-On [20030911 15:43], Tom Lane (tgl@sss.pgh.pa.us) wrote:
>We can't ALTER a table that's already in use when the first ALTER
>starts, either --- its attempt to exclusive-lock the table will fail.
>But once you get the exclusive lock, you can (in Postgres) perform
>a series of operations without fear that subsequently-started
>transactions will be able to see the incompletely changed state of the
>table. Evidently Oracle can't handle that. That's why they need to
>invent combination operations like MODIFY CONSTRAINT.
As my colleague says:
it is indeed a lazy choice, but super safe and that's the goal.
--
Jeroen Ruigrok van der Werven <asmodai(at)wxs.nl> / asmodai / kita no mono
PGP fingerprint: 2D92 980E 45FE 2C28 9DB7 9D88 97E6 839B 2EAC 625B
http://www.tendra.org/ | http://www.in-nomine.org/~asmodai/diary/
Man inagines that it is death he fears; but what he fears is the unforeseen,
the explosion. What man fears is himself...