MDAC 2.5 SDK - ODBC Programmer's Reference
Chapter 21: ODBC API Reference

SQLEndTran

Conformance

Version Introduced: ODBC 3.0
Standards Compliance: ISO 92

Summary

SQLEndTran requests a commit or rollback operation for all active operations on all statements associated with a connection. SQLEndTran can also request that a commit or rollback operation be performed for all connections associated with an environment.

Note   For more information about what the Driver Manager maps this function to when an ODBC 3.x application is working with an ODBC 2.x driver, see "Mapping Replacement Functions for Backward Compatibility of Applications" in Chapter 17, "Programming Considerations."

Syntax

SQLRETURN SQLEndTran(
     SQLSMALLINT     HandleType,
     SQLHANDLE     Handle,
     SQLSMALLINT     CompletionType);

Arguments

HandleType

[Input]
Handle type identifier. Contains either SQL_HANDLE_ENV (if Handle is an environment handle) or SQL_HANDLE_DBC (if Handle is a connection handle).

Handle

[Input]
The handle, of the type indicated by HandleType, indicating the scope of the transaction. See "Comments" for more information.

CompletionType

[Input]
One of the following two values:

SQL_COMMIT
SQL_ROLLBACK

Returns

SQL_SUCCESS, SQL_SUCCESS_WITH_INFO, SQL_ERROR, or SQL_INVALID_HANDLE.

Diagnostics

When SQLEndTran returns SQL_ERROR or SQL_SUCCESS_WITH_INFO, an associated SQLSTATE value may be obtained by calling SQLGetDiagRec with the appropriate HandleType and Handle. The following table lists the SQLSTATE values commonly returned by SQLEndTran and explains each one in the context of this function; the notation "(DM)" precedes the descriptions of SQLSTATEs returned by the Driver Manager. The return code associated with each SQLSTATE value is SQL_ERROR, unless noted otherwise.

Comments

For an ODBC 3.x driver, if HandleType is SQL_HANDLE_ENV and Handle is a valid environment handle, then the Driver Manager will call SQLEndTran in each driver associated with the environment. The Handle argument for the call to a driver will be the driver's environment handle. For an ODBC 2.x driver, if HandleType is SQL_HANDLE_ENV and Handle is a valid environment handle, and there are multiple connections in a connected state in that environment, then the Driver Manager will call SQLTransact in the driver once for each connection in a connected state in that environment. The Handle argument in each call will be the connection's handle. In either case, the driver will attempt to commit or roll back transactions, depending on the value of CompletionType, on all connections that are in a connected state on that environment. Connections that are not active do not affect the transaction.

Note   SQLEndTran cannot be used to commit or roll back transactions on a shared environment. SQLSTATE HY092 (Invalid attribute/option identifier) will be returned if SQLEndTran is called with Handle set to either the handle of a shared environment or the handle of a connection on a shared environment.

The Driver Manager will return SQL_SUCCESS only if it receives SQL_SUCCESS for each connection. If the Driver Manager receives SQL_ERROR on one or more connections, it returns SQL_ERROR to the application, and the diagnostic information is placed in the diagnostic data structure of the environment. To determine which connection or connections failed during the commit or rollback operation, the application can call SQLGetDiagRec for each connection.

Note   The Driver Manager does not simulate a global transaction across all connections and therefore does not use two-phase commit protocols.

If CompletionType is SQL_COMMIT, SQLEndTran issues a commit request for all active operations on any statement associated with an affected connection. If CompletionType is SQL_ROLLBACK, SQLEndTran issues a rollback request for all active operations on any statement associated with an affected connection. If no transactions are active, SQLEndTran returns SQL_SUCCESS with no effect on any data sources. For more information, see "Committing and Rolling Back Transactions" in Chapter 14, "Transactions."

If the driver is in manual-commit mode (by calling SQLSetConnectAttr with the SQL_ATTR_AUTOCOMMIT attribute set to SQL_AUTOCOMMIT_OFF), a new transaction is implicitly started when an SQL statement that can be contained within a transaction is executed against the current data source. For more information, see "Commit Mode" in Chapter 14, "Transactions."

To determine how transaction operations affect cursors, an application calls SQLGetInfo with the SQL_CURSOR_ROLLBACK_BEHAVIOR and SQL_CURSOR_COMMIT_BEHAVIOR options. For more information, see the following paragraphs and also see "Effect of Transactions on Cursors and Prepared Statements" in Chapter 14, "Transactions."

If the SQL_CURSOR_ROLLBACK_BEHAVIOR or SQL_CURSOR_COMMIT_BEHAVIOR value equals SQL_CB_DELETE, SQLEndTran closes and deletes all open cursors on all statements associated with the connection and discards all pending results. SQLEndTran leaves any statement present in an allocated (unprepared) state; the application can reuse them for subsequent SQL requests or can call SQLFreeStmt or SQLFreeHandle with a HandleType of SQL_HANDLE_STMT to deallocate them.

If the SQL_CURSOR_ROLLBACK_BEHAVIOR or SQL_CURSOR_COMMIT_BEHAVIOR value equals SQL_CB_CLOSE, SQLEndTran closes all open cursors on all statements associated with the connection. SQLEndTran leaves any statement present in a prepared state; the application can call SQLExecute for a statement associated with the connection without first calling SQLPrepare.

If the SQL_CURSOR_ROLLBACK_BEHAVIOR or SQL_CURSOR_COMMIT_BEHAVIOR value equals SQL_CB_PRESERVE, SQLEndTran does not affect open cursors associated with the connection. Cursors remain at the row they pointed to prior to the call to SQLEndTran.

For drivers and data sources that support transactions, calling SQLEndTran with either SQL_COMMIT or SQL_ROLLBACK when no transaction is active returns SQL_SUCCESS (indicating that there is no work to be committed or rolled back) and has no effect on the data source.

When a driver is in autocommit mode, the Driver Manager does not call SQLEndTran in the driver. SQLEndTran always returns SQL_SUCCESS regardless of whether it is called with a CompletionType of SQL_COMMIT or SQL_ROLLBACK.

Drivers or data sources that do not support transactions (SQLGetInfo option SQL_TXN_CAPABLE is SQL_TC_NONE) are effectively always in autocommit mode and therefore always return SQL_SUCCESS for SQLEndTran whether or not they are called with a CompletionType of SQL_COMMIT or SQL_ROLLBACK. Such drivers and data sources do not actually roll back transactions when requested to do so.

Related Functions