If you create a sequence attached to a column in a DBMS supporting sequences, such as Oracle 8 and higher, Interbase or PostgreSQL, or create an auto-incremented column in a DBMS supporting this feature, and then decide to change the target DBMS, the following effects occur:
|
DBMS change |
Defined in original DBMS |
Effect on sequence objects and auto-incremented columns |
|---|---|---|
|
DBMS supporting sequences to a DBMS supporting auto-incremented columns |
Sequence attached to a column |
The sequence disappears and the column to which it was attached becomes an auto-incremented column in the DBMS |
|
DBMS supporting auto-incremented columns to a DBMS supporting sequences |
Auto-incremented column |
The auto-incremented column is deleted and replaced by a sequence object called S_TABLENAME which is attached to the original column |