Is there any way to make a UNIQUE index case insensitive in Mysql 5.1.x ?

Question

If so - What must change in this table ?

CREATE TABLE  contestants 
( 
  idContestants  int(10) unsigned NOT NULL AUTO_INCREMENT,
  idEvent        int(10) unsigned NOT NULL,
  ContestantName  varchar(50) DEFAULT NULL,
  PRIMARY KEY (idContestants),
  UNIQUE KEY Index_UniqueName (idEvent,ContestantName),
)
ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=latin1;

Barnes

What does 'case instinctive' mean? – Gautier

Do you mean case insensitive? – Blanka

Answer 1

If you mean case sensitive then:

ALTER TABLE `contestants` CHANGE `ContestantName` `ContestantName` VARCHAR( 50 )
CHARACTER SET latin1 COLLATE latin1_bin NULL DEFAULT NULL 

If you mean case insensitive then:

ALTER TABLE `contestants` CHANGE `ContestantName` `ContestantName` VARCHAR( 50 )
CHARACTER SET latin1 COLLATE latin1_general_ci NULL DEFAULT NULL 

For table level do (for case insensitive):

ALTER TABLE `contestants` DEFAULT CHARACTER SET latin1 COLLATE latin1_general_ci

Note that table level only affects new columns.

For database level do (for case insensitive):

ALTER DATABASE `database_name` CHARACTER SET latin1 COLLATE latin1_general_ci

Note that database level only affect new tables.

Gautier

It is important to note that this is a COLUMN level collation, initially I read this too quickly and thought it was a TABLE level collation which didn't work for me. – Choral

@ScottJungwirth I added info about changing it at table and database level. – Gautier

Answer 2

Yes, use a case-insensitive collation on the columns involved.

MySQL Manual :: Column Character Set and Collation

Bacchanalia

Answer 3

This worked for me in Mysql 5.5

ALTER TABLE `contestants` MODIFY
`ContestantName` VARCHAR(50) 
CHARACTER SET latin1
COLLATE latin1_bin;

Cinder