SQL技能天天练（2）数据备份与还原

有两种方法，都是保存为.bak文件。一种是直接用Sql语句执行，另一种是通过引用SQL Server的SQLDMO组件来实现:

 1.通过执行Sql语句来实现

注意，用Sql语句实现备份与还原操作时，最好不要使用需要备份或还原的数据库连接，而使用master，否则可能会出现如下三个问题：(1)超时时间已到。在操作完成之前超时时间已过或服务器未响应。(2)  在向服务器发送请求时发生传输级错误。(provider:共享内存提供程序,error:0-系统无法打开文件。)  (3)从服务器接收结果时发生传输级错误。(provider:共享内存提供程序，error:0   -   系统无法打开文件。) ，如果一定要用这个连接的话，要注意在执行Sql语句前加个Sql语句：use master，这样可能会解决以上问题。

 

     (1)数据备份语句：backup database  数据库名 to disk='保存路径/dbName.bak'

     (2)数据恢复语句：restore database 数据库名 from disk='保存路径/dbName.bak'   WITH MOVE 'dbName_Data' TO 'c:/tcomcrm20041217.mdf', --数据文件还原后存放的新位置
MOVE 'dbName_Log' TO 'c:/comcrm20041217.ldf' ----日志文件还原后存放的新位置

关于这两个语句还有更详细的介绍：http://blog.csdn.net/holyrong/archive/2007/08/29/1764105.aspx

            //数据库备份与恢复实例

            private void btnBak_Click(object sender, EventArgs e) //备份
        {
            string saveAway = this.tbxBakLoad.Text.ToString().Trim();
            string cmdText = @"backup database " + System.Configuration.ConfigurationSettings.AppSettings["dbName"] + " to disk='" + saveAway + "'";
            BakReductSql(cmdText,true);            
        }

 

        private void btnReduct_Click(object sender, EventArgs e)  //恢复
        {
            string openAway = this.tbxReductLoad.Text.ToString().Trim();//读取文件的路径
            string cmdText = @"restore database " + System.Configuration.ConfigurationSettings.AppSettings["dbName"] + " from disk='" + openAway + "'";            
            BakReductSql(cmdText,false);
        }

 

        /// <summary>
        /// 对数据库的备份和恢复操作，Sql语句实现
        /// </summary>
        /// <param name="cmdText">实现备份或恢复的Sql语句</param>
        /// <param name="isBak">该操作是否为备份操作，是为true否，为false</param>
        private void BakReductSql(string cmdText,bool isBak)
        {
            SqlCommand cmdBakRst = new SqlCommand();
            SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=master;uid=sa;pwd=;");

            try
            {
                conn.Open();
                cmdBakRst.Connection = conn;
                cmdBakRst.CommandType = CommandType.Text;
                if (!isBak)     //如果是恢复操作
                {
                    string setOffline = "Alter database GroupMessage Set Offline With rollback immediate ";
                    string setOnline = " Alter database GroupMessage Set Online With Rollback immediate";
                    cmdBakRst.CommandText = setOffline + cmdText + setOnline;
                }
                else
                {
                    cmdBakRst.CommandText = cmdText;
                }
                cmdBakRst.ExecuteNonQuery();
                if (!isBak)
                {
                    MessageBox.Show("恭喜你，数据成功恢复为所选文档的状态！", "系统消息");
                }
                else
                {
                    MessageBox.Show("恭喜，你已经成功备份当前数据！", "系统消息");
                }
            }
            catch (SqlException sexc)
            {
                MessageBox.Show("失败，可能是对数据库操作失败，原因：" + sexc, "数据库错误消息");
            }
            catch (Exception ex)
            {
                MessageBox.Show("对不起，操作失败，可能原因：" + ex, "系统消息");
            }
            finally
            {
                cmdBakRst.Dispose();
                conn.Close();
                conn.Dispose();
            }
        }

 

另外，如果出现：“尚未备份数据库的日志尾部”错误，可以在还原语句后加上 With Replace 或 With stopat

                   

 

2.用SQLDMO实现（下面代码引用别人的）

    //数据库备份
        string backaway =textbox1.Text.Trim();
            SQLDMO.Backup oBackup = new SQLDMO.BackupClass();
            SQLDMO.SQLServer oSQLServer = new SQLDMO.SQLServerClass();
            try
            {
                oSQLServer.LoginSecure = false;
                //下面设置登录sql服务器的ip,登录名,登录密码
                oSQLServer.Connect(serverip, serverid, serverpwd);
                oBackup.Action = 0;
               //下面两句是显示进度条的状态
                SQLDMO.BackupSink_PercentCompleteEventHandler pceh = new SQLDMO.BackupSink_PercentCompleteEventHandler(Step2);
                oBackup.PercentComplete += pceh;
                //数据库名称:
                oBackup.Database = "k2";
                //备份的路径
                oBackup.Files = @backaway;
                //备份的文件名
                oBackup.BackupSetName = "k2";
                oBackup.BackupSetDescription = "数据库备份";
                oBackup.Initialize = true;
                oBackup.SQLBackup(oSQLServer);
                MessageBox.Show("备份成功！", "提示");
            }
            catch
            {
                MessageBox.Show("备份失败！", "提示");
            }
            finally
            {
                oSQLServer.DisConnect();
            }



//数据库恢复
        //获取恢复的路径
        string dbaway = textbox2.Text.Trim();
            SQLDMO.Restore restore = new SQLDMO.RestoreClass();
            SQLDMO.SQLServer server = new SQLDMO.SQLServerClass();
            server.Connect(serverip, serverid, serverpwd);

            //KILL DataBase Process
            conn = new 工资管理系统.CCUtility.connstring();
            conn.DBOpen();
            SqlCommand cmd = new SqlCommand("use master Select spid FROM sysprocesses ,sysdatabases Where sysprocesses.dbid=sysdatabases.dbid AND sysdatabases.Name='k2'", conn.Connection);
            SqlDataReader dr = cmd.ExecuteReader();
            while (dr.Read())
            {
                server.KillProcess(Convert.ToInt32(dr[0].ToString()));
            }
            dr.Close();
            conn.DBClose();

            try
            {
                restore.Action = 0;
                SQLDMO.RestoreSink_PercentCompleteEventHandler pceh = new SQLDMO.RestoreSink_PercentCompleteEventHandler(Step); 
                restore.PercentComplete += pceh;
                restore.Database = "k2";
                restore.Files = @dbaway;
                restore.ReplaceDatabase = true;
                restore.SQLRestore(server);
                MessageBox.Show("数据库恢复成功！");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                server.DisConnect();
            }

恢复相关的参数和备份相同,不再解释,自己看一下.

上面两个函数调用到了更改进度条的两个函数:

       private void Step2(string message, int percent)
        {
            progressBar2.Value = percent;
        }

        private void Step(string message, int percent)
        {
            progressBar1.Value = percent;
        }

setp对应备份,,setp2对应恢复....