Validation Rule To Allow Only One Checked Record

Question

I have a custom object Object_X, which has a checkBox field Activate__c. My requirement is that only one Object_X type record can have the Activate__c checked at any given time. So if Object_X already has a record with Activate__c checked, another record with Activate__c checked should not be allowed to be created.

I already have a trigger for this but I'm wondering if there is a way this can be easily achieved by a validation rule.

Answer 1

Disclaimer: Trigger may be the best route for the given situation.

AFAIK You cannot iterate over a set of records using validation rule.Can the activate flag be edited by anyone in the system? If so I would stick to trigger approach, else I can think of a crazy solution which might be an alternative to code approach but more maintenance for the admin every time the flag is changed on the object X.

Step1: Create a custom label which holds the Id of the opportunity where activate = true.

Step2 : Create a validation rule to check both new opptys and updates to existing oppty.

OR(
    AND(
        ISNEW(),
        Activate__c = true
    ), 
    AND( 
        Id != $Label.custom_label_name,
        ISCHANGED(Activate__c ),
        Activate__c = true 
    )
) 

Answer 2

One other validation rule approach would work if the Object_x is a detail in a master detail relationship. You could count the number of detail records that have the Activate__c = true. Then create a validation rule to fire when the count is greater than one.

Answer 3

If you want to ensure only one active record in your entire org, I would use a trigger that uses a service class like below:

public without sharing class ObjectServices
{ // This should be enforced even if someone doesn't have the right visibility
    public static Boolean hasActiveObject
    {
        get
        {
            if (hasActiveObject == null)
            {
                hasActiveObject = [
                    SELECT count() FROM Object_X__c WHERE Activate__c = true
                ] > 0;
            }
            return hasActiveObject;
        }
        private set;
    }

    public static void validateActiveObjects(List<Object_X__c> records)
    {
        if (!hasActiveObject) return;
        for (Object_X__c record : records)
        {
            if (record.Activate__c)
                record.addError(Label.Only_One_Active_Object);
        }
    }
}

Answer 4

You can check like this

    List<Object__x> objList = [SELECT ID,Activate__c WHERE Activate__c = true];
if(objList.size()>0){
   here you can insert new record in Object__x
}