Adding constraints in phpMyAdmin

Question

I feel like I'm being stupid, but I can't find anywhere on the phpMyAdmin interface to add constraints to foreign keys e.g. CASCADE ON DELETE

I've looked for similar questions on here and on the phpMyAdmin wiki but I can't find anything about it.

I realise I could do this via the query interface, but I'd like to know how to do it through the graphical interface.

Answer 1

CASCADE

Whenever rows in the master (referenced) table are deleted (resp. updated), the respective rows of the child (referencing) table with a matching foreign key column will get deleted (resp. updated) as well. This is called a cascade delete (resp. update[2]).

RESTRICT

A value cannot be updated or deleted when a row exists in a foreign key table that references the value in the referenced table. Similarly, a row cannot be deleted as long as there is a reference to it from a foreign key table.

NO ACTION

NO ACTION and RESTRICT are very much alike. The main difference between NO ACTION and RESTRICT is that with NO ACTION the referential integrity check is done after trying to alter the table. RESTRICT does the check before trying to execute the UPDATE or DELETE statement. Both referential actions act the same if the referential integrity check fails: the UPDATE or DELETE statement will result in an error.

SET NULL

The foreign key values in the referencing row are set to NULL when the referenced row is updated or deleted. This is only possible if the respective columns in the referencing table are nullable. Due to the semantics of NULL, a referencing row with NULLs in the foreign key columns does not require a referenced row.

Answer 2

Firstly, you should choose storage engine as InnoDB.

Follow this way: click database_name -> More -> Designer

Answer 3

First, you should have your storage engine as InnoDB. Then select a table and go to 'Structure' tab.

Under the table you will see 'Relation view', click it. From there you could add constraints.