1         public void InsertDataToSQL()
 2         {
 3             string conStr = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
 4             SqlConnection conn = new SqlConnection(conStr);
 5             conn.Open();
 6 
 7             SqlCommand cmd = new SqlCommand();
 8             cmd.Connection = conn;
 9             cmd.CommandText = "INSERT INTO CUSTOMERS(CustomerID,CompanyName,ContactName) Value(‘bille‘,‘XYZ COMMPANY‘,‘Bill Evjen‘)";
10 
11             //插入操作是通过  cmd.ExecuteNonQuery(); 方法实现的
12             cmd.ExecuteNonQuery();
13             conn.Close();
14         }

 1         public int UpdateDataToSQL()
 2         {
 3             string conStr = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
 4             SqlConnection conn = new SqlConnection(conStr);
 5             conn.Open();
 6 
 7             SqlCommand cmd = new SqlCommand();
 8             cmd.Connection = conn;
 9             cmd.CommandText = "UPDATE Employees SET emp_bonus =1000 WHERE yrs_duty >=5";
10 
11             //cmd.ExecuteNonQuery() 返回更新受影响的记录数
12             int RecordsAffected = cmd.ExecuteNonQuery();
13             return RecordsAffected;
14         }

 1         public int DeleteEmployee()
 2         {
 3             string conStr = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
 4             SqlConnection conn = new SqlConnection(conStr);
 5             conn.Open();
 6 
 7             SqlCommand cmd = new SqlCommand();
 8             cmd.Connection = conn;
 9             cmd.CommandText = "DELETE Employees WHERE LastName = ‘Evjen‘";
10                
11             //返回删除的记录数
12             int RecordsAffected = cmd.ExecuteNonQuery();
13             return RecordsAffected;
14         }