# Polymorphic Associations and Validation **URL:** \ **Category:** Rails\ **Created:** [March 31, 2007, 11:50am UTC](https://www.ruby-forum.com/t/polymorphic-associations-and-validation/90716 "2007-03-31T11:50:58Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [March 31, 2007, 11:50am UTC](https://www.ruby-forum.com/t/polymorphic-associations-and-validation/90716/1 "2007-03-31T11:50:58Z")
Hi! I want to validate values from a form. That wouldn’t be very difficult, but the model I want to polulate is in a polymorphic association! Here are my models: - Document (created\_at, autor, resource\_id, resource\_type) \*\* Folder (name) \*\* Binary (name, data, content\_type) So a document can be either a folder or a binary. But here the problem begins. Folder and Binary both have a “name”-column (this column is not in the “documents”-table), so when users create a folder, they can enter a name. When they upload a file, the “name”-column of the “binaries”-table will be set automatically to the name of the file the user has uploaded. That’s no problem! But I want to validate the name for a folder the user enteres. I have two seperate forms for folder- and binary-creation, and I simply want to validate the presence and the length of a new folder-name. But where does the validation go? And how can I display the error- messages? I tried several things, but when I try to enter a folder without a name there will be no new record in “folders” (which is good!) but no error-message and an entry in the “documents”-table. How can I validate those entries and how can I display error-messages? And how can I prevent inserting “empty” entries to the “documents”- table? Thanks for any help, - Dominik