Creating CallableStatement Objects with INOUT Parameters

<< MySQL - JBDC CallableStatement

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This section describes how to create CallableStatement objects with INOUT parameters.

MySQL procedures do support INOUT parameters, which should be handled like IN parameters and OUT parameters as shown in the previous tutorial.

In a previous tutorial, I defined a store procedure called, C2F(), with 2 INOUT parameters. The program below shows you to create a CallableStatement object to execute this stored procedure:

/**
 * MySqlCallInoutParameter.java
 * Copyright (c) 2007 by Dr. Herong Yang. All rights reserved.
 */
import java.sql.*;
public class MySqlCallInoutParameter {
  public static void main(String [] args) {
    Connection con = null;
    try {
      com.mysql.jdbc.jdbc2.optional.MysqlDataSource ds 
        = new com.mysql.jdbc.jdbc2.optional.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 C2F(?,?)");

// Register INOUT parameters
      cs.registerOutParameter(1, java.sql.Types.REAL);     
      cs.registerOutParameter(2, java.sql.Types.REAL);     

// Provide values for INOUT parameters
      double celsius = 100.0;
      cs.setDouble(1,celsius);

// Execute the CALL statement and ignore result sets
      cs.executeUpdate();

// Retrieve values from INOUT parameters
      double fahrenheit = cs.getDouble(2);
      System.out.println("First test:");
      System.out.println("  Celsius = "+celsius);
      System.out.println("  Fahrenheit = "+fahrenheit);

// Second test
      celsius = 0.0;
      cs.setDouble(1,celsius);
      cs.executeUpdate();
      fahrenheit = cs.getDouble(2);
      System.out.println("First test:");
      System.out.println("  Celsius = "+celsius);
      System.out.println("  Fahrenheit = "+fahrenheit);

// Close resource
      cs.close();

      con.close();
    } catch (Exception e) {
      System.err.println("Exception: "+e.getMessage());
      e.printStackTrace();
    }
  }
}

The execution gave me one surprise. The second test failed with an error that I don' understand:

C:\>javac -cp .;\local\lib\mysql-connector-java-5.0.7-bin.jar
  MySqlCallInoutParameter.java

C:\>java -cp .;\local\lib\mysql-connector-java-5.0.7-bin.jar 
  MySqlCallInoutParameter

First test:
  Celsius = 100.0
  Fahrenheit = 212.0

Exception: Data truncated for column 'F' at row 1
java.sql.SQLException: Data truncated for column 'F' at row 1
   at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:946)
   at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2985)
   at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
   at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
   at com.mysql.jdbc.Connection.execSQL(Connection.java:3256)
   at com.mysql.jdbc.PreparedStatement.executeInternal(...)
   at com.mysql.jdbc.PreparedStatement.executeUpdate(...)
   ...
   at MySqlCallInoutParameter.main(MySqlCallInoutParameter.java:42)

Sections in This Chapter

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