Restrict topic delete if it has associated articles

In this page you will add an additional check before a topic is deleted. The check is designed to prevent a topic from being deleted if it has sub-topics underneath it.

1. Open the page containing the NeXTensio Form, detail_art, and add the Check Detail Records behavior from the Server Behaviors menu:
   
   
    

2. When the Check Detail Records interface opens, configure the fields as follows:
   · Detail table: page_pag
   · Foreign Key: idpag_pag (self foreign key)
   · Error Message: type a meaningful error message in the text area.
   
   
    

3. Click the OK button. The server behavior will then be added to the page. Save the page and upload it to the server. You can test the page by logging in to the site, and going to the list_art page in the admin section. Try to delete a record, like IT Conferences, which contains sub-articles:
   
   
   
   After clicking delete an error message (the one you defined) should appear on the detail_art page:
   
   
    

With the Check Detail Records behavior, the only way to delete both an article and it's sub-articles is to individually delete the sub-articles first, then delete the main article. If you decide this is too much of an inconvenience, you can delete the Check Detail Records behavior, and add Delete Detail Records one instead. It is configured in the same way, except without an error message field.
In the next chapter, you will improve your Content Management System by adding advanced features, including auto-archiving old articles, creating rich-text content using the KTML, and search engine optimization.