Hi,

Is it possible to have a varchar column unique without indexing it?
My table looks like this:
CREATE TABLE `tbladvert` (
`adId` int(11) unsigned NOT NULL auto_increment,
`adSubject` varchar(150) NOT NULL default '',
`adDate` date NOT NULL default '0000-00-00',
`adImage` tinyint(1) NOT NULL default '0',
`adType` tinyint(1) NOT NULL default '0',
`adFrom` varchar(50) NOT NULL default '',
`adURL` varchar(255) NOT NULL default '',
PRIMARY KEY (`adId`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

I would like to make adURL unique.

//M

no, it's not, because that's how mysql implements unique constraints

what's wrong with indexing it?

Hi,

Thank you for the quick answer. It's no wrong with indexing it, except for I've heard that the more index you have in a table the slower the table will be to search in. Is it true?

//M

that's just a general rule, but in your case having a unique index is actually a very good idea, since you have a surrogate (auto_increment) primary key

Ok!
I'll need to search on adImage and adType in my table, should I index them aswell?

//M