodbcus.msb`
Oracle ODBC Driver message file for Japanese | `oraodbcja.msb` | `oraodbcja.msb`
Oracle ODBC Driver release notes | `ODBCRelnotesUS.htm` | `ODBCRelnotesUS.htm`
Oracle ODBC Driver release notes for Japanese | `ODBCRelnotesJA.htm` | `ODBCRelnotesJA.htm`
Oracle ODBC Driver Instant Client Release Notes | `ODBC_IC_Readme_Win.html` | `ODBC_IC_Readme_Unix.html`
Oracle ODBC Driver help file | `sqora.htm` | `sqora.htm`
Oracle ODBC Driver help file for Japanese | `sqora.htm` | `sqora.htm`
Oracle ODBC Driver Instant Client install script | `odbc_install.exe` | `odbc_update_ini.sh`
Oracle ODBC Driver Instant Client un-install script | `odbc_uninstall.exe` | None

Microsoft Driver Manager and Administrator Files

See the Microsoft ODBC 3.52 Software Development Kit and Programmer's Reference for the list of files that are installed with Microsoft's ODBC 3.52 Components.

The Microsoft ODBC components are packages in the Microsoft Data Access Component (MDAC) kit. Oracle ODBC driver on Windows has been tested using MDAC version 2.8. This can be downloaded from `http://www.microsoft.com/download/en/search.aspx?q=ODBC+MDAC`

unixODBC Driver Manager and Administrator Files

See the unixODBC readme and INSTALL files for the list of files that are installed with unixODBC Driver Manager.

The unixODBC Driver Manager can be downloaded from `http://www.unixodbc.org/download.html`

#### Driver Conformance Levels

ODBC defines Conformance Levels for drivers in two areas:

- ODBC application programming interface (API)

- ODBC SQL-99 syntax

The Oracle ODBC Driver supports all core API functionality and a limited set of Level 1 and Level 2 functionality. See API Conformance for more information.

The Oracle ODBC Driver is broadly compatible with the SQL-99 Core specification which is a superset of the SQL-92 Entry Level specification. Applications should call SQLGetInfo with the appropriate information type to retrieve a list of SQL-99 supported features.

#### Known Limitations

The following are not supported by Oracle ODBC driver:

- ODBC ASYNC interface

- Control-C to cancel execution in an application

### Configuration Tasks

- Configuring Oracle Net Services

- Configuring the Data Source

- Oracle ODBC Driver Configuration Dialog Box

#### Configuring Oracle Net Services

Before Configuring the Data Source, you must configure network database services so there is an entry for each TNS Service Name. To do this, use Oracle Net Configuration Assistant (NETCA).

Using NETCA, you can create an entry in the tnsnames.ora file for each TNS Service Name. NETCA is installed when you install Oracle Net Services.

#### Configuring the Data Source

Note: The following configuration steps are for Windows users. Unix users must use the `odbc_update_ini.sh` file to create a Data Source Name (DSN).

After installing the Oracle ODBC Driver and Configuring Oracle Net Services, and before using the Oracle ODBC Driver, you must configure the data source.

Before an application can communicate with the data source, you must provide configuration information. The configuration information informs the Oracle ODBC Driver as to which information you want to access.

The data source consists of the data that you want to access, its associated operating system, database management system, and network platform used to access the database management system. The data source for requests submitted by the Oracle ODBC Driver is an Oracle database and supports transports available under Oracle Net Services.

To configure or add an Oracle data source:

After you have installed the Oracle ODBC Driver, use the ODBC Data Source Administrator to configure or add an Oracle data source for each of your Oracle databases. The Oracle ODBC Driver uses the information you enter when you add the data source to access the data. Follow these steps:

1. From the start menu, select Programs, Administrative Tools, Data Sources (ODBC). A list of installed drivers is displayed.

2. Click Add in the Create New Data Source window and then select the Oracle ODBC Driver in the list of installed drivers.

3. Click Finish. The Oracle ODBC Driver Configuration Dialog Box is displayed. You must enter the Data Source Name and TNS Service Name. You can provide the other information requested in the dialog box, or you can leave the fields blank and provide the information when you run the application.

4. After you have entered the data, click OK or click Return.

You can change or delete a data source at any time. The following subtopics explain how to add, change, or delete a data source.

To modify an Oracle data source:

1. From the start menu, select Programs, Administrative Tools, Data Sources(ODBC).

2. In the ODBC Data Source Administrator dialog box, select the data source from the Data Sources list and click Configure. The Oracle ODBC Driver Configuration dialog box is displayed.

3. In the Oracle ODBC Driver Configuration Dialog Box, modify the option values as necessary and click OK.

To delete an Oracle data source:

1. From the start menu, select Programs, Administrative Tools, Data Sources(ODBC).

2. In the ODBC Data Source Administrator dialog box, select the data source you want to delete from the Data Sources list.

3. Click Remove, and then click Yes to confirm the deletion.

Related Topics

Connecting to an Oracle Data Source

Using the Oracle ODBC Driver for the First Time

#### Oracle ODBC Driver Configuration Dialog Box

Note: The Oracle ODBC Driver Configuration dialog box is available for Microsoft Windows users only.

Figure 1-3 Oracle ODBC Driver Configuration Dialog Box

Description of "Figure 1-3 Oracle ODBC Driver Configuration Dialog Box"

The following list is an explanation of the main setup options and fields found on the Oracle ODBC Driver Configuration dialog box shown in the preceding graphic. The tabs found on the lower half of this dialog box are described in subsequent topics.

- Data Source Name - The name used to identify the data source to ODBC. For example, "odbc-pc". You must enter a Data Source Name.

- Description - A description or comment about the data in the data source. For example, "Hire date, salary history, and current review of all employees." The Description field is optional.

- TNS Service Name - The location of the Oracle database from which the ODBC driver will retrieve data. This is the same name entered in Configuring Oracle Net Services using the Oracle Net Configuration Assistant (NETCA). For more information, see the NETCA documentation and Using the Oracle ODBC Driver for the First Time. The TNS Service Name can be selected from a pull-down list of available TNS names. For example, "ODBC-PC". You must enter a TNS Service Name.

- User ID - The user name of the account on the server used to access the data. For example, "scott". The User ID field is optional.

You must enter the Data Source Name and the TNS Service Name. You can provide the other information requested in the dialog box or you can leave the fields blank and provide the information when you run the application.

In addition to the main setup options previously described, there is a Test Connection button available. The Test Connection button verifies whether the ODBC environment is configured properly by connecting to the database specified by the Data Source Name definition. When you press the Test Connection button, you are prompted for the username and password.

For an explanation of the Options tabs found on the lower half of the Oracle ODBC Driver Configuration dialog box, click any of the following links:

Application Options

Oracle Options

Workarounds Options

SQL Server Migration Options

Application Options

Figure 1-4 The Application Options Tab of the Oracle ODBC Driver Configuration Dialog Box

Description of "Figure 1-4 The Application Options Tab of the Oracle ODBC Driver Configuration Dialog Box"

The following list is an explanation of the fields found on the Application Options tab shown in the preceding graphic:

- Enable Result Sets - Enables the processing of Oracle Result Sets. If Result Sets are not required for your application, Result Set support can be disabled. There is a small performance penalty for procedures called from packages not containing Result Sets. Result Sets are enabled by default.

- Enable Query Timeout - Enables query timeout for SQL queries. By default, the Oracle ODBC Driver supports the `SQL_ATTR_QUERY_TIMEOUT` attribute for the SQLSetStmtAttr function. If this box is not checked, the Oracle ODBC Driver responds with a "not capable" message. Query Timeout is enabled by default.

- Read-Only Connection - Check this box to force read-only access. The default is write access.

- Enable Closing Cursors - Enables closing cursors. By default, closing cursors is disabled (the field is empty), meaning a call to close a cursor does not force the closing of OCI cursors when this behavior is not desired because it can cause an unnecessary performance hit. You should enable closing cursors when it is desirable to force the closing of OCI cursors upon a call to close a cursor.

Note: There is an impact on performance each time a cursor is closed.

- Enable Thread Safety - Thread safety can be disabled for a data source. If thread safety is not required, disabling this option eliminates the overhead of using thread safety. By default, thread safety is enabled.

- Batch Autocommit Mode - By default, commit is executed only if all statements succeed.

- Numeric Settings - Allows you to choose which numeric settings will be used to determine the decimal and group separator characters when receiving and returning numeric data that is bound as strings. This option allows you to choose Oracle NLS settings (the default setting), Microsoft default regional settings (to provide a way to mirror the Oracle OLE DB driver's behavior for greater interoperability), or US numeric settings (which are necessary when using MS Access or DAO (Database Access Objects) in non-US environments).

The main configuration setup options are described in the Oracle ODBC Driver Configuration Dialog Box topic.

Oracle Options

Figure 1-5 The Oracle Options Tab of the Oracle ODBC Driver Configuration Dialog Box

Description of "Figure 1-5 The Oracle Options Tab of the Oracle ODBC Driver Configuration Dialog Box"

The following list is an explanation of the fields found on the Oracle Options tab shown in the preceding graphic:

- Fetch Buffer Size - The amount of memory used to determine how many rows of data the ODBC Driver will pre-fetch at a time from an Oracle database regardless of the number of rows the application program requests in a single query. However, the number of pre-fetched rows depends on the width and number of columns specified in a single query. Applications that typically fetch fewer than 20 rows of data at a time will see an improvement in response time, particularly over slow network connections or to heavily loaded servers. Setting this too high can actually make response time worse or consume large amounts of memory.

Note: When `LONG` and LOB data types are present, the number of rows pre-fetched by the ODBC Driver is not determined by the Fetch Buffer Size. The inclusion of the `LONG` and LOB data types minimizes the performance improvement and could result in excessive memory use. The ODBC Driver will disregard the Fetch Buffer Size and only pre-fetch a set number of rows in the presence of the `LONG` and LOB data types.

- Enable LOBs - Enables the writing of Oracle LOBs. If writing Oracle LOBs is not required for your application, LOB support can be disabled. There is a small performance penalty for insert and update statements when LOBs are enabled. LOB writing is enabled by default but disabled for Oracle databases that do not support the LOB data type.

- Enable Statement Caching - Enables statement caching feature, which will increase the performance of parsing the query, in case the user has to parse the same text of query and related parameters multiple times. The default is disabled.

- Cache Buffer Size - The statement cache has a maximum size (number of statements) that can be modified by an attribute on the service context, `OCI_ATTR_STMTCACHESIZE`. The default cache buffer size is 20 that get used only if statement caching option is enabled. Setting cache buffer size to 0 will disable statement caching feature.

- Max Token Size - Sets the token size to the nearest multiple of 1 KB (1024 bytes) beginning at 4 KB (4096 bytes). The default size is 8 KB (8192 bytes). The maximum value that can be set is 128 KB (131068 bytes).

- Translate ORA errors - Any migrated third party ODBC application, which is using the Babelfish feature, expects that errors returned by the server to be in their native database format, then users can enable this option to receive native errors based on the error translation registered with SQL Translation Profile.

- Convert Empty String - Any third party ODBC application that is migrated to Oracle Database requires handling empty string data (Oracle Database does not handle empty string data in table columns), then they can enable this option so that the application can insert empty string data or retrieve empty string data.

  Note: This feature is not implemented for release 12.1.

The Failover area of the Oracle Options tab contains the following fields:

- Enable Failover - Enables Oracle Fail Safe and Oracle Parallel Server failover retry. This option in an enhancement to the failover capabilities of Oracle Fail Safe and Oracle Parallel Server. Enable this option to configure additional failover retries. The default is enabled.

- Retry - The number of times the connection failover will be attempted. The default is 10 attempts.

- Delay - The number of seconds to delay between failover attempts. The default is 10 seconds.

Note: See the Oracle Fail Safe and Oracle Parallel Server documentation on how to set up and use both of these products.

The main configuration setup options are described in the Oracle ODBC Driver Configuration Dialog Box topic.

Workarounds Options

Figure 1-6 The Workarounds Options Tab of the Oracle ODBC Driver Configuration Dialog Box

Description of "Figure 1-6 The Workarounds Options Tab of the Oracle ODBC Driver Configuration Dialog Box"

The following list is an explanation of the fields found on the Workarounds Options tab shown in the preceding graphic:

- Bind TIMESTAMP as DATE - Check this box to force the Oracle ODBC Driver to bind `SQL_TIMESTAMP` parameters as the Oracle `DATE` type instead of as the Oracle `TIMESTAMP` type (the default). For more information, see Implementation of Data Types (Advanced).

- Force SQL_WCHAR Support - Check this box to enable SQLDescribeCol, SQLColumns, and SQLProcedureColumns to unconditionally return the data type of `SQL_WCHAR` for `SQL_CHAR` columns; `SQL_WVARCHAR` for `SQL_VARCHAR` columns; and `SQL_WLONGVARCHAR` for `SQL_LONGVARCHAR` columns. This feature enables Unicode support in applications that rely on the results of these ODBC calls (for example, ADO). This support is disabled by default.

- Disable Microsoft Transaction Server - Clear the check in this box to enable Microsoft Transaction Server (MTS) support. By default, MTS support is disabled.

- Set Metadata Id Default to SQL_TRUE - Check this box to change the default value of the `SQL_ATTR_METADATA_ID` connection and statement attribute at connection time to be `SQL_TRUE`. Under normal circumstances, `SQL_ATTR_METADATA_ID` would default to `SQL_FALSE`. ODBC calls made by the application to specifically change the value of the attribute after connection time will be unaffected by this option and will complete their functions as expected. By default, this option is off. The Implementation of ODBC API Functions topic provides some additional information about the `SQL_ATTR_METADATA_ID` attribute.

- Pre-fetch size for LONG column data - Set this value to prefetch `LONG` or `LONG RAW` data to improve performance of ODBC applications. This enhancement improves the performance of Oracle ODBC driver up to 10 times, depending on the pre-fetch size set by the user. The default value is 0. The maximum value that you can set is 64KB (65536 bytes).

  If the value of pre-fetch size is set to some value greater than 65536, the data fetched will only be 65536 bytes. If you have `LONG` or `LONG RAW` data in the database that is greater that 65536 bytes, the pre-fetch size should be set to 0 (the default value), which will result in single row fetch and complete `LONG` data can be fetched. If you pass a buffer size less than the pre-fetch size in non-polling mode, a data truncation error will occur if the `LONG` data size in the database is greater than the buffer size.

- Disable SQLDescribeParam - If the SQLDescribeParam function is enabled, the `SQL_VARCHAR` data type is returned for all parameters. If the Force SQL_WCHAR Support function is also enabled, the `SQL_WVARCHAR` data type is returned for all parameters. By default, this function is enabled.

- Bind NUMBER as FLOAT - Check this box to force the Oracle ODBC Driver to bind `NUMBER` column containing `FLOAT` data as Float instead of as the Binary Float (the default).

- Disable RULE Hint - Clear the check in this box to enable RULE Hint specified with catalogue queries. By default, RULE Hint option is disabled.

- Use OCIDescribeAny - Check this box to gain a performance improvement by forcing the driver to use `OCIDescribeAny()`when an application makes heavy calls to small packaged procedures that return `REF CURSORS`.

The main configuration setup options are described in the Oracle ODBC Driver Configuration Dialog Box topic.

SQL Server Migration Options

Figure 1-7 The SQL Server Migration Options Tab of the Oracle ODBC Driver Configuration Dialog Box

Description of "Figure 1-7 The SQL Server Migration Options Tab of the Oracle ODBC Driver Configuration Dialog Box"

The following list is an explanation of the fields found on the SQL Server Migration Options tab shown in the preceding graphic:

- EXEC Syntax Enabled - enables support for SQL Server EXEC syntax. A procedure (or function) call specified in an EXEC statement is translated to its equivalent Oracle procedure (or function) call before being processed by an Oracle database server. By default this option is disabled.

- Schema - the translated Oracle procedure (or function) is assumed to be defined in the user's default schema. However, if all procedures (or functions) from the same SQL Server database are migrated to the same Oracle schema with their database name as the schema name, this field should be set to database. By the same token, this field should be set to owner if all procedures (or functions) owned by the same SQL Server user are defined in the same Oracle schema. This field is empty by default.

The main configuration setup options are described in the Oracle ODBC Driver Configuration Dialog Box topic.

### Modifying the oraodbc.ini File

- Reducing Lock Timeout

#### Reducing Lock Timeout

An Oracle server waits indefinitely for lock conflicts between transactions to be resolved. You can limit the amount of time that an Oracle server waits for locks to be resolved by setting the Oracle ODBC Driver's `LockTimeOut` entry in the `oraodbc.ini` file. The value you enter for the `LockTimeOut` parameter is the number of seconds after which an Oracle server will time out if it cannot obtain the requested locks. In the following example, the Oracle server will time out after 60 seconds:

    [Oracle ODBC Driver Common]
    LockTimeOut=60

### Connecting to a Data Source

- Connecting to an Oracle Data Source

#### Connecting to an Oracle Data Source

To connect to a Data Source, the Oracle ODBC Driver requires that the OCI client software be installed on your computer and the corresponding listener be running on the Oracle server. Oracle Net Services for Windows is a Dynamic Linked Library (DLL) based application. For more information about Oracle Net Services, see the Oracle Net Services documentation.

As part of the connection process, an application can prompt you for information. If an application prompts you for information about an Oracle data source, do the following:

1. In the TNS Service Name box, enter the name of the TNS service.

2. In the User Name box, enter the name you use to access an Oracle Database.

3. In the Password box, enter the password you use to access an Oracle Database.

4. Click OK.

An application must connect to a data source in order to access the data in it. Different applications connect to data sources at different times. For example, an application might connect to a data source only at your request, or it might connect automatically when it starts. For information about when an application connects to a data source, see the documentation for that application.

For additional information, click any of the following links.

Related Topic for All Users

Configuring the Data Source

Related Topics for Programmers

SQLDriverConnect Implementation

Data Source Configuration Options

### Troubleshooting

- Using the Oracle ODBC Driver for the First Time

- Expired Password

#### Using the Oracle ODBC Driver for the First Time

Note: This information is for Microsoft Windows users only.

The following problems may occur when you use the Oracle ODBC Driver for the first time and attempt to attach to a database or table:

- `OracleHome``/bin` must be in the system path for the Oracle ODBC Driver to function successfully

  This can be verified by typing `PATH` from a command prompt.

- Your machine or server system is missing required software

  Problem: Oracle ODBC Driver fails to work.
  Cause: Either OCI software is not installed on your machine or Oracle database software is not installed on your server system.
  Recommended Action: Install the required OCI software on your client machine or Oracle database software on your server system or both.

- Client/Server connectivity is incorrectly set up on your machine

  Problem: Cannot connect to the server system from your machine.
  Cause: Either the required transport software is not installed or is not configured correctly.
  Recommended Action: As a test, for example when using TCP/IP, make sure that your machine can ping to the server where the Oracle database resides. Use `tnsping.exe` located in the `/orant/bin` or `/Oracle/ora90/bin` directory to ensure connectivity to a specific database service. For example:
  `C:/ORANT/BIN>tnsping database-service-name`

- TNS Service Name does not match the name that was entered in the Oracle Net Configuration Assistant (NETCA)

  Problem: The user is returned an error message about the TNS Service Name while attempting to set up the Oracle ODBC Driver.
  Cause: The TNS Service Name does not match the name entered in NETCA.
  Recommended Action: Change the TNS Service Name in the Oracle ODBC Driver setup window to match the TNS Service Name in NETCA.

  Note: Refer to the pull-down menu on the Datasource Configuration screen to view a list of all valid TNS service names on the system as well as names entered by users.

- User does not have access to the database

  Problem: The user is returned an access denied error message when attempting to gain access to an Oracle database while using the Oracle ODBC Driver.
  Cause: You do not have access to an Oracle database.
  Recommended Action: Ensure the proper privileges are assigned for the user to gain access to the Oracle database.

- System Error: 182 or 193 when trying to create an ODBC DSN

  Problem: You are trying to create a Data Source Name with the ODBC Administrator but, after selecting the Oracle ODBC Driver, you received a System Error 182 or System Error 193.
  Cause: This error is due to a mismatch in the `mfc42.dll` provided by Microsoft.
  Recommended Action: Verified that `OracleHome``/bin` is in your `PATH` and that you have no duplicate `oci.dll` outside the `OracleHome``/bin`. If you still receive the error, copy the `mfc42.dll` from a working machine to the machine with the problem.

- Translator Library could not be loaded system error code 31

  Problem: On Windows with the Oracle ODBC Driver in the Microsoft ODBC Administrator trying to Add or Delete an Oracle ODBC DSN, you get the error "Translator Library could not be loaded System error code 31."
  Cause: In some cases, Windows machines may contain an outdated version of the `mfc42.dll`. Oracle ODBC is built against the newer version of `mfc42.dll` (specifically, version 6.0.8665.0).
  Recommended Action: An outdated version of `mfc42.dll` is causing this error to occur. Installing MDAC 2.5 SP1 does not take care of this problem. You need to obtain a newer version of the `mfc42.dll` (version 6.0.8665.0 or higher) and replace the outdated `mfc42.dll` in the `%``WINNT``%/System32` directory by:
  -- Copying from another machine that works correctly
  -- Contact Microsoft to find out how to obtain the dll

Note: This dll is a Microsoft DLL.

#### Expired Password

This section contains information about expired passwords.

Expired Password Behavior

If you try to connect to the database and your password has expired, you are prompted to change your password. Upon making a successful password change, you will be connected to the database. However, if you try to connect to the database with a `SQLDriverConnect` call with a `SQL_DRIVER_NOPROMPT` parameter value, the Oracle ODBC Driver will not prompt you for the password change. Instead, an error condition results, producing an error message and number that indicates that the password has expired.

## For Advanced Users

- Creating Oracle ODBC Driver TNS Service Names

- SQL Statements

- Data Types

- Implementation of Data Types (Advanced)

- Limitations on Data Types

- Error Messages

### Creating Oracle ODBC Driver TNS Service Names

To create Oracle ODBC Driver TNS Service Names with Oracle Net Services, use the Oracle Net Configuration Assistant (NETCA), which is installed when you install Oracle Net Services. NETCA creates Oracle ODBC Driver TNS Service Name entries in the tnsnames.ora file.

### SQL Statements

The Oracle ODBC Driver is broadly compatible with the SQL-99 Core specification which is a superset of the SQL-92 Entry Level specification. In addition to Oracle's grammar, the vendor-specific escape sequences outlined in Appendix C of the ODBC specifications are also supported. In accordance with the design of ODBC, the Oracle ODBC Driver will pass native SQL syntax to the Oracle database.

Related Topic for Advanced Users

Data Types

Related Topic for Programmers

Implementation of the ODBC SQL Syntax

### Data Types

The Oracle ODBC Driver maps Oracle database data types to ODBC SQL data types.

Note: All conversions in Appendix D of the Microsoft ODBC 3.52 Software Development Kit and Programmer's Reference are supported for the ODBC SQL data types listed from a call to `SQLGetInfo` with the appropriate information type.

Related Topics for Advanced Users

Implementation of Data Types (Advanced)

Limitations on Data Types

SQL Statements

Related Topic for Programmers

Implementation of Data Types (Programming)

### Implementation of Data Types (Advanced)

- DATE and TIMESTAMP

- Floating Point Data Types

DATE and TIMESTAMP

The semantics of Oracle `DATE` and `TIMESTAMP` data types do not correspond exactly with the ODBC data types with the same names. The Oracle `DATE` data type contains both date and time information while the `SQL_DATE` data type contains only date information. The Oracle `TIMESTAMP` data type also contains date and time information, but it has greater precision in fractional seconds. The ODBC Driver reports the data types of both Oracle `DATE` and `TIMESTAMP` columns as `SQL_TIMESTAMP` to prevent information loss. Similarly the ODBC Driver binds `SQL_TIMESTAMP` parameters as Oracle `TIMESTAMP` values.

Floating Point Data Types

When connected to a 10.1 or later Oracle server, the ODBC Driver maps the Oracle floating point data types `BINARY_FLOAT` and `BINARY_DOUBLE` to the ODBC data types `SQL_REAL` and `SQL_DOUBLE`, respectively. In previous releases, `SQL_REAL` and `SQL_DOUBLE` mapped to the generic Oracle numeric data type.

Related Topic

DATE and TIMESTAMP Data Types

### Limitations on Data Types

The Oracle ODBC Driver and the Oracle database impose limitations on data types. Table 1-3 describes these limitations.

Table 1-3 Limitations Imposed on Data Types by the Oracle ODBC Driver and Oracle Database

Limited Data Type | Description
--- | ---
Literals | Oracle database limits literals in SQL statements to 4,000 bytes.
SQL_LONGVARCHAR and SQL_WLONGVARCHAR | Oracle's limit for `SQL_LONGVARCHAR` data where the column type is `LONG` is 2,147,483,647 bytes. Oracle's limit for the `SQL_LONGVARCHAR` data where the column type is `CLOB` is 4 gigabytes. The limiting factor is the client workstation memory.
SQL_LONGVARCHAR and SQL_LONGVARBINARY | Oracle database allows only a single long data column per table. The long data types are `SQL_LONGVARCHAR` (`LONG`) and `SQL_LONGVARBINARY` (`LONG RAW`). Oracle recommends you use `CLOB` and `BLOB` columns instead. There is no restriction on the number of `CLOB` and `BLOB` columns in a table.

### Error Messages

When an error occurs, the Oracle ODBC Driver returns the native error number, the `SQLSTATE` (an ODBC error code), and an error message. The driver derives this information both from errors detected by the driver and errors returned by the Oracle server.

Native Error

For errors that occur in the data source, the Oracle ODBC Driver returns the native error returned to it by the Oracle server. When the Oracle ODBC Driver or the Driver Manager detects an error, the Oracle ODBC Driver returns a native error of zero.

SQLSTATE

For errors that occur in the data source, the Oracle ODBC Driver maps the returned native error to the appropriate `SQLSTATE`. When the Oracle ODBC Driver detects an error, it generates the appropriate `SQLSTATE`. When the Driver Manager detects an error, it generates the appropriate `SQLSTATE`.

Error Message

For errors that occur in the data source, the Oracle ODBC Driver returns an error message based on the message returned by the Oracle server. For errors that occur in the Oracle ODBC Driver or the Driver Manager, the Oracle ODBC Driver returns an error message based on the text associated with the `SQLSTATE`.

Error messages have the following format:

    [vendor] [ODBC-component] [data-source] error-message

The prefixes in brackets ( [ ] ) identify the source of the error. Table 1-4 shows the values of these prefixes returned by the Oracle ODBC Driver. When the error occurs in the data source, the [vendor] and [ODBC-component] prefixes identify the vendor and name of the ODBC component that received the error from the data source.

Table 1-4 Error Message Values of Prefixes Returned by the Oracle ODBC Driver

Error Source | Prefix | Value
--- | --- | ---
Driver Manager | [vendor][ODBC-component][data-source] | [Microsoft/unixODBC][ODBC Driver Manager]N/A
Oracle ODBC Driver | [vendor][ODBC-component][data-source] | [ORACLE][ODBC Driver]N/A
Oracle server | [vendor][ODBC-component][data-source] | [ORACLE][ODBC Driver]N/A

For example, if the error message does not contain the [Ora] prefix shown in the following format, the error is an Oracle ODBC Driver error and should be self-explanatory.

    [Oracle][ODBC]Error message text here

If the error message contains the [Ora] prefix shown in the following format, it is not an Oracle ODBC Driver error. Note that although the error message contains the [Ora] prefix, the actual error may be coming from one of several sources.

    [Oracle][ODBC][Ora]Error message text here

If the error message text starts with the following prefix, you can obtain more information about the error in the Oracle server documentation.

    ORA-

Oracle Net Services errors and Trace logging are located under the `ORACLE_HOME``\NETWORK` directory on Windows systems or the `ORACLE_HOME``/NETWORK` directory on UNIX systems where the OCI software is installed and specifically in the log and trace directories respectively. Database logging is located under the `ORACLE_HOME``\RDBMS` directory on Windows systems or the `ORACLE_HOME``/rdbms` directory on UNIX systems where the Oracle server software is installed.

See the Oracle server documentation for more information about server error messages.

## For Programmers

- Format of the Connection String

- SQLDriverConnect Implementation

- Reducing Lock Timeout in a Program

- Linking with odbc32.lib (Windows) or libodbc.so (UNIX)

- Obtaining Information About rowids

- Rowids in a WHERE Clause

- Enabling Result Sets

- Enabling EXEC Syntax

- Enabling Event Notification for Connection Failures in an Oracle RAC Environment

- Using Implicit Results Feature Through ODBC

- Supported Functionality

- Unicode Support

- Performance and Tuning

### Format of the Connection String

Table 1-5 describes keywords that can be included in the connection string argument of the `SQLDriverConnect` function call. Missing keywords will be read from the Administrator entry for the data source. Values specified in the connection string will override those contained in the Administrator entry. See the Microsoft ODBC 3.52 Software Development Kit and Programmer's Reference for more information about the `SQLDriverConnect` function.

Table 1-5 Keywords that Can Be Included in the Connection String Argument of the SQLDriverConnect Function Call

Keyword | Meaning | Comments
--- | --- | ---
DSN | ODBC Data Source Name | User-supplied name.
DBQ | TNS Service Name | User-supplied name.
UID | User ID or User Name | User-supplied name.
PWD | Password | User-supplied password. Specify PWD=; for an empty password.
DBA | Database Attribute | W=write access. R=read-only access.
APA | Applications Attributes | T=Thread Safety Enabled. F=Thread Safety Disabled.
RST | Result Sets | T=Result Sets Enabled. F=Result Sets Disabled.
QTO | Query Timeout Option | T=Query Timeout Enabled. F=Query Timeout Disabled.
CSR | Close Cursor | T=Close Cursor Enabled. F=Close Cursor Disabled.
BNF | Bind `NUMBER` as `FLOAT` | T=Bind `NUMBER` as `FLOAT`. F=Bind `NUMBER` as `NUMBER`.
DRH | Disable Rule Hint | T=Disable Rule Hint. F=Enable Rule Hint.
BAM | Batch Autocommit Mode | IfAllSuccessful=Commit only if all statements are successful (old behavior). UpToFirstFailure=Commit up to first failing statement (V7 ODBC behavior). AllSuccessful=Commit all successful statements (only when connected to an Oracle database; against other databases, same behavior as V7).
FBS | Fetch Buffer Size | User-supplied numeric value (specify a value in bytes of 0 or greater). The default is 60,000 bytes.
FEN | Failover | T=Failover Enabled. F=Failover Disabled.
FRC | Failover Retry Count | User-supplied numeric value. The default is 10.
FDL | Failover Delay | User-supplied numeric value. The default is 10.
LOB | LOB Writes | T=LOBs Enabled. F=LOBs Disabled.
MTS | Microsoft Transaction Server Support | T=Disabled. F=Enabled.
FWC | Force `SQL_WCHAR` Support | T=Force `SQL_WCHAR` Enabled. F=Force `SQL_WCHAR` Disabled.
EXC | EXEC Syntax | T=EXEC Syntax Enabled. F=EXEC Syntax Disabled.
XSM | Schema Field | Default=Default. Database=Database Name. Owner=Owner Name.
MDI | Set Metadata ID Default | T=`SQL_ATTR_METADATA_ID` defaults to `SQL_TRUE`. F=`SQL_ATTR_METADATA_ID` defaults to `SQL_FALSE`.
DPM | Disable `SQLDescribeParam` | T=`SQLDescribeParam` Disabled. F=`SQLDescribeParam` Enabled.
BTD | Bind `TIMESTAMP` as `DATE` | T=Bind `SQL_TIMESTAMP` as Oracle `DATE` F=Bind `SQL_TIMESTAMP` as Oracle `TIMESTAMP`
NUM | Numeric Settings | NLS=Use Oracle NLS numeric settings (to determine the decimal and group separator).MS=Use Microsoft regional settings.US=Use US settings.
ODA | Use `OCIDescribeAny( )` | T= Use `OCIDescribeAny( )` call to gain performance improvement when application makes heavy calls to small packaged procedures that return `REF CURSORS`. F= Do not use `OCIDescribeAny( )`. By default, use `OCIDescribeAny( )` value is `FALSE`.
STE | SQL Translate ORA Errors Specifies whether or not the Oracle ODBC Driver is to translate the Oracle error codes | T=Translate ORA errors. F=Do not translate any ORA error. By default, `SQLTranslateErrors` is set to `FALSE`.
TSZ | Token Size | User-supplied numeric value. Sets the token size to the nearest multiple of 1 KB (1024 bytes) beginning at 4 KB (4096 bytes). The default size is 8 KB (8192 bytes). The maximum value that can be set is 128 KB (131068 bytes).

If the following keyword is specified in the connection string, the Oracle ODBC Driver will not read any values defined from the Administrator:

    DRIVER={Oracle ODBC Driver}

Examples of valid connection strings are:

    1) DSN=Personnel;UID=Kotzwinkle;PWD=;2) DRIVER={Oracle ODBC Driver};UID=Kotzwinkle;PWD=whatever;DBQ=instl_alias;DBA=W;

For additional information, click any of the following links.

Related Topic for All Users

Connecting to an Oracle Data Source

Related Topic for Programmers

SQLDriverConnect Implementation

### SQLDriverConnect Implementation

Table 1-6 Keywords Required by the SQLDriverConnect Connection String

Keyword | Description
--- | ---
DSN | The name of the data source.
DBQ | The TNS Service Name. See Creating Oracle ODBC Driver TNS Service Names. For more information, see the Oracle Net Services documentation.
UID | The user login ID or user name.
PWD | The user-specified password.

### Reducing Lock Timeout in a Program

The Oracle server waits indefinitely for lock conflicts between transactions to be resolved. You can limit the amount of time that the Oracle server waits for locks to be resolved by calling the ODBC `SQLSetConnectAttr` function before connecting to the data source. Specify a nonzero value for the `SQL_ATTR_QUERY_TIMEOUT` attribute in the ODBC `SQLSetStmtAttr function`.

If you specify a lock timeout value using the ODBC `SQLSetConnectAttr` function, it overrides any value specified in the oraodbc.ini file. Refer to Reducing Lock Timeout for more information on specifying a value in the `oraodbc.ini` file.

### Linking with odbc32.lib (Windows) or libodbc.so (UNIX)

For Windows platforms, when you link your program, you must link it with the import library `odbc32.lib`.

For UNIX platforms, an ODBC application should be linked to `libodbc.so`.

### Obtaining Information About rowids

The ODBC `SQLSpecialColumns` function returns information about the columns in a table. When used with the Oracle ODBC Driver, it returns information about the Oracle rowids associated with an Oracle table.

### Rowids in a WHERE Clause

Rowids may be used in the `WHERE` clause of an SQL statement. However, the rowid value must be presented in a parameter marker.

### Enabling Result Sets

Oracle reference cursors (Result Sets) allow an application to retrieve data using stored procedures and stored functions. The following information identifies how to use reference cursors to enable Result Sets through ODBC.

- The ODBC syntax for calling stored procedures must be used. Native PL/SQL is not supported through ODBC. The following identifies how to call the procedure or function without a package and within a package. The package name in this case is RSET.

      Procedure call:
      {CALL Example1(?)}
      {CALL RSET.Example1(?)}
      Function Call:
      {? = CALL Example1(?)}
      {? = CALL RSET.Example1(?)}

- The PL/SQL reference cursor parameters are omitted when calling the procedure. For example, assume procedure Example2 is defined to have four parameters. Parameters 1 and 3 are reference cursor parameters and parameters 2 and 4 are character strings. The call is specified as:

      {CALL RSET.Example2("Literal 1", "Literal 2")}

The following example application shows how to return a Result Set using the Oracle ODBC Driver:

    /*
    * Sample Application using Oracle reference cursors via ODBC
    *
    * Assumptions:
    *
    * 1) Oracle Sample database is present with data loaded for the EMP table.
    *
    * 2) Two fields are referenced from the EMP table ename and mgr.
    *
    * 3) A data source has been setup to access the sample database.
    *
    *
    * Program Description:
    *
    * Abstract:
    *
    * This program demonstrates how to return result sets using
    * Oracle stored procedures
    *
    * Details:
    *
    * This program:
    * Creates an ODBC connection to the database.
    * Creates a Packaged Procedure containing two result sets.
    * Executes the procedure and retrieves the data from both result sets.
    * Displays the data to the user.
    * Deletes the package then logs the user out of the database.
    *
    *
    * The following is the actual PL/SQL this code generates to
    * create the stored procedures.
    *
    DROP PACKAGE ODBCRefCur;
    CREATE PACKAGE ODBCRefCur AS
    TYPE ename_cur IS REF CURSOR;
    TYPE mgr_cur IS REF CURSOR;
    PROCEDURE EmpCurs(Ename IN OUT ename_cur, Mgr IN OUT mgr_cur, pjob IN VARCHAR2);

    END;
    /
    CREATE PACKAGE BODY ODBCRefCur AS
    PROCEDURE EmpCurs(Ename IN OUT ename_cur, Mgr IN OUT mgr_cur, pjob IN VARCHAR2)
    AS
    BEGIN
    IF NOT Ename%ISOPEN
    THEN
    OPEN Ename for SELECT ename from emp;
    END IF;

    IF NOT Mgr%ISOPEN
    THEN
    OPEN Mgr for SELECT mgr from emp where job = pjob;
    END IF;
    END;
    END;
    /

    *
    * End PL/SQL for Reference Cursor.
    */

    /*
    * Include Files
    */
    #include <windows.h>
    #include <stdio.h>
    #include <sql.h>
    #include <sqlext.h>

    /*
    * Defines
    */
    #define JOB_LEN 9
    #define DATA_LEN 100
    #define SQL_STMT_LEN 500

    /*
    * Procedures
    */
    void DisplayError( SWORD HandleType, SQLHANDLE hHandle, char *Module );

    /*
    * Main Program
    */
    int main()
    {
    SQLHENV hEnv;
    SQLHDBC hDbc;
    SQLHSTMT hStmt;
    SQLRETURN rc;
    char *DefUserName ="scott";
    char *DefPassWord ="tiger";
    SQLCHAR ServerName[DATA_LEN];
    SQLCHAR *pServerName=ServerName;
    SQLCHAR UserName[DATA_LEN];
    SQLCHAR *pUserName=UserName;
    SQLCHAR PassWord[DATA_LEN];
    SQLCHAR *pPassWord=PassWord;
    char Data[DATA_LEN];
    SQLINTEGER DataLen;
    char error[DATA_LEN];
    char *charptr;
    SQLCHAR SqlStmt[SQL_STMT_LEN];
    SQLCHAR *pSqlStmt=SqlStmt;
    char *pSalesMan = "SALESMAN";
    SQLINTEGER sqlnts=SQL_NTS;

    /*
    * Allocate the Environment Handle
    */
    rc = SQLAllocHandle( SQL_HANDLE_ENV, SQL_NULL_HANDLE, &hEnv );
    if (rc != SQL_SUCCESS)
    {
    printf( "Cannot Allocate Environment Handle/n");
    printf( "/nHit Return to Exit/n");
    charptr = gets ((char *)error);
    exit(1);
    }

    /*
    * Set the ODBC Version
    */
    rc = SQLSetEnvAttr( hEnv,
    SQL_ATTR_ODBC_VERSION,
    (void *)SQL_OV_ODBC3,
    0);
    if (rc != SQL_SUCCESS)
    {
    printf( "Cannot Set ODBC Version/n");
    printf( "/nHit Return to Exit/n");
    charptr = gets ((char *)error);
    exit(1);
    }

    /*
    * Allocate the Connection handle
    */
    rc = SQLAllocHandle( SQL_HANDLE_DBC, hEnv, &hDbc );
    if (rc != SQL_SUCCESS)
    {
    printf( "Cannot Allocate Connection Handle/n");
    printf( "/nHit Return to Exit/n");
    charptr = gets ((char *)error);
    exit(1);
    }

    /*
    * Get User Information
    */
    lstrcpy( (char *) pUserName, DefUserName );
    lstrcpy( (char *) pPassWord, DefPassWord );

    /*
    * Data Source name
    */
    printf( "/nEnter the ODBC Data Source Name/n" );
    charptr = gets ((char *) ServerName);

    /*
    * User Name
    */
    printf ( "/nEnter User Name Default [%s]/n", pUserName);
    charptr = gets ((char *) UserName);
    if (*charptr == '/0')
    {
    lstrcpy( (char *) pUserName, (char *) DefUserName );
    }

    /*
    * Password
    */
    printf ( "/nEnter Password Default [%s]/n", pPassWord);
    charptr = gets ((char *)PassWord);
    if (*charptr == '/0')
    {
    lstrcpy( (char *) pPassWord, (char *) DefPassWord );
    }

    /*
    * Connection to the database
    */
    rc = SQLConnect( hDbc,
    pServerName,
    (SQLSMALLINT) lstrlen((char *)pServerName),
    pUserName,
    (SQLSMALLINT) lstrlen((char *)pUserName),
    pPassWord,
    (SQLSMALLINT) lstrlen((char *)pPassWord));
    if (rc != SQL_SUCCESS)
    {
    DisplayError(SQL_HANDLE_DBC, hDbc, "SQLConnect");
    }

    /*
    * Allocate a Statement
    */
    rc = SQLAllocHandle( SQL_HANDLE_STMT, hDbc, &hStmt );
    if (rc != SQL_SUCCESS)
    {
    printf( "Cannot Allocate Statement Handle/n");
    printf( "/nHit Return to Exit/n");
    charptr = gets ((char *)error);
    exit(1);
    }

    /*
    * Drop the Package
    */
    lstrcpy( (char *) pSqlStmt, "DROP PACKAGE ODBCRefCur");
    rc = SQLExecDirect(hStmt, pSqlStmt, lstrlen((char *)pSqlStmt));

    /*
    * Create the Package Header
    */
    lstrcpy( (char *) pSqlStmt, "CREATE PACKAGE ODBCRefCur AS/n");
    lstrcat( (char *) pSqlStmt, " TYPE ename_cur IS REF CURSOR;/n");
    lstrcat( (char *) pSqlStmt, " TYPE mgr_cur IS REF CURSOR;/n/n");
    lstrcat( (char *) pSqlStmt, " PROCEDURE EmpCurs (Ename IN OUT ename_cur,");
    lstrcat( (char *) pSqlStmt, "Mgr IN OUT mgr_cur,pjob IN VARCHAR2);/n/n");
    lstrcat( (char *) pSqlStmt, "END;/n");
    rc = SQLExecDirect(hStmt, pSqlStmt, lstrlen((char *)pSqlStmt));
    if (rc != SQL_SUCCESS)
    {
    DisplayError(SQL_HANDLE_STMT, hStmt, "SQLExecDirect");
    }

    /*
    * Create the Package Body
    */
    lstrcpy( (char *) pSqlStmt, "CREATE PACKAGE BODY ODBCRefCur AS/n");
    lstrcat( (char *) pSqlStmt, " PROCEDURE EmpCurs (Ename IN OUT ename_cur,");
    lstrcat( (char *) pSqlStmt, "Mgr IN OUT mgr_cur, pjob IN VARCHAR2)/n AS/n BEGIN/n");
    lstrcat( (char *) pSqlStmt, " IF NOT Ename%ISOPEN/n THEN/n");
    lstrcat( (char *) pSqlStmt, " OPEN Ename for SELECT ename from emp;/n");
    lstrcat( (char *) pSqlStmt, " END IF;/n/n");
    lstrcat( (char *) pSqlStmt, " IF NOT Mgr%ISOPEN/n THEN/n");
    lstrcat( (char *) pSqlStmt, " OPEN Mgr for SELECT mgr from emp where job = pjob;/n");
    lstrcat( (char *) pSqlStmt, " END IF;/n");
    lstrcat( (char *) pSqlStmt, " END;/n");
    lstrcat( (char *) pSqlStmt, "END;/n");
    rc = SQLExecDirect(hStmt, pSqlStmt, lstrlen((char *)pSqlStmt));
    if (rc != SQL_SUCCESS)
    {
    DisplayError(SQL_HANDLE_STMT, hStmt, "SQLExecDirect");
    }

    /*
    * Bind the Parameter
    */
    rc = SQLBindParameter(hStmt,
    1,
    SQL_PARAM_INPUT,
    SQL_C_CHAR,
    SQL_CHAR,
    JOB_LEN,
    0,
    pSalesMan,
    0,
    &sqlnts);

    /*
    * Call the Store Procedure which executes the Result Sets
    */
    lstrcpy( (char *) pSqlStmt, "{CALL ODBCRefCur.EmpCurs(?)}");
    rc = SQLExecDirect(hStmt, pSqlStmt, lstrlen((char *)pSqlStmt));
    if (rc != SQL_SUCCESS)
    {
    DisplayError(SQL_HANDLE_STMT, hStmt, "SQLExecDirect");
    }

    /*
    * Bind the Data
    */
    rc = SQLBindCol( hStmt,
    1,
    SQL_C_CHAR,
    Data,
    sizeof(Data),
    &DataLen);
    if (rc != SQL_SUCCESS)
    {
    DisplayError(SQL_HANDLE_STMT, hStmt, "SQLBindCol");
    }

    /*
    * Get the data for Result Set 1
    */
    printf( "/nEmployee Names/n/n");
    while ( rc == SQL_SUCCESS )
    {
    rc = SQLFetch( hStmt );
    if ( rc == SQL_SUCCESS )
    {
    printf("%s/n", Data);
    }
    else
    {
    if (rc != SQL_NO_DATA)
    {
    DisplayError(SQL_HANDLE_STMT, hStmt, "SQLFetch");
    }
    }
    }

    printf( "/nFirst Result Set - Hit Return to Continue/n");
    charptr = gets ((char *)error);

    /*
    * Get the Next Result Set
    */
    rc = SQLMoreResults( hStmt );
    if (rc != SQL_SUCCESS)
    {
    DisplayError(SQL_HANDLE_STMT, hStmt, "SQLMoreResults");
    }

    /*
    * Get the data for Result Set 2
    */
    printf( "/nManagers/n/n");
    while ( rc == SQL_SUCCESS )
    {
    rc = SQLFetch( hStmt );
    if ( rc == SQL_SUCCESS )
    {
    printf("%s/n", Data);
    }
    else
    {
    if (rc != SQL_NO_DATA)
    {
    DisplayError(SQL_HANDLE_STMT, hStmt, "SQLFetch");
    }
    }
    }

    printf( "/nSecond Result Set - Hit Return to Continue/n");
    charptr = gets ((char *)error);

    /*
    * Should Be No More Results Sets
    */
    rc = SQLMoreResults( hStmt );
    if (rc != SQL_NO_DATA)
    {
    DisplayError(SQL_HANDLE_STMT, hStmt, "SQLMoreResults");
    }

    /*
    * Drop the Package
    */
    lstrcpy( (char *) pSqlStmt, "DROP PACKAGE ODBCRefCur");
    rc = SQLExecDirect(hStmt, pSqlStmt, lstrlen((char *)pSqlStmt));

    /*
    * Free handles close connections to the database
    */
    SQLFreeHandle( SQL_HANDLE_STMT, hStmt );
    SQLDisconnect( hDbc );
    SQLFreeHandle( SQL_HANDLE_DBC, hDbc );
    SQLFreeHandle( SQL_HANDLE_ENV, hEnv );

    printf( "/nAll Done - Hit Return to Exit/n");
    charptr = gets ((char *)error);
    return(0);
    }

    /*
    * Display Error Messages
    */
    void DisplayError( SWORD HandleType, SQLHANDLE hHandle, char *Module )
    {

    SQLCHAR MessageText[255];
    SQLCHAR SQLState[80];
    SQLRETURN rc=SQL_SUCCESS;
    LONG NativeError;
    SWORD RetLen;
    SQLCHAR error[25];
    char *charptr;

    rc = SQLGetDiagRec(HandleType,
    hHandle,
    1,
    SQLState,
    &NativeError,
    MessageText,
    255,
    &RetLen);

    printf( "Failure Calling %s/n", Module );
    if (rc == SQL_SUCCESS || rc == SQL_SUCCESS_WITH_INFO)
    {
    printf( "/t/t/t State: %s/n", SQLState);
    printf( "/t/t/t Native Error: %d/n", NativeError );
    printf( "/t/t/t Error Message: %s/n", MessageText );
    }

    printf( "/nHit Return to Exit/n");
    charptr = gets ((char *)error);

    exit(1);
    }

### Enabling EXEC Syntax

If the syntax of your SQL Server `EXEC` statement can be readily translated to an equivalent Oracle procedure call without requiring any change to it, the Oracle ODBC Driver can translate it if you enable this option.

The complete name of a SQL Server procedure consists of up to four identifiers:

- server name

- database name

- owner name

- procedure name

The format for the name is:

    [[[server.][database].][owner_name].]procedure_name

During the migration of the SQL Server database to Oracle, the definition of each SQL Server procedure (or function) is converted to its equivalent Oracle syntax and is defined in a schema in Oracle. Migrated procedures are often reorganized (and created in schemas) in one of the three following ways:

- All procedures are migrated to one schema (the default option).

- All procedures defined in one SQL Server database are migrated to the schema named with that database name.

- All procedures owned by one user are migrated to the schema named with that user's name.

To support these three ways of organizing migrated procedures, you may specify one of these schema name options for translating procedure names. Object names in the translated Oracle procedure call are not case-sensitive.

### Enabling Event Notification for Connection Failures in an Oracle RAC Environment

If the `SQL_ORCLATTR_FAILOVER_CALLBACK` and `SQL_ORCLATTR_FAILOVER_HANDLE` attributes of the `SQLSetConnectAttr` function are set when a connection failure occurs in an Oracle Real Application Clusters (Oracle RAC) Database environment, event notification is enabled. Both attributes are set using the `SQLSetConnectAttr` function. The symbols for the new attributes are defined in the file sqora.h.

The `SQL_ORCLATTR_FAILOVER_CALLBACK` attribute is used to specify the address of a routine to call when a failure event takes place.

The `SQL_ORCLATTR_FAILOVER_HANDLE` attribute is used to specify a context handle which will be passed as one of the parameters in the callback routine. This attribute is necessary in order for the ODBC application to determine which connection the failure event is taking place on.

The function prototype for the callback routine is:

    void failover_callback(void *handle, SQLINTEGER fo_code)

The 'handle' parameter is the value that was set by the `SQL_ORCLATTR_FAILOVER_HANDLE` attribute. Null is returned if the attribute has not been set.

The `fo_code` parameter identifies the failure event which is taking place. The failure events map directly to the events defined in the OCI programming interface. The list of possible events is:

- `ODBC_FO_BEGIN`

- `ODBC_FO_ERROR`

- `ODBC_FO_ABORT`

- `ODBC_FO_REAUTH`

- `ODBC_FO_END`

The following is a sample program which demonstrates using this feature:

    /*
      NAME
      ODBCCallbackTest

      DESCRIPTION
      Simple program to demonstrate the connection failover callback feature.

      PUBLIC FUNCTION(S)
      main

      PRIVATE FUNCTION(S)

      NOTES

      Command Line: ODBCCallbackTest filename [odbc-driver]

    */

    #include <windows.h>
    #include <tchar.h>
    #include <malloc.h>
    #include <stdio.h>
    #include <string.h>
    #include <sql.h>
    #include <sqlext.h>
    #include "sqora.h"

    /*
    ** Function Prototypes
    */
    void display_errors(SQLSMALLINT HandleType, SQLHANDLE Handle);
    void failover_callback(void *Handle, SQLINTEGER fo_code);

    /*
    ** Macros
    */
    #define ODBC_STS_CHECK(sts) \
      if (sts != SQL_SUCCESS) \
    { \
      display_errors(SQL_HANDLE_ENV, hEnv); \
      display_errors(SQL_HANDLE_DBC, hDbc); \
      display_errors(SQL_HANDLE_STMT, hStmt); \
      return FALSE; \
    }

    /*
    ** ODBC Handles
    */
    SQLHENV *hEnv = NULL; // ODBC Environment Handle
    SQLHANDLE *hDbc = NULL; // ODBC Connection Handle
    SQLHANDLE *hStmt = NULL; // ODBC Statement Handle

    /*
    ** Connection Information
    */
    TCHAR *dsn = _T("odbctest");
    TCHAR *uid = _T("scott");
    TCHAR *pwd = _T("tiger");
    TCHAR *szSelect = _T("select * from emp");

    /*
    ** MAIN Routine
    */
    main(int argc, char **argv)
    {
      SQLRETURN rc;

      /*
      ** Allocate handles
      */
      rc = SQLAllocHandle(SQL_HANDLE_ENV, SQL_NULL_HANDLE, (SQLHANDLE *)&hEnv);
      ODBC_STS_CHECK(rc)

      rc = SQLSetEnvAttr(hEnv, SQL_ATTR_ODBC_VERSION, (SQLPOINTER)SQL_OV_ODBC3, 0);
      ODBC_STS_CHECK(rc);

      rc = SQLAllocHandle(SQL_HANDLE_DBC, hEnv, (SQLHANDLE *)&hDbc);
      ODBC_STS_CHECK(rc);

      /*
      ** Connect to the database
      */
      rc = SQLConnect(hDbc, dsn, (SQLSMALLINT)_tcslen(dsn),
      uid, (SQLSMALLINT)_tcslen(uid),
      pwd, (SQLSMALLINT)_tcslen(pwd));
      ODBC_STS_CHECK(rc);

      /*
      ** Set the connection failover attributes
      */
      rc = SQLSetConnectAttr(hDbc, SQL_ORCLATTR_FAILOVER_CALLBACK, &failover_callback, 0);
      ODBC_STS_CHECK(rc);

      rc = SQLSetConnectAttr(hDbc, SQL_ORCLATTR_FAILOVER_HANDLE, hDbc, 0);
      ODBC_STS_CHECK(rc);

      /*
      ** Allocate the statement handle
      */
      rc = SQLAllocHandle(SQL_HANDLE_STMT, hDbc, (SQLHANDLE *)&hStmt);
      ODBC_STS_CHECK(rc);

      /*
      ** Wait for connection failovers
      */
      while (TRUE)
      {
      Sleep(5000);

      rc = SQLExecDirect(hStmt,szSelect, _tcslen(szSelect));
      ODBC_STS_CHECK(rc);

      rc = SQLFreeStmt(hStmt, SQL_CLOSE);
      ODBC_STS_CHECK(rc);
      }

      /*
      ** Free up the handles and close the connection
      */
      rc = SQLFreeHandle(SQL_HANDLE_STMT, hStmt);
      ODBC_STS_CHECK(rc);

      rc = SQLDisconnect(hDbc);
      ODBC_STS_CHECK(rc);

      rc = SQLFreeHandle(SQL_HANDLE_DBC, hDbc);
      ODBC_STS_CHECK(rc);

      rc = SQLFreeHandle(SQL_HANDLE_ENV, hEnv);
      ODBC_STS_CHECK(rc);

      return TRUE;
    }

    /*
    ** Failover Callback Routine
    */
    void failover_callback(void *Handle, SQLINTEGER fo_code)
    {
      switch (fo_code) {

      case ODBC_FO_BEGIN:
      printf("ODBC_FO_BEGIN recevied\n");
      break;

      case ODBC_FO_ERROR:
      printf("ODBC_FO_ERROR recevied\n");
      break;

      case ODBC_FO_ABORT:
      printf("ODBC_FO_ABORT recevied\n");
      break;

      case ODBC_FO_REAUTH:
      printf("ODBC_FO_REAUTH recevied\n");
      break;

      case ODBC_FO_END:
      printf("ODBC_FO_END recevied\n");
      break;

      default:
      printf("Invalid or unknown ODBC failover code recevied\n");
      break;

      };

      return;

    }

    /*
    ** Retrieve the errors associated with the handle passed
    ** and display them.
    */
    void display_errors(SQLSMALLINT HandleType, SQLHANDLE Handle)
    {
      SQLTCHAR MessageText[256];
      SQLTCHAR SqlState[5+1];
      SQLSMALLINT i=1;
      SQLINTEGER NativeError;
      SQLSMALLINT TextLength;
      SQLRETURN sts = SQL_SUCCESS;

      if (Handle == NULL) return;

      /* Make sure all SQLState text is null terminated */
      SqlState[5] = '\0';

      /*
      ** Fetch and display all diagnostic records that exist for this handle
      */
      while (sts == SQL_SUCCESS)
      {
      NativeError = 0;
      TextLength = 0;
      sts = SQLGetDiagRec(HandleType, Handle, i, SqlState, &NativeError,
      (SQLTCHAR *)&MessageText, sizeof(MessageText),
      &TextLength);

      if (sts == SQL_SUCCESS)
      {
      printf("[%s]%s\n", SqlState, MessageText);
      if (NativeError != 0)
      {
      printf("Native Error Code: %d\n", NativeError);
      }
      i++;
      }
      }

      return;
    }

### Using Implicit Results Feature Through ODBC

Use this option when you migrate any third party ODBC application to Oracle Database and you want to use implicit results functionality as supported by the previous vendor. Oracle ODBC driver supports implicit results with stored procedures or an anonymous PL/SQL block. For the current release, implicit results are returned only for `SELECT` statements.

The following code example shows an example ODBC test case using an anonymous SQL script for implicit results.

    const char *query1="declare \
                      c1 sys_refcursor; \
                      c2 sys_refcursor; \
                      begin \
                      open c1 for select empno,ename from emp where rownum<=3; \
                      dbms_sql.return_result(c1); \
                      open c2 for select empno,ename from emp where rownum<=3; \
                      dbms_sql.return_result(c2); end; ";

    int main( )
    {
      ...
       ...
     //Allocate all required handles and establish a connection to the database.

     //Prepare and execute the above anonymous PL/SQL block
        SQLPrepare (hstmt, (SQLCHAR *) query1, SQL_NTS);
        SQLExecute(hstmt);

     //Bind the columns for the results from the first SELECT statement in an anonymous block.
        SQLBindCol (hstmt, 1, SQL_C_ULONG, &eno, 0, &jind);
        SQLBindCol (hstmt, 2, SQL_C_CHAR, empname, sizeof (empname),&enind);

     //Fetch implicit results through the SQLFetch( ) call.
        while((retCode = SQLFetch(hstmt)) != SQL_NO_DATA)
        {
     //Do whatever you want to do with the data.
        }

         retCode = SQLMoreResults(hstmt);

         if(retCode == SQL_SUCCESS)
        {
          printf("SQLMoreResults returned with SQL_SUCCESS\n");

     //Bind the columns for the results from the second SELECT statement in an anonymous block.
        SQLBindCol (hstmt, 1, SQL_C_ULONG, &eno, 0, &jind);
        SQLBindCol (hstmt, 2, SQL_C_CHAR, empname, sizeof (empname),&enind);

     //Fetch implicit results through the SQLFetch( ) call.
        while((retCode = SQLFetch(hstmt)) != SQL_NO_DATA)
        {
     //Do whatever you want to do with data.
        }
      }
    }

### Supported Functionality

- API Conformance

- Implementation of ODBC API Functions

- Implementation of the ODBC SQL Syntax

- Implementation of Data Types (Programming)

#### API Conformance

Oracle ODBC Driver release 9.2.0.0.0 and higher supports all Core, Level 2, and Level 1 functions.

In addition, Oracle ODBC Driver release 9.2.0.0.0 and higher supports translation DLLs.

The following topics describe the ODBC API functions implemented by the Oracle ODBC Driver.

Related Topic for Advanced Users

Error Messages

Related Topic for Programmers

Implementation of ODBC API Functions

#### Implementation of ODBC API Functions

Table 1-7 How Oracle ODBC Driver Implements Specific Functions

Function | Description
--- | ---
`SQLConnect` | SQLConnect requires only a DBQ, user ID, and password.
`SQLDriverConnect` | SQLDriverConnect uses the DSN, DBQ, UID, and PWD keywords.
`SQLMoreResults` | Implements ODBC support for implicit results. This is a new API implemented for release 12.1. See `http://msdn.microsoft.com/en-us/library/ms714673(v=VS.85).aspx` for more information.
`SQLSpecialColumns` | If `SQLSpecialColumns` is called with the `SQL_BEST_ROWID` attribute, it always returns the rowid column.
`SQLProcedures` and`SQLProcedureColumns` | See the information that follows.
All catalog functions | If the `SQL_ATTR_METADATA_ID` statement attribute is set to `SQL_TRUE`, a string argument is treated as an identifier argument, and its case is not significant. In this case, the underscore ("_") and the percent sign ("%") will be treated as the actual character, not as a search pattern character. On the other hand, if this attribute is set to `SQL_FALSE`, it is either an ordinary argument or a pattern value argument and is treated literally, and its case is significant.

#### Implementation of the ODBC SQL Syntax

If a comparison predicate has a parameter marker as the second expression in the comparison and the value of that parameter is set to `SQL_NULL_DATA` with `SQLBindParameter`, the comparison will fail. This is consistent with the null predicate syntax in ODBC SQL.

#### Implementation of Data Types (Programming)

For programmers, the noteworthy part of the implementation of the data types concerns the `CHAR`, `VARCHAR`, and `VARCHAR2` data types.

For an fSqlType value of `SQL_VARCHAR`, `SQLGetTypeInfo` returns the Oracle database data type `VARCHAR2`. For an fSqlType value of `SQL_CHAR`, `SQLGetTypeInfo` returns the Oracle database data type `CHAR`.

### Unicode Support

- Unicode Support Within the ODBC Environment

- Unicode Support in ODBC API

- Unicode Functions in the Driver Manager

- SQLGetData Performance

- Unicode Samples

#### Unicode Support Within the ODBC Environment

The Microsoft or unixODBC ODBC Driver Manager (Driver Manager) makes all ODBC drivers, regardless if they support Unicode, appear as if they are Unicode compliant. This allows ODBC applications to be written independent of the Unicode capabilities of underlying ODBC drivers.

The extent to which the Driver Manager can emulate Unicode support for ANSI ODBC drivers is limited by the conversions possible between the Unicode data and the local code page. Data loss is possible when the Driver Manager is converting from Unicode to the local code page. Full Unicode support is not possible unless the underlying ODBC driver supports Unicode. The Oracle ODBC Driver provides full Unicode support.

#### Unicode Support in ODBC API

The ODBC API supports both Unicode and ANSI entry points using the "W" and "A" suffix convention. An ODBC application developer does not need to explicitly call entry points with the suffix. An ODBC application that is compiled with the UNICODE and _UNICODE preprocessor definitions will generate the appropriate calls. For example, a call to `SQLPrepare` will be compiled as `SQLPrepareW`.

The C data type, `SQL_C_WCHAR`, was added to the ODBC interface to allow applications to specify that an input parameter is encoded as Unicode or to request column data returned as Unicode. The macro `SQL_C_TCHAR` is useful for applications that need to be built as both Unicode and ANSI. The `SQL_C_TCHAR` macro compiles as `SQL_C_WCHAR` for Unicode applications and as `SQL_C_CHAR` for ANSI applications.

The SQL data types, `SQL_WCHAR`, `SQL_WVARCHAR`, and `SQL_WLONGVARCHAR`, have been added to the ODBC interface to represent columns defined in a table as Unicode. Potentially, these values are returned from calls to `SQLDescribeCol`, `SQLColAttribute`, `SQLColumns`, and `SQLProcedureColumns`.

Unicode encoding is supported for SQL column types `NCHAR`, `NVARCHAR2`, and `NCLOB`. In addition, Unicode encoding is also supported for SQL column types `CHAR` and `VARCHAR2` if the character semantics are specified in the column definition.

The ODBC Driver supports these SQL column types and maps them to ODBC SQL data types.

Table 1-8 Supported SQL Data Types and the Equivalent ODBC SQL Data Type

SQL Data Types | ODBC SQL Data Types
--- | ---
`CHAR` | `SQL_CHAR` or `SQL_WCHAR` Foot 1
`VARCHAR2` | `SQL_VARCHAR` or `SQL_WVARCHAR` Foot 2
`NCHAR` | `SQL_WCHAR`
`NVARCHAR2` | `SQL_WVARCHAR`
`NCLOB` | `SQL_WLONGVARCHAR`

Footnote 1 `CHAR` maps to `SQL_WCHAR` if the character semantics were specified in the column definition and if the character set for the database is Unicode.

Footnote 2 `VARCHAR2` maps to `SQL_WVARCHAR` if the character semantics were specified in the column definition and if the character set for the database is Unicode.

#### Unicode Functions in the Driver Manager

The Driver Manager performs the following functions when it detects that the underlying ODBC driver does not support Unicode:

- Convert Unicode function calls to ANSI function calls before calling the ANSI ODBC driver. String arguments will be converted from Unicode to the local code page. For example, a call to `SQLPrepareW` is converted to call `SQLPrepare`. The text of the SQL statement parameter is converted from Unicode to the local code page.

- Convert return parameters that are character data from the local code page to Unicode. For example, returning the column name through `SQLColAttribute`.

- Convert data from the local code page to Unicode for columns bound as `SQL_C_WCHAR`.

- Convert data from Unicode to the local code page for input parameters bound as `SQL_C_WCHAR`.

#### SQLGetData Performance

The `SQLGetData` function allows an ODBC application to specify the data type to receive a column as after the data has been fetched. OCI requires the Oracle ODBC Driver to specify the data type before it is fetched. In this case, the Oracle ODBC Driver uses the knowledge it has about the data type of the column as defined in the database to determine how to best default to fetching the column through OCI.

If a column that contains character data is not bound by `SQLBindCol`, the Oracle ODBC Driver needs to determine if it should fetch the column as Unicode or as the local code page. The driver could always default to receiving the column as Unicode, however, this may result in as many as two unnecessary conversions. For example, if the data were encoded in the database as ANSI, there would be an ANSI to Unicode conversion to fetch the data into the Oracle ODBC Driver. If the ODBC application then requested the data as `SQL_C_CHAR`, there would be an additional conversion to revert the data back to its original encoding.

The default encoding of the Oracle client will be used when fetching data. However, an ODBC application may overwrite this default and fetch the data as Unicode by binding the column or the parameter as the `WCHAR` data type.

#### Unicode Samples

As the Oracle ODBC Driver itself was implemented using TCHAR macros, it is recommended that ODBC application programs use TCHAR in order to take advantage of the driver.

The following links are program examples showing how to use TCHAR, which becomes the `WCHAR` data type in case you compile with UNICODE and _UNICODE.

- Example 1: Connection to Database

- Example 2: Simple Retrieval

- Example 3: Retrieval Using SQLGetData (Binding After Fetch)

- Example 4: Simple Update

- Example 5: Update and Retrieval for Long Data (CLOB)

Example 1: Connection to Database

No difference other than specifying Unicode literals for `SQLConnect`.

    HENV envHnd;
    HDBC conHnd
    ;
    HSTMT stmtHnd;
    RETCODE rc;

    rc = SQL_SUCCESS;

    // ENV is allocated
    rc = SQLAllocEnv(&envHnd);
    // Connection Handle is allocated
    rc = SQLAllocConnect(envHnd, &conHnd);
    rc = SQLConnect(conHnd, _T("stpc19"), SQL_NTS, _T("scott"), SQL_NTS, _T("tiger"),
     SQL_NTS);
    .
    .
    .
    if (conHnd)
    SQLFreeConnect(conHnd);
    if (envHnd)
      SQLFreeEnv(envHnd);

Example 2: Simple Retrieval

The following example retrieves the employee names and the job titles from the `EMP` table. With the exception that you need to specify TCHAR compliant data to every ODBC function, there is no difference to the ANSI case. If the case is a Unicode application, you have to specify the length of the buffer to the `BYTE` length when you call `SQLBindCol` (for example, `sizeof(ename)` ).

    /*
    ** Execute SQL, bind columns, and Fetch.
    ** Procedure:
    **
    ** SQLExecDirect
    ** SQLBindCol
    ** SQLFetch
    **
    */
    static SQLTCHAR *sqlStmt = _T("SELECT ename, job FROM emp");
    SQLTCHAR ename[50];
    SQLTCHAR job[50];
    SQLINTEGER enamelen, joblen;

    _tprintf(_T("Retrieve ENAME and JOB using SQLBindCol 1.../n[%s]/n"), sqlStmt);

    // Step 1: Prepare and Execute
    rc = SQLExecDirect(stmtHnd, sqlStmt, SQL_NTS); // select
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    // Step 2: Bind Columns
    rc = SQLBindCol(stmtHnd,
    1,
    SQL_C_TCHAR,
    ename,
    sizeof(ename),
    &enamelen);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    rc = SQLBindCol(stmtHnd,
    2,
    SQL_C_TCHAR,
    job,
    sizeof(job),
    &joblen);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    do
    {
    // Step 3: Fetch Data
    rc = SQLFetch(stmtHnd);
    if (rc == SQL_NO_DATA)
    break;
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);
    _tprintf(_T("ENAME = %s, JOB = %s/n"), ename, job);
    } while (1);
    _tprintf(_T("Finished Retrieval/n/n"));

Example 3: Retrieval Using SQLGetData (Binding After Fetch)

This example shows how to use `SQLGetData`. For those who are not familiar with ODBC programming, the fetch is allowed before binding the data using `SQLGetData`, unlike in an OCI program. There is no difference to the ANSI application in terms of Unicode-specific issues.

    /*
    ** Execute SQL, bind columns, and Fetch.
    ** Procedure:
    **
    ** SQLExecDirect
    ** SQLFetch
    ** SQLGetData
    */
    static SQLTCHAR *sqlStmt = _T("SELECT ename,job FROM emp"); // same as Case 1.
    SQLTCHAR ename[50];
    SQLTCHAR job[50];

    _tprintf(_T("Retrieve ENAME and JOB using SQLGetData.../n[%s]/n"), sqlStmt);
    if (rc != SQL_SUCCESS)
    {
    _tprintf(_T("Failed to allocate STMT/n"));
    goto exit2;
    }

    // Step 1: Prepare and Execute
    rc = SQLExecDirect(stmtHnd, sqlStmt, SQL_NTS); // select
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    do
    {

    // Step 2: Fetch
    rc = SQLFetch(stmtHnd);
    if (rc == SQL_NO_DAT
    break;

    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    // Step 3: GetData
    rc = SQLGetData(st
    mtHnd,
    1,
    SQL_C_TCHAR,
    (SQLPOINTER)ename,
    sizeof(ename),
    NULL);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);
    rc = SQLGetData(stmtHnd,
    2,
    SQL_C_TCHAR,
    (SQLPOINTER)job,
    sizeof(job),
    NULL);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);
    _tprintf(_T("ENAME = %s, JOB = %s/n"), ename, job);
    } while (1);
    _tprintf(_T("Finished Retrieval/n/n"));

Example 4: Simple Update

This example shows how to update data. Likewise, the length of data for `SQLBindParameter` has to be specified with the `BYTE` length, even in the case of a Unicode application.

    /
    *
    ** Execute SQL, bind columns, and Fetch.
    ** Procedure:
    **
    ** SQLPrepare
    ** SQLBindParameter
    ** SQLExecute
    */
    static SQLTCHAR *sqlStmt = _T("INSERT INTO emp(empno,ename,job) VALUES(?,?,?)");
    static SQLTCHAR *empno = _T("9876"); // Emp No
    static SQLTCHAR *ename = _T("ORACLE"); // Name
    static SQLTCHAR *job = _T("PRESIDENT"); // Job

    _tprintf(_T("Insert User ORACLE using SQLBindParameter.../n[%s]/n"), sqlStmt);

    // Step 1: Prepar
    rc = SQLPrepare(stmtHnd, sqlStmt, SQL_NTS); // select
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    // Step 2: Bind Parameterrc = SQLBindParameter(stmtHnd,
    1,
    SQL_PARAM_INPUT,
    SQL_C_TCHAR,
    SQL_DECIMAL,
    4, // 4 digit
    0,
    (SQLPOINTER)empno,
    0,
    NULL);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    rc = SQLBindParameter(stmtHnd,
    2,
    SQL_PARAM_INPUT,
    SQL_C_TCHAR,
    SQL_CHAR,
    lstrlen(ename)*sizeof(TCHAR),
    0,
    (SQLPOINTER)ename,
    lstrlen(ename)*sizeof(TCHAR),
    NULL);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    rc = SQLBindParameter(stmtHnd,
    3,
    SQL_PARAM_INPUT,
    SQL_C_TCHAR,
    SQL_CHAR,
    lstrlen(job)*sizeof(TCHAR),
    0,
    (SQLPOINTER)job,
    lstrlen(job)*sizeof(TCHAR),
    NULL);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    // Step 3: Execute
    rc = SQLExecute(stmtHnd);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

Example 5: Update and Retrieval for Long Data (CLOB)

This example may be the most complicated case to update and retrieve data for long data, like `CLOB`, in Oracle. Since the length of data should be always the `BYTE` length, `lstrlen(TCHAR data)*sizeof(TCHAR)` is needed to derive the `BYTE` length.

    /*
    ** Execute SQL, bind columns, and Fetch.
    ** Procedure:
    **
    ** SQLPrepare
    ** SQLBindParameter
    ** SQLExecute
    ** SQLParamData
    ** SQLPutData
    **
    ** SQLExecDirect
    ** SQLFetch
    ** SQLGetData
    */
    static SQLTCHAR *sqlStmt1 = _T("INSERT INTO clobtbl(clob1) VALUES(?)");
    static SQLTCHAR *sqlStmt2 = _T("SELECT clob1 FROM clobtbl");
    SQLTCHAR clobdata[1001];
    SQLTCHAR resultdata[1001];
    SQLINTEGER ind = SQL_DATA_AT_EXEC;
    SQLTCHAR *bufp;
    int clobdatalen, chunksize, dtsize, retchklen;

    _tprintf(_T("Insert CLOB1 using SQLPutData.../n[%s]/n"), sqlStmt1);

    // Set CLOB Data
    {
    int i;
    SQLTCHAR ch;
    for (i=0, ch=_T('A'); i< sizeof(clobdata)/sizeof(SQLTCHAR); ++i, ++ch)
    {
    if (ch > _T('Z'))
    ch = _T('A');
    clobdata[i] = ch;
    }
    clobdata[sizeof(clobdata)/sizeof(SQLTCHAR)-1] = _T('/0');
    }
    clobdatalen = lstrlen(clobdata); // length of characters
    chunksize = clobdatalen / 7; // 7 times to put

    // Step 1: Prepare
    rc = SQLPrepare(stmtHnd, sqlStmt1, SQL_NTS);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    // Step 2: Bind Parameter with SQL_DATA_AT_EXEC
    rc = SQLBindParameter(stmtHnd,
    1,
    SQL_PARAM_INPUT,
    SQL_C_TCHAR,
    SQL_LONGVARCHAR,
    clobdatalen*sizeof(TCHAR),
    0,
    (SQLPOINTER)clobdata,
    clobdatalen*sizeof(TCHAR),
    &ind);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    // Step 3: Execute
    rc = SQLExecute(stmtHnd);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    // Step 4: ParamData (initiation)
    rc = SQLParamData(stmtHnd, (SQLPOINTER*)&bufp); // set value
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    for (dtsize=0, bufp = clobdata;
    dtsize < clobdatalen;
    dtsize += chunksize, bufp += chunksize)
    {
    int len;
    if (dtsize+chunksize<clobdatalen)
    len = chunksize;
    else
    len = clobdatalen-dtsize;

    // Step 5: PutData
    rc = SQLPutData(stmtHnd, (SQLPOINTER)bufp, len*sizeof(TCHAR));
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);
    }

    // Step 6: ParamData (temination)
    rc = SQLParamData(stmtHnd, (SQLPOINTER*)&bufp);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    rc = SQLFreeStmt(stmtHnd, SQL_CLOSE);
    _tprintf(_T("Finished Update/n/n"));
    rc = SQLAllocStmt(conHnd, &stmtHnd);
    if (rc != SQL_SUCCESS)
    {
    _tprintf(_T("Failed to allocate STMT/n"));
    goto exit2;
    }

    // Clear Result Data
    memset(resultdata, 0, sizeof(resultdata));
    chunksize = clobdatalen / 15; // 15 times to put

    // Step 1: Prepare
    rc = SQLExecDirect(stmtHnd, sqlStmt2, SQL_NTS); // select
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    // Step 2: Fetch
    rc = SQLFetch(stmtHnd);
    checkSQLErr(envHnd, conHnd, stmtHnd, rc);

    for(dtsize=0, bufp = resultdata;
    dtsize < sizeof(resultdata)/sizeof(TCHAR) && rc != SQL_NO_DATA;
    dtsize += chunksize-1, bufp += chunksize-1)
    {
    int len; // len should contain the space for NULL termination
    if (dtsize+chunksize<sizeof(resultdata)/sizeof(TCHAR))
    len = chunksize;
    else
    len = sizeof(resultdata)/sizeof(TCHAR)-dtsize;

    // Step 3: GetData
    rc = SQLGetData(stmtHnd,
    1,
    SQL_C_TCHAR,
    (SQLPOINTER)bufp,
    len*sizeof(TCHAR),
    &retchklen);
    }
    if (!_tcscmp(resultdata, clobdata))
    {
    _tprintf(_T("Succeeded!!/n/n"));
    }
    else
    {
    _tprintf(_T("Failed!!/n/n"));
    }

### Performance and Tuning

- General ODBC Programming Tips

- Data Source Configuration Options

- DATE and TIMESTAMP Data Types

#### General ODBC Programming Tips

This section describes some general programming tips to improve the performance of an ODBC application.

- Enable connection pooling if the application will frequently connect and disconnect from a data source. Reusing pooled connections is extremely efficient compared to reestablishing a connection.

- Minimize the number of times a statement needs to be prepared. Where possible, use bind parameters to make a statement reusable for different parameter values. Preparing a statement once and executing it several times is much more efficient than preparing the statement for every `SQLExecute`.

- Do not include columns in a `SELECT` statement of which you know the application will not retrieve; especially `LONG` columns. Due to the nature of the database server protocols, the ODBC Driver must fetch the entire contents of a `LONG` column if it is included in the `SELECT` statement, regardless if the application binds the column or does a `SQLGetData`.

- If you are performing transactions that do not update the data source, set the `SQL_ATTR_ACCESS_MODE` attribute of the ODBC `SQLSetConnectAttr` function to `SQL_MODE_READ_ONLY`.

- If you are not using ODBC escape clauses, set the `SQL_ATTR_NOSCAN` attribute of the ODBC `SQLSetConnectAttr` function or the ODBC `SQLSetStmtAttr` function to true.

- Use the ODBC `SQLFetchScroll` function instead of the ODBC `SQLFetch` function for retrieving data from tables that have a large number of rows.

- Enable OCI statement caching when the same SQL statements are used multiple times (`StatementCache=T`).

- Binding `NUMBER` columns as `FLOAT` speeds up query execution (`BindAsFLOAT=T`).

- While fetching `LONG` or `LONG RAW` set `MaxLargeData=<value>` for optimum performance.

- Setting `UseOCIDescribeAny=T` for applications making heavy calls to small packaged procedures that return `Ref Cursor` will see performance improvement.

#### Data Source Configuration Options

This topic discusses performance implications of the following ODBC data source configuration options:

- Enable Result Sets

- Enable LOBs

- Bind TIMESTAMP as DATE

- Enable Closing Cursors

- Enable Thread Safety

- Fetch Buffer Size

Enable Result Sets

This option enables the support of returning result sets (for example, `RefCursor`) from procedure calls. The default is enabling the returning of result sets.

The ODBC Driver must query the database server to determine the set of parameters for a procedure and their data types in order to determine if there are any `RefCursor` parameters. This query incurs an additional network round trip the first time any procedure is prepared and executed.

Enable LOBs

This option enables the support of inserting and updating LOBs. The default is enabled.

The ODBC Driver must query the database server to determine the data types of each parameter in an `INSERT` or `UPDATE` statement in order to determine if there are any LOB parameters. This query incurs an additional network round trip the first time any `INSERT` or `UPDATE` is prepared and executed.

Bind TIMESTAMP as DATE

Binds `SQL_TIMESTAMP` parameters as the appropriate Oracle data type. If this option is set to `TRUE`, `SQL_TIMESTAMP` binds as the Oracle `DATE` data type. If this option is set to `FALSE`, `SQL_TIMESTAMP` binds as the Oracle `TIMESTAMP` data type (which is the default).

Enable Closing Cursors

The `SQL_CLOSE` option of the ODBC function, `SQLFreeStmt`, is supposed to close associated cursors with a statement and discard all pending results. The application can reopen the cursor by executing the statement again without doing a `SQLPrepare` again. A typical scenario for this would be an application which expects to be idle for a while but will reuse the same SQL statement again. While the application is idle, it may want to free up any associated server resources.

The Oracle Call Interface (OCI), on which the Oracle ODBC Driver is layered, does not support the functionality of closing cursors. So, by default, the `SQL_CLOSE` option has no effect in the Oracle ODBC Driver. The cursor and associated resources remain open on the database server.

Enabling this option will cause the associated cursor to be closed on the database server. However, this results in the parse context of the SQL statement being lost. The ODBC application can execute the statement again without calling `SQLPrepare`. However, internally the ODBC Driver must prepare and execute the statement all over. Enabling this option will have a severe performance impact on applications that prepare a statement once and execute it repeatedly.

This option should only be enabled if freeing the resources on the server is absolutely necessary.

Enable Thread Safety

If an application is single threaded, this option can be disabled. By default, the ODBC Driver ensures that access to all internal structures (environment, connection, statement) are thread safe. Single threaded applications can eliminate some of the thread safety overhead by disabling this option. Disabling this option should show a minor performance improvement.

Fetch Buffer Size

Set the Fetch Buffer Size in the Oracle Options tab of the Oracle ODBC Driver Configuration Dialog Box to a value specified in bytes. This value is the amount of memory needed that will determine how many rows of data the ODBC Driver will pre-fetch at a time from an Oracle database to the client's cache regardless of the number of rows the application program requests in a single query, thus improving performance.

Applications that typically fetch fewer than 20 rows of data at a time will see an improvement in response time, particularly over slow network connections or to heavily loaded servers. Setting this too high can actually make response time worse or consume large amounts of memory. The default is 64,000 bytes. Choose a value that works best for your application.

Note: When `LONG` and LOB data types are present, the number of rows pre-fetched by the ODBC Driver is not determined by the Fetch Buffer Size. The inclusion of the `LONG` and LOB data types minimizes the performance improvement and could result in excessive memory use. The ODBC Driver will disregard the Fetch Buffer Size and only pre-fetch a set number of rows in the presence of the `LONG` and LOB data types.

#### DATE and TIMESTAMP Data Types

If a `DATE` column in the database is used in a `WHERE` clause and the column has an index, there can be an impact on performance. For example:

    SELECT * FROM EMP WHERE HIREDATE = ?

In this example, an index on the `HIREDATE` column could be used to make the query execute quickly. But, because `HIREDATE` is actually a `DATE` value and the ODBC Driver is supplying the parameter value as `TIMESTAMP`, the Oracle server's query optimizer must apply a conversion function. To prevent incorrect results (as might happen if the parameter value had nonzero fractional seconds), the optimizer applies the conversion to the `HIREDATE` column resulting in the following statement:

    SELECT * FROM EMP WHERE TO_TIMESTAMP(HIREDATE) = ?

Unfortunately, this has the effect of disabling the use of the index on the `HIREDATE` column and instead the server performs a sequential scan of the table. If the table has many rows, this can take a long time. As a workaround for this situation, the ODBC Driver has the connection option to `Bind TIMESTAMP as DATE`. When this option is enabled, the ODBC Driver binds `SQL_TIMESTAMP` parameters as the Oracle `DATE` data type instead of the Oracle `TIMESTAMP` data type. This allows the query optimizer to use any index on the `DATE` columns.

Note: This option is intended only for use with Microsoft Access or other similar programs that bind `DATE` columns as `TIMESTAMP` columns. It should not be used when there are actual `TIMESTAMP` columns present or when data loss may occur. Microsoft Access executes such queries using whatever columns are selected as the primary key.

Related Topic

Implementation of Data Types (Advanced)

## Glossary

API

Application Program Interface. A set of program functions or calls that allow an application to make use of, or communicate with, an underlying program or system.

Client

A client is a software program that accesses data by selecting a service provided by a server using an agreed upon interface. The server responds by receiving and processing client requests, and sending the results back to the client. ODBC client applications use the ODBC Driver API to call ODBC functions to submit SQL statements and retrieve results.

Conformance Levels

Some applications can only use drivers that support certain levels of functionality or conformance levels. For example, an application might want to set the cursor position in a rowset and allow an application to refresh data in the rowset. This ability is part of the Level 1 conformance level for the Application Programming Interface (API).

ODBC drivers conform to Core API level and part of Level 1 and Level 2 and is broadly compatible with the SQL-99 Core specification. Drivers may support some of the functionality in levels above their stated level.

For detailed information about what is in the various conformance levels, programmers should see the Microsoft ODBC 3.52 Software Development Kit and Programmer's Reference.

Data Source

A data source includes information about the data a user wants to access and information on how to access that data. For the Oracle ODBC Driver, a data source is an alias for a specific instance of an Oracle database and the Oracle Net Services components used for communication to the Oracle database.

DLL

Dynamic Link Library. A set of routines that one or more applications can use to perform common tasks. The ODBC drivers are DLLs on the Windows platform and Shared Object (.so) files on the UNIX platform.

Driver Manager

The Driver Manager, which is provided by Microsoft and unixODBC, loads drivers on behalf of an application when the application calls the ODBC `SQLConnect` or ODBC `SQLDriverConnect` functions.

Network Transports

A network is made up of communications software and hardware through which an OCI client on a machine communicates with an Oracle server on another computer system. Message requests from the OCI client and response requests from the server travel over a Oracle Net Services communications link that can support a variety of network transports.

ODBC

Open Database Connectivity. A Driver Manager and a set of ODBC drivers that enable applications to access data using SQL as a standard language.

ODBC Application

The ODBC application performs processing and calls ODBC functions to submit SQL statements and retrieve results. The application can access multiple data drivers, each of which accesses a different data source.

ODBC Driver

Microsoft's Open Database Connectivity (ODBC) provides a standard interface that allows one application to access many different data sources. The application's source code does not have to be recompiled for each data source. An ODBC driver is a dynamic-link library (DLL) on the Windows platform or a Shared Object (SO) on the UNIX platform that applications can invoke on demand to gain access to a data source. An ODBC driver links the application to a specific data source and processes ODBC function calls, submits SQL requests to a specific data source, and returns results to the application. If necessary, the ODBC driver modifies an application's request so that the request conforms to syntax supported by the associated data source. The Driver Manager and the ODBC driver appear to an application as one unit that processes ODBC function calls. The Oracle ODBC Driver allows read and write access to Oracle databases only.

ODBC drivers are now available for UNIX platforms which works with 3rd party open source Driver Managers (DM). Oracle ODBC Driver has been certified using DM provided by `unixODBC.org` on Unix platforms. (For platform details, refer to the `ODBC_Readme_Unix.html` file.

Oracle

Oracle is a high performance, high availability, scalable, general purpose, multiuser, database management system based on the relational model extended with objects that runs on a wide variety of computer operating systems. Oracle Database 12g is available in a choice of editions tailored to meet the business and IT needs of needs of all sizes of organizations. It supports a full set of utilities and an industry-standard SQL data definition and data manipulation language that lets you create, query, and maintain your Oracle databases. Oracle supports VLDB, high-end OLTP and data warehouse applications, and contains enhanced management capabilities using the Oracle Enterprise Manager GUI and enhanced security using Oracle Advanced Security.

Additionally, Oracle offers a range of Enterprise Edition Options to meet your most demanding requirements for mission-critical transaction processing, data warehousing, and content management applications. These options include: Oracle Active Data Guard, Oracle Advanced Compression, Oracle Advanced Security, Oracle Database Vault, Oracle Data Mining, Oracle In-Memory Database Cache, Oracle Label Security, Oracle OLAP, Oracle Partitioning, Oracle Real Application Clusters, Real Application Testing, Oracle Spatial, Oracle Total Recall, Oracle Warehouse Builder Enterprise ETL Option, Oracle Warehouse Builder Data Quality Option, Oracle Warehouse Builder Connections, and Oracle Content Database Suite.

In addition, Oracle provides an integrated management solution for managing Oracle database with a unique top-down application management approach. With new self-managing capabilities, Oracle eliminates time-consuming, error-prone administrative tasks, so database administrators can focus on strategic business objectives instead of performance and availability fire drills. Oracle provides the following database management packs: Oracle Change Management Pack, Oracle Configuration Management Pack, Oracle Data Masking, Oracle Diagnostic Pack, Pack, Oracle Provisioning and Patch Automation Pack, and Oracle Tuning Pack.

Oracle also offers a variety of related products that include: Oracle Audit Vault, Oracle Secure Backup, Oracle Programmer, Oracle TimesTen In-Memory Database, Oracle Berkeley DB, and Oracle Database Lite.

Oracle Call Interface

The Oracle Call Interface (OCI) is a set of standard software routines (program call interface) used to access an Oracle server. OCI allows users to embed Oracle calls directly into high-level languages.

Oracle Net Services

Oracle Corporation's family of networking products that transparently integrates clients, servers, and gateways to deliver a unified information resource using industry-standard or proprietary network protocols.

Oracle Net Configuration Assistant (NETCA)

A utility to easily configure and maintain an Oracle Net Services network by updating entries in the `tnsnames.ora` file for each of your TNS Service Names.

SQL

Structured Query Language. The internationally accepted standard for relational systems, covering not only query but also data definition, manipulation, security, and some aspects of referential integrity.

TCP/IP

Transmission Control Protocol (TCP)/Internet Protocol (IP). An interprocess communication mechanism used by applications to share data across a network. TCP allows a process on one machine to send a stream of data to a process on another machine. Software implementing TCP usually resides in the operating system and uses the IP to transmit information across the Internet.

## Acknowledgements

This section contains the following acknowledgements:

- Copyright and Trademark Acknowledgements

- Accessibility Statements

### Copyright and Trademark Acknowledgements

Oracle ODBC Driver, Release 12.1.0.1.0

Copyright © 1993, 2013 Oracle. All rights reserved.

This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited.

The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing.

If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable:

U.S. GOVERNMENT END USERS: Oracle programs, including any operating system, integrated software, any programs installed on the hardware, and/or documentation, delivered to U.S. Government end users are "commercial computer software" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, use, duplication, disclosure, modification, and adaptation of the programs, including any operating system, integrated software, any programs installed on the hardware, and/or documentation, shall be subject to license terms and license restrictions applicable to the programs. No other rights are granted to the U.S. Government.

This software or hardware is developed for general use in a variety of information management applications. It is not developed or intended for use in any inherently dangerous applications, including applications that may create a risk of personal injury. If you use this software or hardware in dangerous applications, then you shall be responsible to take all appropriate fail-safe, backup, redundancy, and other measures to ensure its safe use. Oracle Corporation and its affiliates disclaim any liability for any damages caused by use of this software or hardware in dangerous applications.

Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners.

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This software or hardware and documentation may provide access to or information on content, products, and services from third parties. Oracle Corporation and its affiliates are not responsible for and expressly disclaim all warranties of any kind with respect to third-party content, products, and services. Oracle Corporation and its affiliates will not be responsible for any loss, costs, or damages incurred due to your access to or use of third-party content, products, or services.

### Accessibility Statements

For information about Oracle's commitment to accessibility, visit the Oracle Accessibility Program website at `http://www.oracle.com/pls/topic/lookup?ctx=acc&id=docacc`.

Access to Oracle Support

Oracle customers have access to electronic support through My Oracle Support. For information, visit `http://www.oracle.com/pls/topic/lookup?ctx=acc&id=info` or visit `http://www.oracle.com/pls/topic/lookup?ctx=acc&id=trs` if you are hearing impaired.