Oracle Pseudocolumns : CURRVAL and NEXTVAL

CURRVAL and NEXTVAL

A sequence is a schema object that can generate unique sequential values. These values are often used for primary and unique keys. You can refer to sequence values in sql statements with these pseudocolumns:

CURRVAL

The CURRVAL pseudocolumn returns the current value of a sequence.

NEXTVAL

The NEXTVAL pseudocolumn increments the sequence and returns the next value.

You must qualify CURRVAL and NEXTVAL with the name of the sequence:

sequence.CURRVAL
sequence.NEXTVAL

To refer to the current or next value of a sequence in the schema of another user, you must have been granted either SELECT object privilege on the sequence or SELECT ANY SEQUENCE system privilege, and you must qualify the sequence with the schema containing it:

schema.sequence.CURRVAL
schema.sequence.NEXTVAL

To refer to the value of a sequence on a remote database, you must qualify the sequence with a complete or partial name of a database link:

schema.sequence.CURRVAL@dblink
schema.sequence.NEXTVAL@dblink

Oracle Pseudocolumns CURRVAL ,NEXTVAL,LEVEL,ROWID,ROWNUM

A pseudocolumn behaves like a table column, but is not actually stored in the table. You can select from pseudocolumns, but you cannot insert, update, or delete their values. This section describes these pseudocolumns:

* CURRVAL and NEXTVAL

* LEVEL

* ROWID

* ROWNUM