artijn/
> Database development questions? Check the forum!
> http://www.databasedevelopmentforum.com
>
> -Noah
>
>
> -Original Message-
> From: Kristian Myllymäki [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, August 14, 2007 3:50 AM
> To: Ananda Kumar
> Cc: Jame
ijn/
Database development questions? Check the forum!
http://www.databasedevelopmentforum.com
-Noah
-Original Message-
From: Kristian Myllymäki [mailto:[EMAIL PROTECTED]
Sent: Tuesday, August 14, 2007 3:50 AM
To: Ananda Kumar
Cc: James Tu; MySQL List
Subject: Re: index, unique index questi
3:50 AM
To: Ananda Kumar
Cc: James Tu; MySQL List
Subject: Re: index, unique index question
A composite index on both columns may be used by queries involving
either both columns, or the first column in the index.
http://dev.mysql.com/doc/refman/5.0/en/multiple-column-indexes.html
So, an index
A composite index on both columns may be used by queries involving
either both columns, or the first column in the index.
http://dev.mysql.com/doc/refman/5.0/en/multiple-column-indexes.html
So, an index on (receiver_id, sender_id) may be used by predicates on
both columns or receiver_id al
Hi James,
Since your queries have both receiver_id and sender_id in the where
condition and u want this to be unique, just create one combined unique
index on both these columns.
Do this at db level will give you much better options, performance, rather
than doing at code level, which might involv
> on a related but slightly different example, what would happen if you had a
> Primary Key consisting of 2 columns a & b (so the pkey enforces a unique
> combination of a & b) and then created an index on one of the columns eg b.
> Would the index on b have any effect, or does a primary key on 2
; [EMAIL PROTECTED]
Subject: Re: INDEX() / UNIQUE()
Why would you want to? UNIQUE() is an INDEX() the only difference being
that UNIQUE can not have the same value a number of times whereas INDEX you
can.
- Original Message -
From: "Jacob Friis Larsen" <[EMAIL PROTECTED]&g
Why would you want to? UNIQUE() is an INDEX() the only difference being
that UNIQUE can not have the same value a number of times whereas INDEX you
can.
- Original Message -
From: "Jacob Friis Larsen" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, February 06, 2001 21:38
Subj
