A subselect is a select which works in conjunction with another select. A nested select is a kind of subselect where the inner select passes to the where criteria for the outer select.

The database descriptor, DBD is the DB2 component that limits access to the database whenever objects are created, altered or dropped.

The two parameters used in the CREATE statement are the PCTFREE which specifies the percentage of free space for each page and FREEPAGE which indicates the number of pages to be loaded with data between each free page. Free space allows room for the insertion of new rows.