Re: [PERFORM] Clarification, please

2010-12-01 Thread Kevin Grittner
Mladen Gogala wrote: > How is it possible to insert the same value twice into a UNIQUE > index? You get multiple entries for the same value in a UNIQUE indexes all the time in PostgreSQL. Any non-HOT update of a table with a UNIQUE index will cause that. You just can't have duplicate entries

Re: [PERFORM] Clarification, please

2010-12-01 Thread Mladen Gogala
Richard Broersma wrote: It looks like the check isn't preformed until COMMIT. So, the index is not actually updated until commit? H, that seems unlikely. -- Mladen Gogala Sr. Oracle DBA 1500 Broadway New York, NY 10036 (212) 329-5251 http://www.vmsinfo.com The Leader in Integrated

Re: [PERFORM] Clarification, please

2010-12-01 Thread Richard Broersma
On Wed, Dec 1, 2010 at 8:46 AM, Mladen Gogala wrote: > PostgreSQL 9.0, however, creates a unique index: > >   scott=# create table test1 >   scott-# (col1 integer, >   scott(#  constraint test1_pk primary key(col1) deferrable); >   NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index >

[PERFORM] Clarification, please

2010-12-01 Thread Mladen Gogala
In Oracle, deferrable primary keys are enforced by non-unique indexes. That seems logical, because index should tolerate duplicate values for the duration of transaction: Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - Production With the Partitioning, OLAP, D