Re: Differences between postgres and mysql - Mailing list pgsql-general

From Richard Huxton
Subject Re: Differences between postgres and mysql
Date
Msg-id 200402181246.37735.dev@archonet.com
Whole thread Raw
In response to Differences between postgres and mysql  ("Mark Cubitt" <mark.cubitt@applegate.co.uk>)
List pgsql-general
On Wednesday 18 February 2004 11:50, Mark Cubitt wrote:
> the reason I ask is I have always used postgres at home and work, but my
> new web host only has mysql :(
>
> I want to know what sort of differences I will have in regards to
> programming php/perl webpages using the database.

Perhaps your best bet is to go over to http://techdocs.postgresql.org and
check out the porting sections.

> I current use sequences in postgres and understand this will be different
> in mysql, so can you tell me what the difference will be and if there are
> any other differences I should look out for.

Hmm... assuming MySQL 3.x (likely in a hosted environment I'd have thought)
 - no UNION
 - no sub-queries (iirc)
 - no views
 - no foreign-keys
 - sloppy datatyping if you're feeling strict, simplified checking if you're
feeling generous
 - actually, silently fails on a number of operations (data validation,
foreign key creation etc).
 - no triggers/procedural languages
 - only one sequence per table (typed as autonumber)
 - no transactions on ISAM tables
 - performance can fall off rapidly with multiple writers
 - I don't think you can do a hot backup with the transaction-based storage
libraries

In it's defence:
 - SELECT count(*) FROM foo; can run much faster
 - Other simple queries also perform well

There are hosting companies who will do PG for a reasonable price - is it
worth the pain of switching?

--
  Richard Huxton
  Archonet Ltd

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