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

Just to throw in my own issue in case it can help someone else, I was copy/pasting entries in my migration files and messed up by putting quotes around an integer. Since the value I was trying to enter was considered a string going into an integer field that was referencing another integer, this error came up.