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Re: size of varchar

From: Richard Broersma Jr <rabroersma(at)yahoo(dot)com>
To: Andreas <maps(dot)on(at)gmx(dot)net>, pgsql-novice(at)postgresql(dot)org
Subject: Re: size of varchar
Date: 2007-03-23 04:55:09
Message-ID: 633525.74741.qm@web31807.mail.mud.yahoo.com (view raw or flat)
Thread:
Lists: pgsql-novice
> Therefore I have never figured out the really necessary size for 
> zip-codes, names, phone numbers and what not.
> 
> Can I stay with size 255 in PG without getting a space- or speed-penalty ?
> I'll use ODBC. Is the size 255 relevant in network transfers ?

you probably can, I don't see how it would hurt. However, in postgres you don't even need to
specify a size for your varchar field.

from:
http://www.postgresql.org/docs/8.2/interactive/datatype-character.html

"
If you desire to store long strings with no specific upper limit, use text or character varying
without a length specifier, rather than making up an arbitrary length limit.) 

Tip: There are no performance differences between these three types, apart from the increased
storage size when using the blank-padded type. While character(n) has performance advantages in
some other database systems, it has no such advantages in PostgreSQL. In most situations text or
character varying should be used instead. 
"

However, I do not recommend for programs like access or crystal reports.  They cast the types as a
MEMO field.  Reports can groupby these unbounded varchar field.  So it is better to put limits on
them. However, of you never intend to do anything other than store text, it probably would hurt.

Regards,
Richard  Broersma Jr.

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