Using Native Sequencing

Oracle, Sybase, SQL Server, and Informix databases support native sequencing in which the DBMS generates the sequence numbers. However, the TopLink Mapping editor must still tell the DBMS to assign sequence number values.

For Oracle databases, create a SEQUENCE object in the database.
For Sybase and SQL Server databases, set the primary key field to IDENTITY.
For Informix databases, set the primary key field to use SERIAL.
Tip: If you use native sequencing in these databases, TopLink cannot support preallocation. Oracle recommends using the sequence table instead. Oracle databases support preallocation, but only if the sequence increment matches the preallocation size. See "Preallocating Sequence Numbers" for more information.