MySQL Stored procedure, INOUT parameter question.

Question

Hello, I'm trying to run a stored procedure in MySQL 5.0 through the use of Java. Here's what I have:
Part of my Java code (which is taken from the MySQL Connector/J documentation):
    CallableStatement cStmt = conn.prepareCall("{call demoSp(?, ?)}");                                   
    cStmt.registerOutParameter("inOutParam", Types.INTEGER);
    cStmt.setString(1, "hello");
    cStmt.setInt("inOutParam", 4);
    cStmt.execute();
    System.out.println(cStmt.getInt("inOutParam"));The stored procedure (which has been taken directly from the MySQL Connector/J documentation, PDF format, Page 4)
CREATE PROCEDURE demoSp(IN inputParam VARCHAR(255), INOUT inOutParam INT)
BEGIN
    DECLARE z INT;
    SET z = inOutParam + 1;
    SET inOutParam = z;
    SELECT inputParam;
    SELECT CONCAT('zyxw', inputParam);
ENDI have tested the query in MySQL and the stored procedure does work correctly. The Java code successfuly runs the stored procedure, but the INOUT parameter always returns as 1. This behaviour indicates that when the stored procedure runs, inOutParam is set to 0, regardless of what value it is given in the Java code. Therefore, is the INOUT parameter fully supported? Maybe my Java code is incorrect?
Thanks in advance for a response.

Answer 1

I don't see anything obviously wrong with the code. That you are always getting 1 out, suggests the possibility that the input value isn't going in, is defaulting to 0 and 0+ 1 is being returned...
As a guess, try doing:
cStmt.setInt(2, 4);instead of:
cStmt.setInt("inOutParam", 4);It could be that MySQL has some problems with "by name" parameters...
Alternately, modify the stored procedure to put inOutParam into a table and see what value is being recieved...