SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails

Question

I am trying to insert values into my comments table and I am getting a error. Its saying that I can not add or update child row and I have no idea what that means. My schema

Answer 1

It just simply means that the value for column country on table comments you are inserting doesn't exist on table country_type or you are not inserting value for country on table user. Bear in mind that the values of column country on table comments is dependent on the values of ID on table country_type.