Apex Trigger Between Two Child Objects

Question

I am in the early stages of learning Apex and trying to write some code for a particular scenario. I have two custom objects called Outstanding and Transaction that are both children of an Account. I want to write a trigger that updates the end date of the Outstanding record that has a start date >= the start date on the Transaction and an end date < the end date on the Transaction. I want the end date on the correct Outstanding record to change to the end date on the Transaction.

Example:

Transaction: Start_Date__c (is changed to)= 1/2/2019 End_Date__c=1/31/2020

Outstanding Records:

Start_Date__c 1/4/2018 End_Date__c 1/4/2019
Start_Date__c 1/4/2019 End_Date__c 1/4/2020
Start_Date__c 1/4/2020 End_Date__c 1/4/2021

When the Transaction's start date is changed to 1/2/2019, I want the trigger to find the relevant Outstanding record 2 and update the end date to 12/31/2019.

Hopefully, that makes sense. If it doesn't, please let me know and I'll try to explain it again. Any help would be appreciated. Thanks.

What have you tried? Where are you stuck? If you need help getting started, Trailhead has a good introductory module. — David Reed

prakash chandra hazari prakash chandra hazari · Accepted Answer · 2020-01-21T10:28:24

You have to write a trigger on your Transaction Object on after update context. Please try the below codes.
**Trigger** : 
`trigger TransactionTrigger on Transaction__c (after update) {
    Map<Id,Transaction__c> accTraMap = new Map<Id,Transaction__c>();
    for(Transaction__c transac : trigger.new){
        accTraMap.put(transac.Account__c, transac);
    }
    if(!accTraMap.isEmpty()){
        TransactionTriggerHandler.afterUpdate(accTraMap);
    }
}`
**Class :**

    public class TransactionTriggerHandler {
    public static void afterUpdate(Map<Id,Transaction__c> accTransMap){
        list<Outstanding__c> outstanding = [SELECT Id, Name, StartDate__c, EndDate__c, Account__c 
                                 FROM Outstanding__c where Account__c in:accTransMap.keyset()];

        list<Outstanding__c> outstandingToUpdate = new list<Outstanding__c>();

        for(Outstanding__c o : outstanding){
            if(accTransMap.containsKey(o.Account__c)){
                if(o.StartDate__c >= accTransMap.get(o.Account__c).Start_Date__c && o.EndDate__c < accTransMap.get(o.Account__c).End_Date__c){
                  o.EndDate__c = o.EndDate__c.toStartOfMonth().addDays(-1);
                    outstandingToUpdate.add(o);
                }
            }
        }
        system.debug('\n updated outstanding '+outstandingToUpdate);
        if(!outstandingToUpdate.isEmpty()){
            update outstandingToUpdate;
        }
    }
}

Apex Trigger Between Two Child Objects

1 Answers