INSERT statement conflicted with the FOREIGN KEY contraint

Question

Hi :)

I have 2 tables

Client(client_id(pk), first_name, last_name, user_id(fk))
User(user_id(pk), password, client_id(fk)). (my database is more complex, this is just an exemple).

And I'm trying to insert a new record in my database, but i just keep getting an error from the foreign key, because of the one to one relationship. I've tried to use a default value for user_id in client, but the same error. Does anybody know how to solve this pb? please :(