CICS applications can perform SQL operations using the EXEC SQL statement. By default CICS manages the connection to the database used by EXEC SQL statements within an application program. The connection string used by CICS to connect to a database is defined as part of an XA resource definition (seeAbout XA Resources ). This prevents having to hard-code connection strings within your CICS applications.
The first time a CICS application executes an EXEC SQL statement, the connection string defined by the XA resource definition is used to establishes the database connection. The connection is used for all subsequent SQL operations that the application makes.