How to prevent a stored procedure user from skipping zero?

Question

I am writing a simple MySQL stored procedure:

DELIMITER $ DROP PROCEDURE IF EXISTS GetUserByCaseId $ CREATE DEFINER = 'DEV_Organization'@'localhost' PROCEDURE GetUserByCaseId (IN searchedForId VARCHAR(8)) LANGUAGE SQL NOT DETERMINISTIC READS SQL DATA SQL SECURITY DEFINER BEGIN SELECT CaseIdAuthenticator.sid AS sid, CaseIdAuthenticator.caseId AS caseId, User.firstName AS firstName, User.lastName AS lastName, User.position AS position, User.email AS email FROM CaseIdAuthenticator INNER JOIN User ON User.sid = CaseIdAuthenticator.sid WHERE CaseIdAuthenticator.caseId = searchedForId LIMIT 1; END $ 

It works:

 mysql> CALL DEV_Organization.GetUserByCaseId("bro4"); +------+--------+-----------+----------+----------+----------------------+ | sid | caseId | firstName | lastName | position | email | +------+--------+-----------+----------+----------+----------------------+ | 3773 | bro4 | Billy | O'Neal | | [e-mail] | +------+--------+-----------+----------+----------+----------------------+ 1 row in set (0.00 sec) 

but unfortunately, allows the client to leave with NULL passing:

 mysql> CALL DEV_Organization.GetUserByCaseId(NULL); Empty set (0.00 sec) 

I would rather throw an error instead. How can i do this? (Just setting it to VARCHAR(8) NOT NULL causes MySQL to throw an error when creating the procedure ...)

EDIT: Commentators have asked for my rationale. I am working with a database API in PHP land that looks like this:

 /** * Inside function which is used to implement other procedure functions. * * @param string $suffix The database schema suffix. * @param string $procedure The name of the procedure that should be executed. * @param array $arguments A set of arguments which should be passed to the stored procedure. * @return PDOStatement The PDOStatement generated by sending the query to the MySQL Server. */ private function ProcedureInner($suffix, $procedure, $arguments = array()) { $suffix = (string)$suffix; $procedure = (string)$procedure; $questionMarks = ''; $args = count($arguments); if ($args > 0) { $questionMarks = '?'; for ($idx = 1; $idx < $args; ++$idx) { $questionMarks .= ', ?'; } } $stmt = $this->pdo->prepare("CALL `{$this->mode}_{$suffix}`.`{$procedure}` ({$questionMarks})"); $stmt->execute($arguments); return $stmt; } /** * Executes a stored procedure which returns a single value in a single row. * * @param string $schema The suffix of the schema where the procedure is located. * @param string $procedure The name of the procedure to call. * @param array $arguments Arguments to supply to the procedure, if any. * @return mixed The content of the value. */ public function ProcedureScalar($schema, $procedure, $arguments = array()) { $result = $this->ProcedureInner($schema, $procedure, $arguments); $answer = $result->fetchColumn(0); $result->closeCursor(); return $answer; } 

notice how easy it is for the client to forget to pass an argument in an array of arguments However, this is the low-level part of database abstraction, I do not want to put the constraints that certain arguments look for here.

Answer 1

MySQL 5.5 and later versions of SIGNAL for this purpose (to raise arbitrary exceptions in user routines):

 .... BEGIN IF searchedForId IS NULL THEN SIGNAL SQLSTATE '45000' -- unhandled user-defined exception SET MESSAGE_TEXT = 'Parameter may not be NULL'; END IF; SELECT CaseIdAuthenticator.sid AS sid, ....