存储过程从入门到熟练(c#篇)

①为什么要使用存储过程?
因为它比SQL语句执行快.

②存储过程是什么?
把一堆SQL语句罗在一起,还可以根据条件执行不通SQL语句.(AX写作本文时观点)

③来一个最简单的存储过程
CREATE PROCEDURE dbo.testProcedure_AX
AS
select userID from USERS order by userid desc

注:dbo.testProcedure_AX是你创建的存储过程名,可以改为:AXzhz等,别跟关键字冲突就行了.AS下面就是一条SQL语句,不会写SQL语句的请回避.

④我怎么在ASP.NET中调用这个存储过程?
下面黄底的这两行就够使了.
        public static string GetCustomerCName(ref ArrayList arrayCName,ref ArrayList arrayID)
        {
            SqlConnection con=ADConnection.createConnection();
            SqlCommand cmd=new SqlCommand("testProcedure_AX",con);
            cmd.CommandType=CommandType.StoredProcedure;
            con.Open();
            try
            {
                SqlDataReader dr=cmd.ExecuteReader();
                while(dr.Read())
                {
                    if(dr[0].ToString()=="")
                    {
                        arrayCName.Add(dr[1].ToString());
                    }
                }
                con.Close();
                return "OK!";
            }
            catch(Exception ex)
            {
                con.Close();
                return ex.ToString();
            }
        }
注:其实就是把以前
SqlCommand cmd=new SqlCommand("select userID from USERS order by userid desc",con);
中的SQL语句替换为存储过程名,再把cmd的类型标注为CommandType.StoredProcedure(存储过程)

⑤写个带参数的存储过程吧,上面这个简单得有点惨不忍睹,不过还是蛮实用的.
参数带就带两,一个的没面子,太小家子气了.

CREATE PROCEDURE dbo.AXzhz
/*
这里写注释
*/
@startDate varchar(16),
@endDate varchar(16)
AS
 select id  from table_AX where commentDateTime>@startDate and commentDateTime<@endDate order by contentownerid DESC

注:@startDate varchar(16)是声明@startDate 这个变量,多个变量名间用【,】隔开.后面的SQL就可以使用这个变量了.

⑥我怎么在ASP.NET中调用这个带参数的存储过程?

 public static string GetCustomerCNameCount(string startDate,string endDate,ref DataSet ds)
{
            SqlConnection con=ADConnection.createConnection();
//-----------------------注意这一段--------------------------------------------------------------------------------------------------------
            SqlDataAdapter da=new SqlDataAdapter("AXzhz",con);

            para0=new SqlParameter("@startDate",startDate);
            para1=new SqlParameter("@endDate",endDate);
            da.SelectCommand.Parameters.Add(para0);
            da.SelectCommand.Parameters.Add(para1);
            da.SelectCommand.CommandType=CommandType.StoredProcedure;
//-------------------------------------------------------------------------------------------------------------------------------

            try
            {
                con.Open();
                da.Fill(ds);
                con.Close();
                return "OK";
            }
            catch(Exception ex)
            {
                return ex.ToString();
            }           
        }

注:把命令的参数添加进去,就OK了
鸟的,改字体颜色的东西太垃圾了,改不好,大家凑活着看.

⑦我还想看看SQL命令执行成功了没有.
注意看下面三行红色的语句

CREATE PROCEDURE dbo.AXzhz
/*
  @parameter1 用户名
  @parameter2 新密码
*/
@password nvarchar(20),
@userName nvarchar(20)
AS
declare @err0 int
update WL_user set password=@password where UserName=@userName
set @err0=@@error
select  @err0 as err0

注:先声明一个整型变量@err0,再给其赋值为@@error(这个是系统自动给出的语句是否执行成功,0为成功,其它为失败),最后通过select把它选择出来,某位高人说可以通过Return返回,超出本人的认知范围,俺暂时不会,以后再补充吧

⑧那怎么从后台获得这个执行成功与否的值呢?
下面这段代码可以告诉你答案:
    public static string GetCustomerCName()
        {
            SqlConnection con=ADConnection.createConnection();
           
            SqlCommand cmd=new SqlCommand("AXzhz",con);
            cmd.CommandType=CommandType.StoredProcedure;
            para0=new SqlParameter("@startDate","2006-9-10");
            para1=new SqlParameter("@endDate","2006-9-20");
            da.SelectCommand.Parameters.Add(para0);
            da.SelectCommand.Parameters.Add(para1);
            con.Open();
            try
            {
               Int32 re=(int32)cmd.ExecuteScalar();
                con.Close();
                if (re==0)
                 return "OK!";
                else
                 return "false";
            }
            catch(Exception ex)
            {
                con.Close();
                return ex.ToString();
            }
        }
注:就是通过SqlCommand的ExecuteScalar()方法取回这个值,这句话是从MSDN上找的,俺认为改成:
     int re=(int)cmd.ExecuteScalar();  99%正确,现在没时间验证,期待您的测试!!!

⑨我要根据传入的参数判断执行哪条SQL语句!!~
下面这个存储过程可以满足我们的要求,竟然是Pascal/VB的写法,Begin----End ,不是{},,,对使用C#的我来说,这个语法有点恶心.........

ALTER PROCEDURE dbo.selectCustomerCNameCount
@customerID int
AS
if @customerID=-1
 begin
 select contentownerid ,userCName,count(*) as countAll from view_usercomment group by contentownerid,userCName order by contentownerid DESC
 end
else
 begin
 select contentownerid ,userCName,count(*) as countAll from view_usercomment where contentownerid=@customerID group by contentownerid,userCName order by contentownerid DESC
 end