Re: Quick Help
От | Rod Taylor |
---|---|
Тема | Re: Quick Help |
Дата | |
Msg-id | 1039134028.72042.8.camel@jester обсуждение исходный текст |
Ответ на | Quick Help ("Christopher Kings-Lynne" <chriskl@familyhealth.com.au>) |
Список | pgsql-hackers |
It works very similarly to the way that ALTER TABLE ... ADD CHECK .. works, with the tuple update added in. Anyway, it's something like the below: - Lock relation - Pull out tuple - Evaluate cooked default expression using EvalExpr - heap_modifytuple (shove datum that EvalExpr returns into column) - simple_heapupdate - Goto step 2 (pull out next tuple) On Thu, 2002-12-05 at 16:24, Christopher Kings-Lynne wrote: > Hi guys, > > Messing about with ADD COLUMN... > > I'm not certain how to re-evaluate the default expression for each row? How > do I do this? I have access to raw_default and cooked_default it seems. > > Thanks, > > Chris > > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster -- Rod Taylor <rbt@rbt.ca> PGP Key: http://www.rbt.ca/rbtpub.asc
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