Ado.Net基础拾遗二：插入，更新，删除数据

插入数据

         public void InsertDataToSQL()
         {
             string conStr = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
             SqlConnection conn = new SqlConnection(conStr);
             conn.Open();

             SqlCommand cmd = new SqlCommand();
             cmd.Connection = conn;
             cmd.CommandText = "INSERT INTO CUSTOMERS(CustomerID,CompanyName,ContactName) Value('bille','XYZ COMMPANY','Bill Evjen')";

             //插入操作是通过  cmd.ExecuteNonQuery(); 方法实现的
             cmd.ExecuteNonQuery();
             conn.Close();
         }

更新数据

         public int UpdateDataToSQL()
         {
             string conStr = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
             SqlConnection conn = new SqlConnection(conStr);
             conn.Open();

             SqlCommand cmd = new SqlCommand();
             cmd.Connection = conn;
             cmd.CommandText = "UPDATE Employees SET emp_bonus =1000 WHERE yrs_duty >=5";

             //cmd.ExecuteNonQuery() 返回更新受影响的记录数
             int RecordsAffected = cmd.ExecuteNonQuery();
             return RecordsAffected;
         }

删除数据

         public int DeleteEmployee()
         {
             string conStr = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
             SqlConnection conn = new SqlConnection(conStr);
             conn.Open();

             SqlCommand cmd = new SqlCommand();
             cmd.Connection = conn;
             cmd.CommandText = "DELETE Employees WHERE LastName = 'Evjen'";

             //返回删除的记录数
             int RecordsAffected = cmd.ExecuteNonQuery();
             return RecordsAffected;
         }