text .vs. varchar

In response to Joao Ferreira <jmcferreira@critical-links.com>:

Hello all,

I have a big database in which much information is stored in TEXT type
columns (I did this initially because I did not want to limit the
maximum size of the string to be stored)... but...

.. let's say I choose an upper limit (p.ex. 200) for the string sizes
and I start a fresh database with VARCHAR(200).

What tradeoffs can I expect ? disk usage ? query execution times ?

See the "Tip" on this page, it answers your questions:
http://www.postgresql.org/docs/8.3/static/datatype-character.html

--
Bill Moran
Collaborative Fusion Inc.
http://people.collaborativefusion.com/~wmoran/

wmoran@collaborativefusion.com
Phone: 412-422-3463x4023

With Postgres appears that TEXT is preferred over varchar(N)
http://archives.postgresql.org/pgsql-general/2006-03/msg01522.php

Any other DB (e.g. Oracle) would suggest varchar as column only stores the length of the variable (variable character length..) vs any of the fixed length datatype(s)

Anyone else?
Martin
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Date: Wed, 13 Aug 2008 08:45:19 -0400
From: wmoran@collaborativefusion.com
To: jmcferreira@critical-links.com
CC: pgsql-general@postgresql.org
Subject: Re: [GENERAL] text .vs. varchar

In response to Joao Ferreira <jmcferreira@critical-links.com>:

Hello all,

I have a big database in which much information is stored in TEXT type
columns (I did this initially because I did not want to limit the
maximum size of the string to be stored)... but...

.. let's say I choose an upper limit (p.ex. 200) for the string sizes
and I start a fresh database with VARCHAR(200).

What tradeoffs can I expect ? disk usage ? query execution times ?

See the "Tip" on this page, it answers your questions:
http://www.postgresql.org/docs/8.3/static/datatype-character.html

--
Bill Moran
Collaborative Fusion Inc.
http://people.collaborativefusion.com/~wmoran/

wmoran@collaborativefusion.com
Phone: 412-422-3463x4023

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Martin Gainty wrote:

With Postgres appears that TEXT is preferred over varchar(N)
http://archives.postgresql.org/pgsql-general/2006-03/msg01522.php

Implementation-wise, they are exactly the same, modulo length checking.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.