How to re-index a linked table?

Question

MySQL

How to re-index a linked table?
I have table A and it is related to table B many-to-many, how is re-indexing done in this case?

Thought like this:

ALTER TABLE A ADD COLUMN id2 int unsigned not null;
SET @a:=0;
UPDATE A SET [email protected]:[email protected]+;
ALTER TABLE A DROP id;

But naturally it will not let you do it because of the connection.

Answer 1

Change immediately idby setting ON UPDATE CASCADE first .