php constraint violation Error 1452

Question

Good morning, i have a big problem with this sql error when i,m trying to insert a event in my database with this pdo:

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SQL:

$subsquery1 = \"SELECT cat_id         


        

Answer 1

Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (datenbank.events, CONSTRAINTevents_ibfk_1FOREIGN KEY (event_cat) REFERENCEScategories(cat_id)

You are performing an insert to table events with a value being placed in column event_cat.

That value does not already exist in table categories in the column cat_id.

And you said it must. So the db engine says it won't do it. It is faithfully obeying your orders.