For implementing identifier value generation based on IDENTITY columns, Hibernate makes use of its org.hibernate.id.IdentityGenerator id generator which expects the identifier to generated by INSERT into the table. IdentityGenerator understands 3 different ways that the INSERT-generated value might be retrieved:

* If Hibernate believes the JDBC environment supports java.sql.Statement#getGeneratedKeys, then that approach will be used for extracting the IDENTITY generated keys.

* Otherwise, if Dialect#supportsInsertSelectIdentity reports true, Hibernate will use the Dialect specific INSERT+SELECT statement syntax.

* Otherwise, Hibernate will expect that the database supports some form of asking for the most recently inserted IDENTITY value via a separate SQL command as indicated by Dialect#getIdentitySelectString