Custom edit button on custom Table

[DevadharshiG]

I have created custom tables  "Group Table" and "Participant Table" similar to OOB Group and Group Members table. 

Requirement is as below:

Adding the participants via Edit button to any of the group who are already part of some other group should not allow them to add it as well as populate some alert message.

Restricting the addition of participant if part of some other group was achieved it via BR on participant table.

Second part, populating alert message is not able to achieve it.

Is someone already worked on this kind of requirement, please help me out to achieve this?

Thanks in Advance!

[GopikaP]

Hi @DevadharshiG , Can you share the script of the UI Action(Button)? , Also the BR script if possible?

[SairajG]

Client Script (To Show Alert Message):
Create an onSubmit Client Script on the Participant Table.
This script will check if the selected participant is already assigned to a group.
If they are, it will show an error message and stop form submission.

GlideAjax (Server-Side Validation):
Since Client Scripts can't directly query the database, create a Script Include.
The Script Include will check if the participant is already in another group and return true or false.

If you need any help with code please let me know.