JDBC for MySQL - Herong's Tutorial Examples - v3.12, by Herong Yang
Common Errors with CallableStatement Parameters
This section provides some error conditions on CallableStatement place holder parameters.
While testing CallableStatement objects with place holder parameters, I noticed two common errors as shown in this program:
/* MySqlCallParameterError.java * Copyright (c) HerongYang.com. All Rights Reserved. */ import java.sql.*; public class MySqlCallParameterError { public static void main(String [] args) { Connection con = null; try { com.mysql.cj.jdbc.MysqlDataSource ds = new com.mysql.cj.jdbc.MysqlDataSource(); ds.setServerName("localhost"); ds.setPortNumber(3306); ds.setDatabaseName("HerongDB"); ds.setUser("Herong"); ds.setPassword("TopSecret"); con = ds.getConnection(); // Create CallableStatement CallableStatement cs = con.prepareCall( "CALL ReverseProcedure(?,?,?)"); // Provide values for IN parameters // Error 2 - Forget to provide values for IN parameters String word = "Herong"; cs.setString(1,word); // Register OUT parameters // Error 1 - Can not register OUT parameters cs.registerOutParameter(1, java.sql.Types.VARCHAR); cs.registerOutParameter(2, java.sql.Types.VARCHAR); cs.registerOutParameter(3, java.sql.Types.INTEGER); // Execute the CALL statement and ignore result sets cs.executeUpdate(); // Retrieve values from OUT parameters String reversed = cs.getString(2); int length = cs.getInt(3); System.out.println("Input word: "+word); System.out.println("Output word: "+reversed); System.out.println("Word length: "+length); // Close resource cs.close(); con.close(); } catch (Exception e) { System.err.println("Exception: "+e.getMessage()); e.printStackTrace(); } } }
Compile and run this program as is, you will get this error message at line 28, because registering an IN parameter as statement output parameter is not allowed:
herong> java -cp .:mysql-connector-java.jar \ MySqlCallParameterError.java java.sql.SQLException: Parameter number 1 is not an OUT parameter at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(...) at com.mysql.cj.jdbc.CallableStatement.checkIsOutputParam(...) at com.mysql.cj.jdbc.CallableStatement.registerOutParameter(...) at MySqlCallParameterError.main(MySqlCallParameterError.java:29)
Table of Contents
JDBC (Java Database Connectivity) Introduction
MySQL JDBC Driver (MySQL Connector/J)
MySQL - Reference Implementation of JdbcRowSet
►MySQL - JBDC CallableStatement
Overview of CallableStatement Objects
"CREATE PROCEDURE" - Creating a Simple Procedure
Creating Procedures with IN and OUT Parameters
Creating Procedures with INOUT Parameters
Creating Procedures with Multiple Queries
Creating CallableStatement Objects with prepareCall()
Capturing ResultSet with executeQuery()
Creating CallableStatement Objects with Parameters
►Common Errors with CallableStatement Parameters
Creating CallableStatement Objects with INOUT Parameters
Retrieving Multiple ResultSet Objects
Executing Stored Procedures without Permission
getProcedures() - Listing Stored Procedures
MySQL CLOB (Character Large Object) - TEXT
MySQL BLOB (Binary Large Object) - BLOB