Add foreign key in phpmyadmin

Question

Following images are my table structure and the relational view form in phpmyadmin

My question is how to add foreign key for 'org_id' column, 'org_id' is also an integer field and it's unsigned field but why it isn't allow to add a foreign key.

Answer 1

MySQL forces you to index foreign key.

MySQL requires indexes on foreign keys and referenced keys so that foreign key checks can be fast and not require a table scan.

You can read more about foreign keys on MySQL documentation pages: http://dev.mysql.com/doc/refman/5.7/en/create-table-foreign-keys.html

Answer 2

Just had to figure this out for myself:

• Open the table you want to add foreign keys too.

• Click the Structure Tab

• Click the RELATION VIEW button just above the list of columns

• Enter data for in the Foreign key constraints box

• DO NOT index the column you want to make into a Foreign Key first. This caused my creation attempts to fail

Answer 3

父表中的 org_id 应该被索引，所以只需在父表中创建索引，然后创建外键。