Specifying an identity column
Many DBMSs allow you to specify that the value for a column
in a new row is to be automatically assigned by the DBMS. This kind
of column is called an identity column. Different DBMSs provide
different types of identity columns.
For example, some DBMSs allow you to define autoincrement
columns so that the column for a new row is automatically assigned
a value one greater than that of the previous highest value. You
could use this feature to specify that an order number be automatically
incremented when someone adds a new order:
By specifying an identity column in the Specify Update Properties
dialog box, you tell PowerBuilder to bring back the value of a new
row’s identity column after an insert in the DataWindow object so
that users can see it.
For information about identity columns in
your DBMS, see your DBMS documentation.