sequence| PSEUDO columns | CURRVAL| NEXTVAL| LEVEL| ROWNUM| ROWID
Sequence Pseudo columns à Pseudo column behave like a table column, but it is not actually store in a table. à Upon pseudo column only select can be possible, DML operations can’t be possible to implement. à The available pseudo columns are 1. CURRVAL 2. NEXTVAL 3. LEVEL 4. ROWNUM 5. ROWID à CURRVAL, NEXTVAL are applied upon sequence schema object. These are only in select statement, value clause of insert statement, set clause of update statement. à CURRVAL, NEXTVAL can’t be used in · A sub queries · A view, SNAPSHOT query · Select statement with group by or order by · Select statement with distinct operation. · ...