Creating a MYSQL Trigger using PDO / PHP

I've been trying to create a trigger within PHP / PDO. I need to use session variables, and only know how to handle them on PHP, hence this was my start point.

My query is as follows:-

$updateTrigger = "DROP TRIGGER IF EXISTS `trigger_repair_update` ;
CREATE TRIGGER `trigger_repair_update` BEFORE UPDATE ON $tbl_name
FOR EACH ROW
BEGIN
IF (NEW.repaired_by != OLD.repaired_by) THEN
INSERT INTO data_tracking
(`table_name` , `data_id`, `field`, `old_value` , `new_value` , `date_modified`, `username`)
VALUES
('$tbl_name' , NEW.id , 'repaired_by' , OLD.repaired_by , NEW.repaired_by , NOW() , '$user' );
END IF;
IF (NEW.must_have != OLD.must_have) THEN
INSERT INTO data_tracking
(`table_name` , `data_id`, `field`, `old_value` , `new_value` , `date_modified`, `username`)
VALUES
('$tbl_name' , NEW.id , 'must_have' , OLD.must_have , NEW.must_have , NOW() , '$user' );
END IF;
IF (NEW.location != OLD.location) THEN
INSERT INTO data_tracking
(`table_name` , `data_id`, `field`, `old_value` , `new_value` , `date_modified`, `username`)
VALUES
('$tbl_name' , NEW.id , 'location' , OLD.location , NEW.location , NOW() , '$user' );
END IF;
IF (NEW.status != OLD.status) THEN
INSERT INTO data_tracking
(`table_name` , `data_id`, `field`, `old_value` , `new_value` , `date_modified`, `username`)
VALUES
('$tbl_name' , NEW.id , 'status' , OLD.status , NEW.status , NOW() , '$user' );
END IF;
IF (NEW.price != OLD.price) THEN
INSERT INTO data_tracking
(`table_name` , `data_id`, `field`, `old_value` , `new_value` , `date_modified`, `username`)
VALUES
('$tbl_name' , NEW.id , 'price' , OLD.price , NEW.price , NOW() , '$user' );
END IF;
END;";

$sth = $dbLink->prepare($updateTrigger);
$sth->execute();

If I remove the variables and enter into PHPMYADMIN, everything works fine, so my conclusion is that I have not allocated the variables properly. Should I be binding parameters here?

I've looked in many places for this:

• http://code.tutsplus.com/articles/introduction-to-mysql-triggers--net-12226
• Is is possible to see what data was changed by a query?
• Using MySQL triggers to log all table changes to a secondary table
• Is there a MySQL option/feature to track history of changes to records?
• http://codespatter.com/2008/05/06/how-to-use-triggers-to-track-changes-in-mysql/

I still seem to be missing something though.

EDIT:- Thanks to Michael Berkowski, I have added the error code and get the following message:-

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'CREATE TRIGGER trigger_repair_update BEFORE UPDATE ON repair FOR EACH ROW BEGI' at line 2' in /Applications/MAMP/htdocs/repair_list.php:58 Stack trace: #0 /Applications/MAMP/htdocs/repair_list.php(58): PDO->prepare('DROP TRIGGER IF...') #1 {main} thrown in /Applications/MAMP/htdocs/repair_list.php on line 58

Line 58 is where the $sth = $dbLink->prepare($updateTrigger); sits.