如何删除子类别并显示成功消息

Question

I want to delete a sub category and display a message about the deletion upon success. However, my query does not delete anything. How can I fix it?

table structure:

Software 
CategoryID=100, SubCategoryID=NULL (main category)
Asp.Net
CategoryID=100, SubCategoryID=100 (sub category)`

code

if (Process == "Delete")
{
    system.cmd("DELETE FROM TBLCATEGORIES where SubCategoryID =" + CategoryID);
    DeleteMsg.Visible = true;
}

Delete Message

      <div class="alert alert-info"  id="DeleteMsg" runat="server"  visible="false">

Answer 1

You have an error in your SQL query. You should write:

     system.cmd("DELETE FROM TBLCATEGORIES where SubCategoryID = " + CategoryID);

In addition you should use parameters in your SQL queries. It's more efficient and prevent from SQL injection attacks ( Adding parameter to command ).

Answer 2

Instead of writing the query directly in code; first check the queries in Sql server management studio, because your query is not correct, I believe you want to delete all the sub categories below a specific category, if that is the case then you will match the category column and that is it.

Hope this helps