SqlServer的那些常用操作(一)

一、判断数据库的连接状态:
(1)Using方法:
public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        using (SqlConnection connection = new SqlConnection(""))
        {
            connection.Open();
            if (connection.State == ConnectionState.Open)
            {
                //已经打开
            }
        }
    }
}



(2)“Try{}  Catch{}”方法
try
{
SqlConnection conn = new SqlConnection("Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;");
  conn.Open();
}
catch
{
//连接失败
}


(3)永远返回正确的数据连接

  private SqlConnection connection;
  public SqlConnection Connection
  {
  get
  {
  string connectionString = "server=.;database=DB;uid=SA;pwd=123456";
  if (connection == null)
  {
  connection = new SqlConnection(connectionString);
  connection.Open();//这里就是打开了,说明连接上了
  }
  else if (connection.State == System.Data.ConnectionState.Closed)
  {
  connection.Open(); //这里就是打开了,说明连接上了
  }
  else if (connection.State == System.Data.ConnectionState.Broken)
  {
  connection.Close();
  connection.Open();//这里就是打开了,说明连接上了
  }
  return connection; //不管什么情况,这里总是返回一个打开的连接
  }
  }



二、返回本地计算机的所有数据库名称
USE master
SELECT dbid, DB_NAME(dbid) AS DB_NAME
FROM sysdatabases
ORDER BY dbid
GO



三、返回指定数据库中所有的表名称
SELECT name FROM sys.sysobjects WHERE type='U'



四、返回指定表中的所有字段
SELECT *  FROM syscolumns  WHERE id in( SELECT id  FROM sysobjects   WHERE (name = '" + tbname + "'))

posted on 2011-10-28 16:41  [CC]  阅读(219)  评论(0编辑  收藏  举报

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