I created a junction object called Sponsorship__c and have a many-to-many relationship. It is related to Contact through a master-detail relationship and I have another custom object called Sponsored_Child__c which also has a relationship with Sponsorship__c.

What I need to do is create a trigger that updates a Contact field once a new Sponsorship is been created or updated. That field is Child_Names__c and once a Sponsorship is created, the first name(First_Name__c of Sponsored_Child__c) of the Child is concatenated to the field Child_Names__c of Contact.

  • Hi user42387, welcome to SFSE! Please take the time to visit the Help center and read How do I ask a good question. If you post what you've written so far and where you're stuck, I'm confident you'll find plenty of people willing to assist you. SFSE is a Q&A forum where we look to help each other by asking and answering questions about real problems or errors with our code. Posting requests to write code for you generally get closed. Have you gone thru the trigger module in Trailhead?
    – crmprogdev
    Mar 17, 2017 at 13:35

1 Answer 1


One of the things I like to do is add formula fields to my Junction objects to simplify things. So the first step would be to make a field on Sponsorship__c; I'll call it: Sponsored_Child_Name__c.

Formula: Sponsored_Child__c.First_Name__c

Another very important thing to keep in mind is bulkification:

Pseudo Code

trigger triggerName on Sponsorship__c (events) {
if (event) { // trigger.isUpdate, trigger.isBefore, etc
Map<Id, Sponsorship__c> contactToSponsorship = new Map<Id, Sponsorship__c>();
Lisit<Contact> contactsToUpdate = new List<Contact>();

for (Sponsorship__c s : trigger.new) {
contactToSponsorship.put(s.contact__c, s);

for (Contact c : [SELECT Child_Names__c FROM Contact WHERE Id IN :contactToSponsorship.keySet()]) {
c.Child_Names__c += contactToSponsorship.get(c.Id).Sponsored_Child_Name__c;

update contactsToUpdate;

That should get you close.

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