MySQL Error 1452 - Cannot add or update?

This is my database:

http://i.imgur.com/D1M4J.png

I am trying to insert data into my main linking table procedure after inserting data into all the tables around it. I have checked the data being inserted and it seems ok, I have checked my relationships as well.

$proceduredata = array 
            (
                'patient_id' => $patientfk,
                'name_id' => $procedurenamefk,
                'department_id' => $departmentfk,
                'dosage_id' => $dosagefk,
                'edocument' => NULL, //not implemented yet
                'user_id' => $this->session->userdata('userID'),
                'duration' => NULL, //not implemented yet
                'submitted' => date('d-m-Y H:i:s', now()),
                'comment' => NULL, //to be implemented

            );

            $insertprocedure = $this->db->insert('procedure', $proceduredata); //inserts into 'procedure' table with $proceduredata array
            $procedurefk = $this->db->insert_id(); //gets the primary key of the row inserted

The error message:

A Database Error Occurred

Error Number: 1452

Cannot add or update a child row: a foreign key constraint开发者_开发百科 fails (midas1.procedure, CONSTRAINT belongs to a FOREIGN KEY (department_id) REFERENCES department (department_id))

INSERT INTO procedure (patient_id, name_id, department_id, dosage_id, edocument, user_id, duration, submitted, comment) VALUES (17, 7, 0, NULL, NULL, '2', NULL, '06-07-2011 13:41:01', NULL)

Filename: C:\xampp\htdocs\midas\system\database\DB_driver.php

Line Number: 330

Thanks for your time

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$departmentfk seems to be 0, but needs to be an ID from the department table, according to your constraints in MySQL. MySQL checks the department table and doesn't find a corresponding ID, thats why it fails.