[SalesForce] How to i invoke a child object trigger when a parent object trigger delete action invoked

I have 3 objects like superParent Parent Child..

I am updating the count of Parent and Child object records on SuperParent in two different fields and it is working fine when i am doing manually.

when Parent Object record is deleted Child object record also deleting because of master detail relation.In that scenario only Parent Records are updating how can i call child object trigger when parent deleted.

Best Answer

On the assumption that your delete logic is embedded in the Child trigger and you want to execute that logic upon some event in the Parent object ....

Triggers can only be invoked when a DML statement occurs and the trigger is registered to handle that DML event (insert, update, delete, undelete - and in before/after such event)
Move your logic out of the Child trigger into a class that can be called both from the Child trigger and from the Parent trigger

More generally, this is covered under the Separation of Concerns pattern as ably described by Andrew Fawcett here.

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[SalesForce] How to count records on a child custom object from the parent

You can use SOQL Aggregate Queries in your Account trigger.

for (AggregateResult ar : [
     Select Count(Id) numRecs, Account__c acctId
     From NPS__c
     Where Account__c In :Trigger.New
     Group By Account__c
]) {
    Id acctId = (Id) ar.get('acctId');
    Account acct = Trigger.newMap.get(acctId);
    acct.NPS_Score_Trigger__c = (Decimal) ar.get('numRecs');
}

This assumes that the API name for Account is Account__c.

[SalesForce] Need to fire trigger on child objects when parent object is updated

On the rollup question only...

This is a case where it is probably worth factoring out the code that does the rollup into a separate class. That then allows the triggers to be fairly simple:

trigger ParentTrigger on Parent__c (before ...) {
    if (change detected) {
        // Trigger objects will be persisted so just copy result
        for (Parent p : ChildRollup.calculateParents(Trigger.newMap)) {
            Trigger.newMap.get(p.Id).Sum__c = p.Sum__c;
        }
    }
}

trigger ParentTrigger on Parent__c (after ...) {
    if (change detected) {
        update ChildRollup.calculateParents(Trigger.newMap);
    }
}

trigger ChildTrigger on Child__c (...) {
    update ChildRollup.calculateParents(Trigger.newMap);
}

and sharing most of the code:

public class ChildRollup {
    public static Parent__c[] calculateParents(Map<Id, Parent__c> parents) {
        return calculateParents(parents.keySet());
    }
    public static Parent__c[] calculateParents(Map<Id, Child__c> children) {
        Set<Id> parentIds = new Set<Id>();
        for (Child__c c : children.values()) {
            parentIds.add(c.Parent__c);
        }
        return calculateParents(parentIds);
    }
    private static Parent__c[] calculateParents(Set<Id> parentIds) {
        Map<Id, Parent__c> parents = new Map<Id, Parent__c>();
        for (Id parentId : parentIds) {
            parents.put(parentId, new Parent__c(Id = parentId, Sum__c = 0.00));
        }
        for (AggregateResult ar : [
                select Parent__c p, sum(Value__c) s
                from Child__c
                where Parent_c in :parentIds
                group by Parent__c
                ]) {
            parents.get((Id) ar.get('p')).Sum__c += (Decimal) ar.get('s');
        }
        return parents.values();
    }
}

Best Answer

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