JDBC GS DDL statements with execute

How to do SQL DDL Statements with the execute() method existing in the Statement Object?

  1. First you need to Create a Database Connection.
  2. Then create a regular Statement object with the method, createStatement().
  3. The next step is to write your SQL DDL statement and give this string as a parameter to the method:
    Method in Statement interface Description
    boolean execute(String sql) Executes the given SQL statement, and returns true if the first result is a ResultSet object; false if it is an update count or there are no results.
    Example of using this method to use SQL DDL statement:
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.logging.Level;
    import java.util.logging.Logger;
    
    public class SQLAlter {
    
     public static void main(String[] args) {
      Connection conn = null;
      Statement stmt = null;
      try {
       // Register a driver for the MySQL database
       Class.forName("com.mysql.jdbc.Driver");
       // Create a url for accessing the MySQL
       // database CarDB
       String url = "jdbc:mysql://localhost:3306/CarDB";
       // user and password to access the database
       String username = "root";
       String password = "root";
       // User the DriverManager to get a Connection to the database
       conn = DriverManager.getConnection(url, username, password);
       // Create a  Statement
       // that is non-updateable, non-scrollable conserning ResultSet
       stmt = conn.createStatement();
       // Create an SQL DDL Statement to add a Column, TotalCost,
       // to the CARRENTAL Table
       String alterQuery = "ALTER TABLE CARRENTAL " +
                           "ADD COLUMN TotalCost numeric";
       boolean result = stmt.execute(alterQuery);
       // Update the new Column, TotalCost,
       // to be the cost for each rental of the cars.
       String query = "Update CARRENTAL r set TotalCost=RENTALDAYS*" +
               "(Select c.dayPrice from CARPARK c where c.RegNO=r.RegNO) ";
       result = stmt.execute(query);
       // Create a  ResultSet with a query that returns
       // all the columns  from the dB table Carpark
       // using the execute() method.
       result = stmt.execute("select * from Carpark c, " +
               "CARRENTAL r where c.REGNO=r.REGNO ");
       ResultSet resultSet = null;
       // if result true it is a ResultSet
       if (result) {
        resultSet = stmt.getResultSet();
       }
       // As cursor is at the before first row position
       // we use the next() method to
       // test and read the first row in the ResultSet.
       if (resultSet.next()) {
        // Then we use a loop to retrieve rows and column data
        // and creates a html coded table output
        System.out.println("<table border='1' >");
        System.out.println("<tr>");
        System.out.print("<th>regNo</th>");
        System.out.println("<th>cartype</th>");
        System.out.println("<th>model</th>");
        System.out.println("<th>day<br/>Price</th>");
        System.out.println("<th>Cost</th>");
        System.out.println("</tr>");
        do {
         System.out.println("<tr>");
         System.out.print("<td>" + resultSet.getString("regNo") + "</td>");
         System.out.println("<td>" + resultSet.getString("cartype") + "</td>");
         System.out.println("<td>" + resultSet.getInt("model") + "</td>");
         System.out.println("<td>" + resultSet.getDouble("dayPrice") + "</td>");
         System.out.println("<td>" + resultSet.getDouble("TotalCost") + "</td>");
         System.out.println("</tr>");
        } while (resultSet.next());
        System.out.println("</table>");
       }
      } catch (ClassNotFoundException ex) {
       Logger.getLogger(SQLAlter.class.getName()).log(Level.SEVERE, null, ex);
      } catch (SQLException e) {
       e.printStackTrace();
      } finally {
       try {
        // Close the Statement, which also close the ResultSet
        stmt.close();
        conn.close();
       } catch (Exception xe) {
        xe.printStackTrace();
       }
      }
     }
    }

    You should use the close() method in the Statement object when you do not need it anymore.

    You should also use the close() method in the Connection object when you do not need it anymore.

    You can download this example here (needed tools can be found in the right menu on this page).

    If we run this application the result should be:
    As pure output Translated by a Browser
    <table border='1' >
    <tr>
    <th>regNo</th><th>cartype</th>
    <th>model</th>
    <th>day<br/>Price</th>
    <th>Cost</th>
    </tr>
    <tr>
    <td>DE12345</td><td>AUDI</td>
    <td>2003</td>
    <td>250.0</td>
    <td>1250.0</td>
    </tr>
    <tr>
    <td>DE12345</td><td>AUDI</td>
    <td>2003</td>
    <td>250.0</td>
    <td>750.0</td>
    </tr>
    <tr>
    <td>RE23456</td><td>FORD</td>
    <td>2005</td>
    <td>350.0</td>
    <td>2450.0</td>
    </tr>
    <tr>
    <td>RE23456</td><td>FORD</td>
    <td>2005</td>
    <td>350.0</td>
    <td>1750.0</td>
    </tr>
    <tr>
    <td>CE23473</td><td>AUDI</td>
    <td>2001</td>
    <td>400.0</td>
    <td>1600.0</td>
    </tr>
    <tr>
    <td>DE34562</td><td>OPEL</td>
    <td>2001</td>
    <td>340.0</td>
    <td>1020.0</td>
    </tr>
    <tr>
    <td>DE34562</td><td>OPEL</td>
    <td>2001</td>
    <td>340.0</td>
    <td>1700.0</td>
    </tr>
    </table>
    
    regNocartypemodel day
    Price
    Cost
    DE12345AUDI2003 250.0 1250.0
    DE12345AUDI2003 250.0 750.0
    RE23456FORD2005 350.0 2450.0
    RE23456FORD2005 350.0 1750.0
    CE23473AUDI2001 400.0 1600.0
    DE34562OPEL2001 340.0 1020.0
    DE34562OPEL2001 340.0 1700.0

© 2010 by Finnesand Data. All rights reserved.
This site aims to provide FREE programming training and technics.
Finnesand Data as site owner gives no warranty for the correctness in the pages or source codes.
The risk of using this web-site pages or any program codes from this website is entirely at the individual user.