From: Josh Berkus <josh@agliodbs.com>
To: mallah@trade-india.com
Cc: pgsql-sql@postgresql.org
Subject: Re: Getting NEW and OLD in ordinary functions.
Date: Wed, 9 Apr 2003 12:13:57 -0700
Message-ID: <200304091213.57184.josh@agliodbs.com> (raw)
In-Reply-To: <1461.219.65.233.94.1049915353.squirrel@mail.trade-india.com>
References: <200304091551.02277.mallah@trade-india.com>
<200304091123.16123.josh@agliodbs.com>
<1461.219.65.233.94.1049915353.squirrel@mail.trade-india.com>
Rajesh,
> This was for simulating CHECK (column in ('A','B' , 'C')) ;
>
> I already have 5 FKEYS on that table dont' u feel fkeys for this
> purpose is an overkill?
> eg here the valid values can range from say 3 to 10 (small number)
> whereas FKEYS are capable to check in a very large set residing in
> another table.
> also fkeys makes updates and inserts slower (i feel)
The problem with CHECK constraints is:
1) If you forget what the range of valid values for the column is, you have to
dump the constraint definition to find out;
2) If you want to add a new valid value, you have to:
a. Freeze all data entry on the table
b. delete the constraint
c. replace the constraint
d. test that the new constraint does not bug out
e. restart database access
adding a new value to a reference list is *much* easier.
> another question i have seen CHECK traslating IN to a set of ORs
> does the same happen in pl/pgsql internally? and does it really matter
> for here for small target sets?
No idea, and probably not.
--
-Josh Berkus
Aglio Database Solutions
San Francisco
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To: pgsql-sql@postgresql.org
Cc: josh@agliodbs.com, mallah@trade-india.com
Subject: Re: Getting NEW and OLD in ordinary functions.
In-Reply-To: <200304091213.57184.josh@agliodbs.com>
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