Re: MERGE vs REPLACE

Jaime,

> why? seems that REPLACE only work if there are at least one row
> matching...

Scenario:

session1: REPLACE .... 1                            session2:  REPLACE ..... 1
session1: check to see that "1" exists .... no                 session2: check to see that "1" exists .... no
session1: INSERT 1                 session2: INSERT 1 .... ERROR

Get the picture?  The only way to avoid a race condition is to be able to 
do "predicate locking", that is to lock the table against any data write 
matching that predicate.

-- 
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco