IBM Cloudscape/Apache Derby 中的备份、恢复和前滚恢复简介

				
   ij>connect 'jdbc:derby:salesdb';
   ij>CALL SYSCS_UTIL.SYSCS_BACKUP_DATABASE('D:/dbbackups/');

				
private void backUpDatabase(Connection conn) throws SQLException
{
    String sqlstmt = "CALL SYSCS_UTIL.SYSCS_BACKUP_DATABASE(?)";
    CallableStatement cs = conn.prepareCall(sqlstmt); 
    cs.setString(1,"D:/dbbackups/");
    cs.execute(); 
    cs.close();
}

				
String dbURL = "jdbc:derby:salesdb;restoreFrom=D:/dbbackups/salesdb";
Connection conn = DriverManager.getConnection(dbURL);

				
String dbURL = "jdbc:derby:salesdb;restoreFrom=D:/dbbackups/saleddb;logDevice=E:/salesdbLog";
Connection conn = DriverManager.getConnection(dbURL);

				
String dbURL = "jdbc:derby:salesdb;createFrom=D:/dbbackups/salesdb;logDevice=E:/salesdbLog";
Connection conn = DriverManager.getConnection(dbURL);

				
public void backupAndEnableLogArchiveMode(Connection conn) throws SQLException
{
    String sqlstmt = "CALL SYSCS_UTIL.SYSCS_BACKUP_DATABASE_AND_ENABLE_LOG_ARCHIVE_MODE(?, ?)";
    CallableStatement cs = conn.prepareCall(sqlstmt); 
    cs.setString(1, "D:/dbbackups/");
    cs.setInt(2, 0);
    cs.execute(); 
    cs.close();
}

				
public void backupAndEnableLogArchiveMode(Connection conn) throws SQLException
{
    String sqlstmt = "CALL SYSCS_UTIL.SYSCS_BACKUP_DATABASE_AND_ENABLE_LOG_ARCHIVE_MODE(?, ?)";
    CallableStatement cs = conn.prepareCall(sqlstmt); 
    cs.setString(1, "D:/dbbackups/");
    cs.setInt(2, 1);
    cs.execute(); 
    cs.close();
}

				
String dbURL = "jdbc:derby:salesdb;rollForwardRecoveryFrom=D:/dbbackups/salesdb";
Connection conn = DriverManager.getConnection(dbURL);

				
public void disableLogArchiveMode(Connection conn) throws SQLException
{
    String sqlstmt = "CALL SYSCS_UTIL.SYSCS_DISABLE_LOG_ARCHIVE_MODE(?)";
    CallableStatement cs = conn.prepareCall(sqlstmt); 
    cs.setInt(1, 1);
    cs.execute(); 
    cs.close();
}

				
private boolean isLogArchiveModeOn(Connection conn) throws SQLException
{
    Statement stmt = conn.createStatement();
    String sqlstmt = 
       "VALUES SYSCS_UTIL.SYSCS_GET_DATABASE_PROPERTY('derby.storage.logArchiveMode')";
    ResultSet rs = stmt.executeQuery(sqlstmt); 
    rs.next();
    boolean logArchiveStatus = rs.getBoolean(1);
    rs.close();
    stmt.close();
    return logArchiveStatus;
}

				
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.CallableStatement;
import java.sql.SQLException;
import java.util.Timer;
import java.util.TimerTask;
import java.util.Calendar;
import java.util.Date;
import java.text.SimpleDateFormat;
/*
 * This class implements a backup scheduler to schedule database backups once a
 * day at a specified time after a day it is started.
 * 
 * Example usage in an application: 
 * BackupScheduler backups = new BackupScheduler("jdbc:derby:salesdb", "D:/backups");
 *
 * backups.start(23) //run database backups at 11PM everyday. 
 *
 * @see java.util.Timer
 * @see java.util.TimerTask
 */
public class BackupScheduler extends TimerTask 
{
	private final static long BACKUP_INTERVAL = 1000*60*60*24; //once a day
	private String dbURL;
	private String backupPath;
	private Timer timer;
	/* Constructor for Backup Scheduler
	 * @parm dbURL  connection URL that should be used to connect to the database.
	 * @param backUpPath Location where the backup should be placed.
	 */
	public BackupScheduler(String dbURL, String backupPath)	{
		this.dbURL = dbURL;
		this.backupPath = backupPath;
	}
	/**
	 * start the backup scheduler.
	 * @param backupTime the time of the date at which to start the backup
	 *              in  24-hour clock notation.(eg: 1PM 13))
	 */
	public void start(int backupTime)
	{
		timer = new Timer();
		//schedule a backup task everyday at the specified time, starting tomorrow. 
		timer.scheduleAtFixedRate(this,
                                          getTomorrowTime(backupTime),
                                          BACKUP_INTERVAL);
	}
	/**
	 * Implements TimerTask's run method to perform backups. 
	 */
	public void run(){
		try{
			new org.apache.derby.jdbc.EmbeddedDriver();
			Connection conn = DriverManager.getConnection(dbURL);
			backupDatabase(conn);
			conn.close();
		}catch(Exception ex)
		{
			System.out.println("backup failed on:" + dbURL);
			ex.printStackTrace();
		}
	}
	
	/**
         * Performs back up of the database
	 * @param conn  Connnection to the database that is to be backed up.
	 */
	private void backupDatabase(Connection conn) throws SQLException
	{
		SimpleDateFormat dateFormat = new SimpleDateFormat("MM.dd.yy");
		String backupDirectory = backupPath + "/" + dateFormat.format(new Date());
                String sqlstmt = "CALL SYSCS_UTIL.SYSCS_BACKUP_DATABASE(?)";
		CallableStatement cs = conn.prepareCall(sqlstmt); 
		cs.setString(1, backupDirectory);
		cs.execute(); 
		cs.close();
	}
        /**
         * Gets the tomorrows Calenders time at the speficied hour.  
         * @param hourOfDay hour the time to be calculated.
         * @return returns tomorrow time.
         */
	private  Date getTomorrowTime(int hourOfDay){
		Calendar tomorrow = Calendar.getInstance();
		tomorrow.roll(Calendar.DATE, true);
		tomorrow.set(Calendar.HOUR_OF_DAY, hourOfDay);
		tomorrow.set(Calendar.MINUTE, 0);
		tomorrow.set(Calendar.SECOND , 0);
		tomorrow.set(Calendar.MILLISECOND, 0);
		return tomorrow.getTime();
	}
}