# How to add rules/conditions to adding table? **URL:** \ **Category:** Ask for Help\ **Created:** [September 15, 2022, 5:01pm UTC](https://community.glideapps.com/t/how-to-add-rules-conditions-to-adding-table/49383 "2022-09-15T17:01:11Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![James1](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/james1/32/38876_2.png) [@James1](https://community.glideapps.com/u/James1)\ **Post date:** [September 15, 2022, 5:01pm UTC](https://community.glideapps.com/t/how-to-add-rules-conditions-to-adding-table/49383/1 "2022-09-15T17:01:11Z")
So, say there is a form for reservation. You can reserve on any date after today. You can also see current reservations. But, if you enter a date that is already reserved, you shouldn’t be able to add to the table. How do you do that? Now, it just adds it to the table. Thanks ---
**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:** [September 16, 2022, 12:19am UTC](https://community.glideapps.com/t/how-to-add-rules-conditions-to-adding-table/49383/2 "2022-09-16T00:19:34Z")
You would need to use a custom form for that. > [@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… If it’s just a date and not including the time, you can: - Convert the chosen date to numerical value (say have a math column to convert it to MMDDYYYY). - Do the same process in the table where you store existing reservations. - Create a relation from the chosen date’s numerical value to the existing reservation dates’ numerical values. - If the relation is not empty, then don’t allow them to add a row. The process is much trickier when you add the time in, with periods of time. ---
**Author:** ![system](https://sea2.discourse-cdn.com/flex002/user_avatar/community.glideapps.com/system/32/53398_2.png) [@system](https://community.glideapps.com/u/system)\ **Post date:** [September 22, 2022, 12:22pm UTC](https://community.glideapps.com/t/how-to-add-rules-conditions-to-adding-table/49383/3 "2022-09-22T12:22:59Z")
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