# Check for existing value **URL:** https://community.glideapps.com/t/check-for-existing-value/35055 **Category:** Ask for Help **Created:** [November 25, 2021, 8:48pm UTC](https://community.glideapps.com/t/check-for-existing-value/35055 "2021-11-25T20:48:23Z") **Posts on this page:** 1 **Showing post:** 2
### Author: ![ThinhDinh](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/thinhdinh/32/49_2.png) [@ThinhDinh](https://community.glideapps.com/u/ThinhDinh) #### Post date: [November 25, 2021, 11:40pm UTC](https://community.glideapps.com/t/check-for-existing-value/35055/2 "2021-11-25T23:40:15Z")
> [@How do I create a custom form?](https://community.glideapps.com/t/how-do-i-create-a-custom-form/25014/): > > I’m just dropping this here so I have something to refer people to when they ask. This is a simple concept app (copyable), that demonstrates the following techniques: Building custom forms for adding and editing list items (as an alternative to the native forms provided by Glide) Preventing duplicate new entries using [User Specific Columns](https://docs.glideapps.com/all/reference/data-editor/user-specific-columns) and [Relations](https://docs.glideapps.com/all/reference/data-editor/computed-columns/relation-column) Enforcing mandatory input items The use of visibility conditions and user specific booleans to control user flow There is nothing particula… Make a custom form, then do a relation from your text entry to the list of existing emails/names. If the relation(s) is/are not empty then you show a text telling the user that the email/name already exists. --- _[View the full topic](https://community.glideapps.com/t/check-for-existing-value/35055)._