Re: Unique and Primary Key Constraints - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Unique and Primary Key Constraints
Date
Msg-id 200207131429.g6DETSM21306@candle.pha.pa.us
Whole thread Raw
In response to Re: Unique and Primary Key Constraints  (Rod Taylor <rbt@zort.ca>)
Responses Re: Unique and Primary Key Constraints  (Rod Taylor <rbt@zort.ca>)
List pgsql-hackers
Rod Taylor wrote:
> > > I prefer ...add constraint.  After a while (release or 2) removal of
> > > create unique index all together.
> > 
> > Remove CREATE UNIQUE INDEX entirely?  Why?
> 
> I was looking to encourage users to use core SQL as I spend more time
> than I want converting between systems -- thanks in part to users who
> create non-portable structures.
> 
> Temporarily forgot there are index types other than btree :)

Not so much non-btree, but non-unique indexes themselves.  UNIQUE index
is funny because it is a constraint and an performance utility.  I see
your point that a constraint is more ANSI standard, but because we can't
get rid of non-unique indexes, I am not sure if there is really a good
reason to move to UNIQUE constraints.  Well, it does make the table
definition and index more compact (one statement) but we split them up
on pg_dump so we can load the table without the index, so it doesn't
seem to be a win.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
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