ADO.Net 中 SQLHelper 的寫法

ExecuteScalar() 、ExecuteNonQuery() 、ExecuteReader()

在編程中常用當中有以上三種：

 

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
//引用SQL數據
using System.Data;
using System.Data.SqlClient;
namespace ADO
{
    class SQLHelper
    {
        //連接字符串
        private static string connString = "Server=服務器名;DataBase=數據庫名;Uid=用戶名;Pwd=用戶密碼";  
        /// <summary>
        /// 獲取單一結果
        /// </summary>
        /// <param name="sql_string">SQL語句</param>
        /// <returns>返回單一結果</returns>
        public static object ExecuteScalar的方法名(string sql_string)
        {
            SqlConnection myCon = new SqlConnection(connString);
            SqlCommand myCmd = new SqlCommand(sql_string, myCon);
            myCon.Open();
            string result = myCmd.ExecuteScalar();
            myCon.Close();
            return result;
        }
        /// <summary>
        /// 執行非查詢操作
        /// </summary>
        /// <param name="sql_string">SQL語句</param>
        /// <returns>返回受影響的行</returns>
        public static int ExecuteNonQuery的方法名(string sql_string)
        {
            SqlConnection myCon = new SqlConnection(connString);
            SqlCommand myCmd = new SqlCommand(sql_string, myCon);
            myCon.Open();
            int result = myCmd.ExecuteNonQuery();
            myCon.Close();
            return result;
        }
        /// <summary>
        /// 獲取只讀數據集
         /// <param name="sql_string">SQL語句</param>
        /// <returns>返回只讀取數據集</returns>
        /// </summary>
        public static SqlDataReader ExecuteReader的方法名(string sql_string)
        {
            SqlConnection myCon = new SqlConnection(connString);
            SqlCommand myCmd = new SqlCommand(sql_string, myCon);
            myCon.Open();
            string result = myCmd.ExecuteReader(CommandBehavior.CloseConnection);
            return result;
        }
    }
}

 

 

 在 Program 類中調用 SQLHelper

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.SqlClient;

namespace ADO
{
    class Program
    {
        static void Main(string[] args)
        {
            //string sqlString = "delete  from Student where studentNO='S110601'";
            //int myExcuteNonQuery = SQLHelper.myExecuteNonQuery(sqlString);
            //Console.WriteLine(myExcuteNonQuery);


//下面這個要特別注意：
            string sql = "select * from Student where gender='男'";
            sql += "select * from Student where gender='女'";
            SqlDataReader objRead = SQLHelper.ExecuteReader的方法名(sql);
            while (objRead.Read())
            {
                Console.WriteLine(objRead["StudentNO"].ToString() + " " + objRead["StudentName"].ToString() + " " + objRead["gender"].ToString());
            }
            Console.WriteLine("==========================================");
           if( objRead.NextResult())
           {
               while (objRead.Read())
               {
                   Console.WriteLine(objRead["StudentNO"].ToString() + " " + objRead["StudentName"].ToString() + " " + objRead["gender"].ToString());
               }
           }
            objRead.Close();
        }
    }
}

 

SQLHelper 另一種詳細寫法

 

using System;
using System.Collections.Generic;
using System.Text;
//引用SQL數據
using System.Data;
using System.Data.SqlClient;
namespace ConsoleApplication2
{
    class SQLHelper
    {
        //連接字符串
        private static string connString = "Server=.;DataBase=StudentManageDB;Uid=sa;Pwd=123";
        /// <summary>
        /// ExecuteScalar()
        /// </summary>
        /// <param name="sql_string">SQL語句</param>
        /// <returns>返回單個值的功能</returns>
        public static object ExecuteScalar的方法名(string sql_string)
        {
            using (SqlConnection myCon = new SqlConnection(connString))
            {
                using (SqlCommand myCmd = new SqlCommand(sql_string, myCon))
                {
                    try
                    {
                        myCon.Open();
                        return myCmd.ExecuteScalar();
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }
                    finally
                    {
                        myCon.Close();
                    }
                }
            }
        }
        /// <summary>
        /// ExecuteNonQuery()
        /// </summary>
        /// <param name="sql_string">SQL語句</param>
        /// <returns>返回受影響的行</returns>
        public static int myExecuteNonQuery(string sql_string)
        {
            using (SqlConnection myCon = new SqlConnection(connString))
            {
                using (SqlCommand myCmd = new SqlCommand(sql_string, myCon))
                {
                    try
                    {
                        myCon.Open();
                        return myCmd.ExecuteNonQuery();
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }
                    finally
                    {
                        myCon.Close();
                    }
                }
            }
        }
        /// <summary>
        /// ExecuteReader()
        /// </summary>
        /// <param name="sql_string">SQL語句</param>
        /// <returns>返回讀取數據集</returns>
        public static SqlDataReader ExecuteReader的方法名(string sql_string)
        {
            using (SqlConnection myCon = new SqlConnection(connString))
            {
                using (SqlCommand myCmd = new SqlCommand(sql_string, myCon))
                {
                    try
                    {
                        myCon.Open();
                        return myCmd.ExecuteReader(CommandBehavior.CloseConnection);
                    }
                    catch (Exception ex)
                    {
                        throw ex;
                    }
                    finally
                    {
                        myCon.Close();
                    }
                }
            }
        }
    }
}