When dealing with a database, it is important to understand the “DB2 catalog” concept. The catalog is a set of DB2 tables that store the DB2 system state. Almost every action that takes place in DB2 is reflected in a change to one or more catalog tables.
When dealing with DB2 it is first important to understand which member of the DB2 “family” you are working with. While the DB2 brand is used on a variety of platforms the underlying infrastructure is somewhat different on each.