Question

I have a website which I have been working on creating very rapidly, and now am paying back some technical debt. I have a complicated issue:

My site deals with scheduling hikes. Once you create a hike, it has many things associated with it:
a message board, list of attendees, the group it belongs to, the carpool, route, trailhead, etc.

Here is an example so you can see what I am talking about:
http://www.comehike.com/hikes/scheduled_hike.php?hike_id=172

The technical debt I am talking about is that I never made foreign keys in the DB, and now need to do a cascade delete, and I am not sure how to go about it so that I don’t introduce a million bugs 🙂

Should I make foreign keys for all the tables now? How should I do this?

Thanks,
Alex

Answer 1

Check out the MySQL docs on FOREIGN KEY Constraints. Note that you’ll need to be using innoDB tables.

ALTER TABLE <tablename>
ADD CONSTRAINT <fkname> FOREIGN KEY <index name>(<columns>)
REFERENCES <othertable> (<columns>)
ON DELETE CASCADE