ORA_ROWSCN Pseudocolumn

For each row, ORA_ROWSCN returns the conservative upper bound system change number (SCN) of the most recent change to the row. This pseudocolumn is useful for determining approximately when a row was last updated. It is not absolutely precise, because Oracle tracks SCNs by transaction committed for the block in which the row resides. You can obtain a more fine-grained approximation of the SCN by creating your tables with row-level dependency tracking. Please refer to CREATE TABLE ... NOROWDEPENDENCIES | ROWDEPENDENCIES for more information on row-level dependency tracking.

You cannot use this pseudocolumn in a query to a view. However, you can use it to refer to the underlying table when creating a view. You can also use this pseudocolumn in the WHERE clause of an UPDATE or DELETE statement.

ORA_ROWSCN is not supported for Flashback Query. Instead, use the version query pseudocolumns, which are provided explicitly for Flashback Query. Please refer to the SELECT ... flashback_query_clause for information on Flashback Query and "Version Query Pseudocolumns" for additional information on those pseudocolumns.

Restriction: This pseudocolumn is not supported for external tables.

Example The first statement below uses the ORA_ROWSCN pseudocolumn to get the system change number of the last operation on the employees table. The second statement uses the pseudocolumn with the SCN_TO_TIMESTAMP function to determine the timestamp of the operation:

SELECT ORA_ROWSCN, last_name FROM employees WHERE employee_id = 188;

   WHERE employee_id = 188;

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