A trivial example of a database query performed with JDBC : SQL Select Query « Database SQL JDBC « Java

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2. Database SQL JDBC
3. SQL Select Query

A trivial example of a database query performed with JDBC

/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLWarning;
import java.sql.Statement;

/** A trivial example of a database query performed with JDBC. The database 
 * being queried only exists locally on Windows'95; it the MS Access 
 * "Video Database" sample database. Note that you must select this as 
 * "System DSN" under the name "Video.Collection" (On '95 you
 * do this from Settings->Control Panel->32Bit ODBC->System DSN)
 * for this particular configuration of the demo to work.
 * Other than this (see the URL below), the demo would work on
 * any platform (UNIX, MS, Mac, Novell, etc.).
 *
 * We simply get a JDBC connection to the local Database server via ODBC,
 * create a Statement from that, and a ResultSet with its Query set
 * to a selection of three items from a database table, and print the
 * results in a while loop as they come in from the database.
 */
public class JDBCQuery {

  public static void main(String[] av) {
      try {
      System.out.println("Loading Driver (with Class.forName)");
      // Load the jdbc-odbc bridge driver
      Class.forName ("sun.jdbc.odbc.JdbcOdbcDriver");

      // Enable logging
      // DriverManager.setLogStream(System.err);

      System.out.println("Getting Connection");
      Connection conn = DriverManager.getConnection (
        "jdbc:odbc:Companies",
        "ian", "");  // user, passwd

      // Any warnings generated by the connect?
      checkForWarning(conn.getWarnings());

      System.out.println("Creating Statement");
      Statement stmt = conn.createStatement();

      System.out.println("Executing Query");
      ResultSet rs = stmt.executeQuery("SELECT * FROM Companies");

      System.out.println("Retrieving Results");
      int i = 0;
      while (rs.next()) {

        System.out.println("Retrieving Company ID");
        int x = rs.getInt("CustNO");
        System.out.println("Retrieving Name");
        String s = rs.getString("Company");

        System.out.println("ROW " + ++i + ": " +
          x + "; " + s + "; " + ".");

      }

      rs.close();    // All done with that resultset
      stmt.close();  // All done with that statement
      conn.close();  // All done with that DB connection

      } catch (ClassNotFoundException e) {
      System.out.println("Can't load driver " + e);
      } catch (SQLException e) {
      System.out.println("Database access failed " + e);
      }
  }

  // Format and print any warnings from the connection
  private static void checkForWarning(SQLWarning warn) throws SQLException  {

       // If a SQLWarning object was given, display the
       // warning messages.  Note that there could be
       // multiple warnings chained together

       if (warn != null) {
         System.out.println("*** Warning ***\n");
         while (warn != null) {
           System.out.println("SQLState: " +
             warn.getSQLState());
           System.out.println("Message:  " +
             warn.getMessage());
           System.out.println("Vendor:   " +
             warn.getErrorCode());
           System.out.println("");
           warn = warn.getNextWarning();
         }
       }
     }
}


           
       

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