Bug #21596 column aliases ignored in ResultSetMetaData

• Submitted: 11 Aug 2006 19:11
• Modified: 14 Aug 2006 1:35
• Reporter: Peter Brown
• Status: Duplicate
• Category: Connector / J
• Severity: S2 (Serious)
• Version: 5.0.2-beta, 5.0.3
• OS: Windows (Windows XP)
• CPU Architecture: Any

[11 Aug 2006 19:11] Peter Brown

Description:
the result set meta data for a query like 

  SELECT id as value, description as text from foo

returns 'id' and 'description' as the column names instead of 'value' and 'text'

NOTES:
-above bug occurs with version 5.0.3 + mysql Ver 14.12 Distrib 5.0.22, for Win32 (ia32) + Java 1.5.0_07

-works correctly with version 5.0.3 + mysql  Ver 12.22 Distrib 4.0.16, for Win95/Win98 (i32) + Java 1.4.2_02

-works correctly with version 3.0.9 + mysql 4/java 1.4, or mysql 5/java 1.5

How to repeat:
import java.sql.*;

public class JDBCMetaDataTest
{
  public static void main(String[] args)
  {
    try
    {
      Class.forName("com.mysql.jdbc.Driver");
      Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/tester", "usr", "pwd");
      Statement stmt = connection.createStatement();
      ResultSet rs = stmt.executeQuery("select id as value, description as text from foo");
      ResultSetMetaData rsmd = rs.getMetaData();  
      for ( int i = 1; i <= rsmd.getColumnCount(); i++)
      {
        System.out.println(rsmd.getColumnName(i));
      }
    }
    catch (Exception ex)
    {
      System.out.println(ex.toString());
    }
  }
}

C:\path>javac JDBCMetaDataTest.java

C:\path>java -classpath mysql-connector-java-3.0.9-stable-bin.jar;. JDBCMetaDataTest
value
text

C:\path>java -classpath mysql-connector-java-5.0.3-bin.jar;. JDBCMetaDataTest
id
description

[14 Aug 2006 1:35] Mark Matthews

Duplicate of BUG#21379.

This is a change required for JDBC-compliance. RSMD.getColumnName() is required to return the actual column name. Aliases are returned via RSMD.getColumnLabel().

If you want the older non-compliant behavior from Connector/J 3.1, use the "useOldAliasMetadataBehavior" configuration parameter present in the 5.0 nightly builds, and set it to "true".