我无法在PHPmyadmin XAMPP中设置外键

Question

When i need to set a field as the foreign key in a table,in PHPMyAdmin. I am not getting it set right.

There is a Parent table called 'user' which has a primary key called 'uid'.I am using the 'uid' in the child table called 'student_register' as foreign key. But while setting it as foreign key constraint through the relation view link in phpmyadmin . i am not able to see the 'user' table in the drop down list to select it and set the 'uid' as foreign key .. I have sent the screen shot to get a clear picture. the screenshot for the phpmyadmin child table 'student_register'

Answer 1

You should add index to the column uid in table user in order to appear in the drop down list

Take the structure of table user , then click the last option of the Action - Add index for the column uid.

Answer 2

From the MYSQL User Guide:

If you are facing this issue than you need to follow these basic steps:

1. Database storage engine must be InnoDB .
2. Your relational tables must be InnoDB .
3. Use UNIQUE reference key.
4. Reference Key can not be NULL .
5. Datatype of the both columns must be same.

References:

Create Table Foreign Keys in MYSQL

Creating Foreign Key Relationships