what is use of 'KEY' in mysql , it is not allowing me edit record in phpmyadmin

Question

Here is my database mapping table definition, you can try this, when I create this table and add some records in to it, it is not let me edit or delete the records by phpmyadmin although by query it should be possible,

CREATE TABLE IF NOT EXISTS `map2` (
  `map_table_a` varchar(25) DEFAULT NULL,
  `map_id_a` int(10) DEFAULT NULL,
  `map_table_b` varchar(25) DEFAULT NULL,
  `map_id_b` int(10) DEFAULT NULL,
 KEY `map_table_b` (`map_table_b`,`map_id_b`),
 KEY `map_table_a` (`map_table_a`,`map_id_a`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

I don't know reason behind this behavior

@Manwal I don't know, people are saying it is equal to INDEX in mysql — Chintan Gor, Jan 20 '15 at 10:16
See this: http://dev.mysql.com/doc/refman/5.5/en/optimization-indexes.html — Manwal, Jan 20 '15 at 10:17
@Manwal Sir I know index, But my actual question is why I can't edit records by PHPMYADMIN , you can try to create this table and check — Chintan Gor, Jan 20 '15 at 10:19
You can see this post: http://stackoverflow.com/questions/924265/what-does-the-key-keyword-mean — Hardik Patel, Jan 20 '15 at 10:19
@HardikPatel my question is different then "What does the KEY keyword mean?" — Chintan Gor, Jan 20 '15 at 10:21
@ChintanGor define a `Primary Key` in your table. Then you will able to edit record from Phpmyadmin. — Manwal, Jan 20 '15 at 10:22
Reopened due to absolutely not being a duplicate of the marked question. — Niet the Dark Absol, Jan 20 '15 at 11:41

score 3 · Accepted Answer · answered Jan 20 '15 at 10:48

Depending on your phpMyAdmin version, you should see this error message:

This table does not contain a unique column. Grid edit, checkbox, Edit, Copy and Delete features are not available.

While you do have KEY columns, you have no PRIMARY or UNIQUE columns defined. This is why phpMyAdmin cannot edit your data - it has no way to be sure it is editing the correct row.

Suggested solution: Add the following into your table definition, preferably as the first column:

`id` INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY

what is use of 'KEY' in mysql , it is not allowing me edit record in phpmyadmin

1 Answers1