I've created a materialized view in an Oracle 18c database.
When I look at the Info tab of the materialized view in Toad, I see that there is a property called Update Trigger.
What does the Update Trigger property represent?
materialized-vieworacleoracle-18ctrigger
Best Answer
Those are the remains of an ancient feature called updatable snaphots that later became updatable materialized views.
Originally materialized views were called snapshots. The values for
Update Trigger
andUpdate Log
come from theUPDATE_TRIG
andUPDATE_LOG
columns ofALL|DBA|USER_SNAPSHOTS
, a view that was last documented properly in Oracle 8i: ALL_SNAPSHOTS. The 9.0 documentation of that view is actually broken.Oracle 7: Snapshot Site Replication
In Oracle 8i, snapshots were renamed to materialized views, and updatable snapshots became updatable materialized views. The above allowed users to perform DML operations on snapshots/materialized views, and those changes could be replicated back to the master tables.
Updatable materialized views were part of a feature called Advanced Replication. That is a feature that I have yet to see in a real database. About 6 years ago I found a 10.2 customer database in which someone tried to set up this feature in 2008 but failed to do it. I have never ever seen this anywhere else.
Advanced Replication became deprecated in 12.1, and desupported in 12.2.