Set named restore points for easier flashback in Oracle 10gR2

Friday Mar 7th 2008 by DatabaseJournal.com Staff
Share:

The MERGE statement, introduced in Oracle 9i Release 2, is often called an "upsert" because it can both update and insert rows in the same pass.

[From Builder AU]

It's a real timesaver for Extract, Transform, and Load (ETL) applications, such as loading a data warehouse. Rows that don't already exist in the data warehouse are inserted, and rows that do exist are updated.

When the MERGE statement was introduced, both an UPDATE and an INSERT clause were required, and the order was fixed (first the UPDATE, then the INSERT). If you only wanted to do one or the other, you would use the existing INSERT or UPDATE statement instead of MERGE. Deletions were always done separately via the DELETE statement.

The article continues at http://www.builderau.com.au/program/oracle/soa/Set-named-restore-points-for-easier-flashback-in-Oracle-10gR2/0,339028441,339286555,00.htm

Share:
Home
Mobile Site | Full Site
Copyright 2017 © QuinStreet Inc. All Rights Reserved