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.
