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;
        }