updatingdemo.java

此程序都是企业级 的数据库开发程序 全面揭示了JAVA对数据库的操作

package results;

import java.sql.*;
import java.io.*;
import connections.*;

public class UpdatingDemo {
  public static void main(String[] args) {
    Connection conn = null;
    Statement stmt = null;
    ResultSet rset = null;

    try {
      conn = ConnectionFactory.getConnection();
      stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, 
                                  ResultSet.CONCUR_UPDATABLE);
      String sql = "SELECT recordingid, tracknumber, tracktitle " 
                   + "FROM tracks ORDER BY recordingid, tracknumber";
      rset = stmt.executeQuery(sql);

      // if (rset.next()) {
      // rset.beforeFirst();
      boolean done = false;
      BufferedReader inr = 
        new BufferedReader(new InputStreamReader(System.in));
      while (!done) {
        System.out.print("\nType F (first), N (next), P (previous), " 
                         + "L (last), Q (quit), I (insert), U (update) : ");
        String s = inr.readLine();
        boolean result = false;
        if (s.equalsIgnoreCase("F")) {
          result = rset.first();
        } else if (s.equalsIgnoreCase("N")) {
          result = rset.next();
        } else if (s.equalsIgnoreCase("P")) {
          result = rset.previous();
        } else if (s.equalsIgnoreCase("L")) {
          result = rset.last();
        } else if (s.equalsIgnoreCase("Q")) {
          done = true;
        } else if (s.equalsIgnoreCase("U")) {
          updateRow(rset, inr, false);
        } else if (s.equalsIgnoreCase("I")) {
          rset.moveToInsertRow();
          updateRow(rset, inr, true);
        } 
        if (done) {
          break;
        } 
        if (result) {
          System.out.println("cursor moved to row " + rset.getRow());
          System.out.println("Record Id : " + rset.getInt(1) 
                             + ", Track Number : " + rset.getInt(2) 
                             + ", Track Title : " + rset.getString(3));
        } else {
          if (!s.equalsIgnoreCase("U") &&!s.equalsIgnoreCase("I")) {
            System.out.println("Could not move cursor");
          } 
        } 
      } 
      inr.close();

      // } else {
      // System.out.println("ResultSet contained no rows");
      // }
    } catch (Exception e) {
      e.printStackTrace();
    } 
    finally {
      ConnectionFactory.close(rset);
      ConnectionFactory.close(stmt);
      ConnectionFactory.close(conn);
    } 
  } 

  public static void updateRow(ResultSet rset, BufferedReader inr, 
                               boolean insert) throws SQLException, 
                               IOException {
    System.out.print("Enter Recording Id: ");
    String recordId = inr.readLine();
    rset.updateInt("RECORDINGID", Integer.parseInt(recordId));

    System.out.print("Enter Track Number: ");
    String trackNumber = inr.readLine();
    rset.updateInt("TRACKNUMBER", Integer.parseInt(trackNumber));

    System.out.print("Enter Track Title: ");
    String trackTitle = inr.readLine();
    rset.updateString("TRACKTITLE", trackTitle);

    System.out.print("Enter Y to commit the change, " 
                     + "or any other key to stop the update: ");
    String choice = inr.readLine();
    if (choice.equalsIgnoreCase("Y")) {
      if (insert) {
        rset.insertRow();
        rset.moveToCurrentRow();
      } else {
        rset.updateRow();
      } 
    } 
  } 
}