Keys Derived from the DMSII Database

First, DBEngine decides whether any SETs meet this requirement. If more than one SET does, DBEngine uses the SET with the least number of keys. In case of a tie, the SET with the smallest-sized keys is used.

In addition, the DBGenFormat utility allows you to declare a primary key without modifying the DASDL. DBEngine is responsible for passing information about DBGenFormat primary keys to the DATABridge Client. The DATABridge Client sometimes uses these keys for VIRTUAL data sets or any other types of data sets that do not have a SET that meets the requirements mentioned above. If you have both a qualified SET and a PRIMARY KEY defined in the GenFormat file, the PRIMARY KEY is used.

Note: If a DMSII SET with the NO DUPLICATES ALLOWED attribute exists, it is recommended that you use that key rather than declaring a DBGenFormat primary key.

When DBEngine uses a DMSII SET as the index for tables derived from the data set, the name of the DMSII SET is stored in the set_name column of the DATASETS client control table. Alternatively, when DBEngine uses a DBGenFormat primary key as the index for tables derived from the data set, the name "pk_set" is stored in the set_name column.