# Reservaton Type
**URL:** https://community.glideapps.com/t/reservaton-type/67452
**Category:** Ask for Help
**Created:** [November 1, 2023, 8:09pm UTC](https://community.glideapps.com/t/reservaton-type/67452 "2023-11-01T20:09:51Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Mauricio\_Gonzalez](https://community.glideapps.com/u/Mauricio_Gonzalez)
#### Post date: [November 1, 2023, 8:09pm UTC](https://community.glideapps.com/t/reservaton-type/67452/1 "2023-11-01T20:09:51Z")
Hi!
I would love to get some suggestions on how to best format my booking app.
Context: I am building an advanced management & booking app for a football center.
Problem: I am having a hard time trying to set validations on available times, depending on the reservation type. (e.g., Full field or half field).
If the user selects “half field” at 10AM, I would like the system to show one more slot if any other user wants to reserve the other half. If a user selects “full field”, then I would like to fully reserve that hour!
Ask: Do you have any recommendations on how to set this up on the backend?
Thanks so much in advance!
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### Author:  [@ThinhDinh](https://community.glideapps.com/u/ThinhDinh)
#### Post date: [November 2, 2023, 12:16am UTC](https://community.glideapps.com/t/reservaton-type/67452/2 "2023-11-02T00:16:27Z")
I would have a numerical value to represent “how much” that slot has been booked.
Say for any bookings, “half field” would return 0.5, and “full field” returns 1 in an If-Then-Else column.
For new bookings, use a custom form. Validate the choice against the list of your existing bookings. Use a query to look for the same time slot that the user is choosing, and a rollup to sum the value above.
If the sum is 0, allow them to book both types. If the sum is 0.5, allow them to book a half field, if the sum is 1, don’t allow them to book.
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### Author:  [@Mauricio\_Gonzalez](https://community.glideapps.com/u/Mauricio_Gonzalez)
#### Post date: [November 2, 2023, 1:53pm UTC](https://community.glideapps.com/t/reservaton-type/67452/3 "2023-11-02T13:53:19Z")
This is brilliant - thank you @ThinhDinh! I will give it a try and post here once I test it.
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### Author:  [@ThinhDinh](https://community.glideapps.com/u/ThinhDinh)
#### Post date: [November 3, 2023, 12:58am UTC](https://community.glideapps.com/t/reservaton-type/67452/4 "2023-11-03T00:58:17Z")
> [@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…
You would also need a custom form to validate it, not a normal form.