ON UPDATE CASCADE, ON DELETE CASCADE

Question

please how does this two works on two relational tables?

Answer 1

tnx

Answer 2

Let's assume that a parent and child table exists where the parent and child link back into one another on a KEY.

ON DELETE CASCADE on the parent key will delete all children that depend on that parent.

ON UPDATE CASCADE on a parent will update the referenced key in the child.

Personally, this is bad practice as it renders your table column's keys unreliable.