如果存在 [英] IF Exists

问题描述

大家好，

我有一个插入名字的程序，但是它必须检查表中是否存在该名称，如果存在，它应该返回一条消息，提示已经存在了.

存在，如果不存在，则插入应该继续.


这些是我的代码:


我的存储过程读取:

Hi all,

I have a stroed procedure to insertname, but it has to check if the name exists in the table, if it exist it should return a message that it already

exist, if it doesnt exist insertion should go on.


These are my codes:


My Stored procedure reads:

ALTER procedure dbo.InsertName

@Cname nchar(10),
@Address nchar(10),
@ret varchar(100) output
as

if exists (select * from mytable where Cname=@Cname)

begin

select @ret as [ret]

set @ret='insert failed. Record exists already'

end

else

begin

insert into mytable values (@Cname,@Address)

select @ret as [ret]

set @ret='insert successful'

end

我的代码在这里:

My Code behind here:

protected void Button1_Click(object sender, EventArgs e)
    	{

        string constr = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\Database.mdf;Integrated Security=True;User Instance=True";
        string result="";
        SqlConnection conn = new SqlConnection(constr);
        SqlCommand cmd = new SqlCommand();
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.CommandText = "InsertName";
        cmd.Parameters.AddWithValue("@Cname", this.TextBox1.Text);
        cmd.Parameters.AddWithValue("@Address", this.TextBox2.Text);
        cmd.Parameters.AddWithValue("@ret", result);
        cmd.Connection = conn;
        cmd.Parameters["@ret"].Direction = ParameterDirection.InputOutput;
        
        conn.Open();
        cmd.ExecuteNonQuery();
        Label1.Text = result;

	}

它可以工作，但是它不会在标签控件上显示该消息，请告诉我我做错了什么.

谢谢

---

.Neter

It works, but it doesn't display the message on the label control, please tell me what I have done wrong.

Thanks

---

.Neter

推荐答案

.Neter，您好，

我首先想告诉您，对于存储过程，您应该在某个sql论坛上启动线程.然后，我看到了您的C#代码.肯定在VB通用论坛中，这两个地方都是问这个问题的错误位置.

Hi .Neter,

i first wanted to tell you, that for stored procedures you should start a thread at some sql forum. Then i have seen your C# Code. Both in a VB General forum is for sure the wrong place to ask this question.

这篇关于如果存在的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！