Restrict creation of record if one is already present

[yunus shadman]

I have to restrict creation of "Incident_task" record in the related list of incident if one record for the same incident is already present. 

i wanted to achieve this requirement by removing the "New" button after creation of one record. so that no one can create more than one record in "Incident_task" related list . 

Suppose in the below screenshot , i have crated one record for incident task then just after creation i should not be able to see "New" button to create another task. 

[Tai Vu]

Hi @yunus shadman 

Let's define a Business Rule Before Insert.

You can validate if already existed Incident Task for the Incident.

Sample.

(function executeRule(current, previous /*null when async*/ ) {

    var grIncidentTask = new GlideRecord('incident_task');
	grIncidentTask.addNotNullQuery('incident');
    grIncidentTask.addQuery('incident', current.getValue('incident'));
    grIncidentTask.addQuery('sys_id', '!=', current.getUniqueValue());
    grIncidentTask.setLimit(1);
    grIncidentTask.query();
    if (grIncidentTask.next()) {
		gs.addErrorMessage(gs.getMessage("Incident Task already exists for this Incident " + current.getValue('incident')));
		current.setAbortAction(true);
    }

})(current, previous);

Cheers,

Tai Vu