Re: Getting lengths of variable fields - Mailing list pgsql-general

From Peter Eisentraut
Subject Re: Getting lengths of variable fields
Date
Msg-id Pine.LNX.4.30.0103052338120.777-100000@peter.localdomain
Whole thread Raw
In response to Getting lengths of variable fields  (Michelle Murrain <mpm@norwottuck.com>)
Responses Re: Getting lengths of variable fields  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
Michelle Murrain writes:

> I'm writing a very robust validation script in perl for database entry. One
> of the things I'd like to do is check how large a field is, and make sure
> that the entry into that field isn't too big. Problem is, for variable length
> fields, DBD::Pg returns a -1 size, using the pg_size attribute.
>
> Is there something I am missing? Is there a way to get the size of variable
> length types using DBI/DBD::Pg, in particular, char() and varchar()?

Normally, you'd use LENGTH or OCTET_LENGTH.  If you want to get the
storage size on disk, you could add 4 to what you get as length, but this
result seems to be of dubious value, especially with TOAST (compression,
out-of-line storage).

--
Peter Eisentraut      peter_e@gmx.net       http://yi.org/peter-e/


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