sqlDataApter与sqlcommand的关系

  其实 数据库的连接是隐式的被打开的

SqlDataAdapter  sqlDateAdapter = new SqlDataAdapter(sql语句,connection);

其实它是隐式的替代了下面的代码:

conn.Open();

                SqlCommand cmd = new SqlCommand();

                cmd.CommandText = "select * from googs";

                cmd.CommandType = CommandType.Text;

                cmd.Connection = conn;

                SqlDataAdapter   sqlDateAdapter = new SqlDataAdapter();

                sqlDateAdapter.SelectCommand = cmd;

现在看出原因了吧！！