Filter to exclude a related entities instances

[tanya]

As I understand, you want, SIM has only one FORMREGO
than you need a hook for SIM and checking looks like this

$regoformId = $entity->get('fORMREGOId')
if ($regoformId) {
   throw \Error('This SIM is used in other FORMREGO');
}

(https://github.com/php-fig/fig-stand...ng-standard.md)

[iceman17]

Hi Tanya,
Thank you for responding.

How do a check if the linked field is null?.
Here are my entities and the hook I created.

[tanya]

Hello Samantha.

You can create a filter for SIM where you check if registrationId is null. http://forum.espocrm.com/forum/devel...-custom-entity http://forum.espocrm.com/forum/devel...-for-drop-down
And you can create beforeSave hook, where you check if registrationId is changed. If yes, throw an error https://www.espocrm.com/documentatio...lopment/hooks/

[iceman17]

I create two entities "Registration" and "SIM". Then set a relationship between them, One-to-Many. ie. "Registration" (1 <----------> M) "SIM"

How can I prevent an instance of SIM to be linked to Registration a second time? for example, say if (SIM instance #1) 78880183 is linked to Registration(instance #1) then (Registration instance #2) should not be able to link (SIM instance #1) 78880183 again.

Kind regards
Samantha