Using simple stored procedures

You can create and call stored procedures in embedded SQL.

You can embed a CREATE PROCEDURE just like any other data definition statement, such as CREATE TABLE. You can also embed a CALL statement to execute a stored procedure. The following code fragment illustrates both creating and executing a stored procedure in embedded SQL:

EXEC SQL CREATE PROCEDURE pettycash( 
 IN Amount DECIMAL(10,2) )
BEGIN
 UPDATE account
 SET balance = balance - Amount
 WHERE name = 'bank';

 UPDATE account
 SET balance = balance + Amount
 WHERE name = 'pettycash expense';
END;
EXEC SQL CALL pettycash( 10.72 );

If you want to pass host variable values to a stored procedure or to retrieve the output variables, you prepare and execute a CALL statement. The following code fragment illustrates the use of host variables. Both the USING and INTO clauses are used on the EXECUTE statement.

EXEC SQL BEGIN DECLARE SECTION;
double  hv_expense;
double  hv_balance;
EXEC SQL END DECLARE SECTION;

// Code here
EXEC SQL CREATE PROCEDURE pettycash(
   IN expense  DECIMAL(10,2),
   OUT endbalance DECIMAL(10,2) )
BEGIN
  UPDATE account
  SET balance = balance - expense
  WHERE name = 'bank';
  UPDATE account
  SET balance = balance + expense
  WHERE name = 'pettycash expense';

  SET endbalance = ( SELECT balance FROM account
         WHERE name = 'bank' );
END;

EXEC SQL PREPARE S1 FROM 'CALL pettycash( ?, ? )';
EXEC SQL EXECUTE S1 USING :hv_expense INTO :hv_balance;

For more information, see EXECUTE statement [ESQL], and PREPARE statement [ESQL].

Stored procedures with result sets

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