If you are connecting to a relational database at run time, you need to define a data source for use with your program. The directions are in the help system of the WebSphere® Sever administrative console.
If the data source definition refers to the default database, the value you specify in the User ID field is overridden by any value set in the vgj.jdbc.default.userid property of the J2EE deployment descriptor used at run time, but only if you have specified values for both vgj.jdbc.default.userid and vgj.jdbc.default.password. Similarly, if the data source definition refers to a database that is accessed by way of the system function sysLib.connect or VGLib.connectionService, the value you specify in the User ID field is overridden by any user ID that you specify in the call to that system function, but only if the call passes both a user ID and password.
You specify the name when setting up the authentication alias. To reach the display where you can define that alias, follow this sequence in the Administrative Console: Security > GlobalSecurity > Authentication > JAAS Configuration > J2C Authentication Data.
You specify the password when setting up the authentication alias. To reach the display where you can define that alias, follow this sequence in the Administrative Console: Security > GlobalSecurity > Authentication > JAAS Configuration > J2C Authentication Data.
You may define multiple data sources, in which case you use the system function VGLib.connectionService to switch between them.
For details on the meaning of the deployment descriptor properties, including details on how the generated values are derived, see Java™ runtime properties (reference).