If you configure your Enterprise Server instance to run container-managed services (web services or EJBs), CICS or IMS Transactions, or JES jobs accessing databases or MQSeries resources, you also need to configure your server so that it can interact with the resource managers that the application wants to access. In that context you can only use resource managers that are XA-compliant. The XA interface describes a structure called a switch table, which lists the names of the xa_ routines implemented in the resource manager. This structure is called xa_switch_t. To access an XA-compliant resource manager, you need a switch module, the purpose of which is to obtain the address of the XA switch data structure implemented by the resource manager.
If you want to access Oracle, IBM DB2, or SQL Server databases from JES JCLs using IKJEFT01, you must build an additional switch module to use along with the standard switch module.
You specify the details of XA resource managers using the Edit Server > Properties > XA Resources page in the Web interface. You can also edit and delete XA resource manager definitions. You can enable resource managers individually to control which are active when an Enterprise Server instance starts.