JDBC GS updating ResultSet rows.

Updating data in a ResultSet table using a Statement object.

1. First you need to Create a Database Connection.
2. For this purpose, you must create an updatable ResultSet object as previously described.
3. Now you can set the cursor to a row using one of the positioning methods in the ResultSet object. Which methods of these to use depends on the scrolling you have selected when you created the Statement object.
4. When a row in the ResultSet is accessible several ResultSet methods can be used to update column data.
   Here is the most used:

   Methods in ResultSet interface	Description
   void updateDouble(int, double) void updateDouble(String, double)	Updates a double in the column with number (1.. N) or database table defined column name.
   void updateFloat(int, float) void updateFloat(String, float)	Updates a float in the column with number (1.. N) or database table defined column name.
   void updateInt(int, int) void updateInt(String, int)	Updates an int in the column with number (1.. N) or database table defined column name.
   void updateLong(int, long) void updateLong(String, long)	Updates a long in the column with number (1.. N) or database table defined column name.
   void updateShort(int, short) void updateShort(String, short)	Updates a short in the column with number (1.. N) or database table defined column name.
   void updateString(int, String) void updateString(String, String)	Updates a String in the column with number (1.. N) or database table defined column name.
   void updateTime(int, Time) void updateTime(String, Time)	Updates a Time in the column with number (1.. N) or database table defined column name.
   void updateDate(int, Date) void updateDate(String, Date)	Updates a Date in the column with number (1.. N) or database table defined column name.
   void updateTimestamp(int, Timestamp) void updateTimestamp(String, Timestamp)	Updates a Timestamp in the column with number (1.. N) or database table defined column name.
   void updateBoolean(int, boolean) void updateBoolean(String, boolean)	Updates a boolean in the column with number (1.. N) or database table defined column name.
   void updateByte(int, byte) void updateByte(String, byte)	Updates a byte in the column with number (1.. N) or database table defined column name.
   void updateBytes(int, byte[]) void updateBytes(String, byte[])	Updates a array of byte in the column with number (1.. N) or database table defined column name.
   void updateArray(int, Array) void updateArray(String, Array)	Updates a Array of objects in the column with number (1.. N) or database table defined column name.
   void updateBigDecimal(int, BigDecimal) void updateBigDecimal(String, BigDecimal)	Updates a BigDecimal in the column with number (1.. N) or database table defined column name.
   void updateObject(int, Object) void updateObject(String, Object)	Updates a Object in the column with number (1.. N) or database table defined column name.
   void updateObject(int, Object, int) void updateObject(String, Object, int)	Updates a Object in the column with number (1.. N) or database table defined column name. The last parameter is for a BigDecimal , the number of digits after the decimal point an for Java Object types InputStream and Reader, this is the length of the data in the stream or reader.
   void updateRowId(int, RowId) void updateRowId(String, RowId)	Updates a RowId in the column with number (1.. N) or database table defined column name.
   void updateBinaryStream(int, InputStream) void updateBinaryStream(String, InputStream)	Updates a InputStream of bytes in the column with number (1.. N) or database table defined column name.
   void updateCharacterStream(int, Reader) void updateCharacterStream(String, Reader)	Updates a Reader containing the column value using the column number (1.. N) or database table defined column name.

5. When you have updated the columns as required, (depending on the Database table Column definition) you must use the updateRow() method to update the database table. This method cannot be called when the cursor is on an insert type of row.
6. If you may decide that you don’t want to update the row, you can call the void cancelRowUpdates() method instead.
   Example of updating data in a ResultSet table using a Statement object:

   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 UpdateResultSet {
   
     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 for a ResultSet access that is
         // sensitive for other users updating of tables in the database and
         // the ResultSet is updatable for selected table in the database.
         stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                 ResultSet.CONCUR_UPDATABLE);
         // Create a  ResultSet with a query that returns
         // the data from the dB table Carpark
         ResultSet resultSet = stmt.executeQuery("select * from Carpark ");
         // As cursor was placed before first row after the resultSet was opened
         // we use the next() method to
         // test and read the first row in the ResultSet.
         if (resultSet.next()) {
           // using a loop to retrieve rows and column data to create a
           // html coded table output
           System.out.println("<table border='1'>");
           do {
             System.out.println("<tr >");
             System.out.print("<td>" + resultSet.getString("regNo") + "</td>");
             System.out.print("<td>" + resultSet.getString("cartype") + "</td>");
             System.out.println("<td>" + resultSet.getInt("model") + "</td>");
             System.out.println("<td>" + resultSet.getDouble("dayPrice") + "</td>");
             // Calculate a new day price for each car and update 
             // the database table CarPark
             resultSet.updateDouble("NewPrice",resultSet.getDouble("dayPrice")*0.8);
             resultSet.updateRow();
             // prints the new price
             System.out.println("<td>" + resultSet.getDouble("NewPrice") + "</td>");
             System.out.println("</tr>");
           } while (resultSet.next());
           System.out.println("</table>");
         }
       } catch (ClassNotFoundException ex) {
         Logger.getLogger(UpdateResultSet.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 > <td>AD23443</td><td>BMW</td><td>2001</td> <td>300.0</td> <td>240.0</td> </tr> <tr > <td>AX72345</td><td>AUDI</td><td>2003</td> <td>350.0</td> <td>280.0</td> </tr> <tr > <td>CE23473</td><td>AUDI</td><td>2001</td> <td>400.0</td> <td>320.0</td> </tr> <tr > <td>DE12345</td><td>AUDI</td><td>2003</td> <td>250.0</td> <td>200.0</td> </tr> <tr > <td>DE23453</td><td>FORD</td><td>2002</td> <td>375.0</td> <td>300.0</td> </tr> <tr > <td>DE34562</td><td>OPEL</td><td>2001</td> <td>340.0</td> <td>272.0</td> </tr> <tr > <td>RE23456</td><td>FORD</td><td>2005</td> <td>350.0</td> <td>280.0</td> </tr> </table>

   AD23443 BMW 2001 300.0 240.0 AX72345 AUDI 2003 350.0 280.0 CE23473 AUDI 2001 400.0 320.0 DE12345 AUDI 2003 250.0 200.0 DE23453 FORD 2002 375.0 300.0 DE34562 OPEL 2001 340.0 272.0 RE23456 FORD 2005 350.0 280.0