After initiating a transaction, an application enlists the resource managers it wants to participate in the transaction. Enlistment is done through the ODBC 3.0 connection attribute function call:

SQLSetConnectAttr(SQL_ATTR_ENLIST_IN_DTC)

When integrating a new resource manager into Tuxedo, the file %TUXDIR%/udataobj/RM must be updated to include information about the resource manager. To integrate the OpenLink Lite Driver for Oracle into Tuxedo on Windows, define anrm_alias entry in the RM file by adding a line similar to:

OPL_ORA_XA;(*opl_xa_switch());"c:\program files\openlink\lite32\ntl5o9zz.lib

where, in this example, OPL_ORA_XA is therm_alias.. ntl5o9zz.lib is an import library for the ODBC driver associated with the DSN identified by the xa_info string; in this example the OpenLink Windows Lite Driver for Oracle (ntl5o9zz.dll).

To create anrm_aliasentry in the RM file for the OpenLink Generic Client add a line similar to:

OPL_XA;(*opl_xa_switch());"c:\program files\openlink\olod5032u.lib

On Unix therm_aliasis created in a similar way. A line adding an alias for the OpenLink Generic Client is added to $TUXDIR/udataobj/RM as follows:

OPL_XA:(*opl_xa_switch()):/home/openlink/lib/oplodbcu.so

Where /home/openlink is the openlink installation directory.

The XA functions xa_open and xa_close open or close a connection to a resource manager for the calling thread. Both functions accept anxa_infoargument.xa_infois a string containing instance-specific information for the resource manager. For OpenLink ODBC drivers, the xa_infostring takes the form of an ODBC Data Source Name. The DSN must be defined in your ODBC.INI file or registry hive using the ODBC Administrator.

In a Tuxedo environment, the xa_info strings required by xa_open and xa_close for a particular RM instance are identified by the OPENINFO and CLOSEINFO entries in the UBBCONFIG configuration file. (An example UBBCONFIG file is given below.) OPENINFO and CLOSEINFO entries must be defined for each server group. These entries must be quoted strings of the form "rm_alias:DSN". (OPENINFO and CLOSEINFO should not contain the usualxa_infostring required by the target database. This string is stored as part of the DSN definition when the ODBC data source is configured. The OpenLink ODBC driver retrieves the storedxa_infostring using the DSN it receives through xa_open or xa_close.)

In order for a service to use ODBC functions in the context of a global transaction, the ODBC functions must use the XA connection created when the service connects to the resource manager with which it is linked. (In the sample application, each service connects to a database using tpopen(), when the service is first initialized through tpsvrinit()). OpenLink XA-enabled ODBC drivers provide two functions, SQLGetXaEnv() and SQLGetXaConnect(), which make an XA connection available for use with ODBC. If the XA connection is enlisted in a global transaction, e.g. the client has called tpbegin() before calling the service, then any 'work' done by ODBC functions in the service will be controlled by that global transaction.

SQLGetXaEnv() returns the ODBC environment handle associated with the XA connection. SQLGetXaConnect() returns the ODBC connection handle associated with the XA connection. The prototypes for these functions are:

SQLRETURN SQLGetXaEnv(SQLHENV *phenv); 
    SQLRETURN SQLGetXaConnect(SQLHDBC *phdbc);

When using OpenLink ODBC drivers in a global transaction context, you should not create an environment handle using SQLAllocHandle(), or use SQLSetEnvAttr(). (The SQLHENV associated with the XA connection is created with SQL_ATTR_ODBC_VERSION set to SQL_OV_ODBC3.) If you create an ODBC connection using this SQLHENV, it will not be enlisted in the global transaction.

JTA support is built into the JRE for JDK 1.4 and 1.5, thus the UDA Generic JDBC client (opljdbc3.jar) simply needs to be added to the CLASSPATH and the XA classes will be available for use.

JTA support was added by Sun Microsystems as an extension to the JDK 1.2 and 1.3 JRE's resulting in the following jar files having to be added to you CLASSPATH in additon to the UDA Generic JDBC client (opljdbc2.jar) :

jdbc2_0-stdext.jar
jta-spec1_0_1.jar
jndi.jar

Reference documentation for the OpenLink JDBC XA implementation in the UDA JDBC Client.