From: | Hannu Krosing <hannu(at)tm(dot)ee> |
---|---|
To: | Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp> |
Cc: | Don Baccus <dhogaza(at)pacifier(dot)com>, PostgreSQL Development <pgsql-hackers(at)postgreSQL(dot)org>, Peter Eisentraut <peter_e(at)gmx(dot)net> |
Subject: | Re: Happy column adding (was RE: [HACKERS] Happy column dropping) |
Date: | 2000-01-26 08:45:42 |
Message-ID: | 388EB436.8AE7334F@tm.ee |
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Lists: | pgsql-hackers |
Hiroshi Inoue wrote:
>
> > However, heap_getattr still won't see the default since it simply
> > checks to see of the attribute number falls off the end of the
> > tuple and then returns null.
> >
>
> Sorry,the following question might be already answered but too
> many postings for me.
>
> Do we have to refer default value for already inserted rows ?
> Doesn't 'default' have its meaning only when rows are about to be
> inserted ?
I think the case was about adding a NOT NULL column and setting current NULL
columns to DEFAULT seemed like a natural thing to do.
But, considering the fact that DEFAULT can be something reaaly complex, like
function that does a lot of things, it may be better to have the constraints
checked at the end of transaction, like
BEGIN;
ALTER TABLE T1 ADD COLUMN C1 TEXT NOT NULL;
UPDATE T1 SET C1='MYDEFAULTVALUE';
COMMIT;
only IIRC we have quite poor support for DDL statements inside transactions.
---------------
Hannu
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