You can specify a default collection name to be used by an SQL program by supplying this name for the DFTRDBCOL parameter on the CRTSQLxxx command when you precompile the program.
The DFTRDBCOL parameter provides the program with the collection name as the library for an unqualified file if the *SYS naming convention is used, or as the collection for an unqualified table if the *SQL naming convention is used. If you do not specify a default collection name when you precompile the program, the rules for unqualified names apply for each naming convention. The default relational database collection name only applies to static SQL statements.
You can also use the DFTRDBCOL parameter on the Create Structured Query Language Package (CRTSQLPKG) command to change the default collection of a package. After an SQL program is compiled, you can create a new SQL package to change the default collection.