Trigger confusion

Question

trigger to block more than 2 contacts per account. This trigger is working fine on after insert.

But I have confusion that it should be on before insert as we want this trigger to work before inserting account but on after insert this trigger is not working fine as even 100 contacts are getting created of a account by writing script.

trigger BlockMoreThan2ContactOnAccount on Contact (after insert, after update, after undelete) {
  Set<Id> accountIds = new Set<Id>();
  for(Contact record: Trigger.new) {
    accountIds.add(record.AccountId);
  }
  accountIds.remove(null);
  Set<Id> morethan2Contacts = new Map<Id, AggregateResult>([
    SELECT AccountId Id
    FROM Contact
    WHERE AccountId = :accountIds
    GROUP BY AccountId
    HAVING COUNT(Id) > 2]).keySet();
  for(Contact record: Trigger.new) {
    if(moreThan2Contacts.contains(record.AccountId)) {
      record.AccountId.addError('You may not have more than 2 contacts per account.');
    }
  }

Plz check it once.. When this trigger is on before insert.. 3.4.5 n no of contacts are getting created by writing script

account acc=new account(); acc.name='df';

insert acc;

list con=new list(); for(integer i=0;i<3;i++) { contact c=new contact(); c.lastname='sd'; c.accountid=acc.id; con .add(c); } insert con

;

On before this script is working and contacts are getting created.. But on after insert contacts are not getting created. Can anyone clear the doubt

Answer 1

The code more or less works.

for(integer i=0;i<3;i++) checks for number of contacts < 3. While inserting the 3rd contact, the system is still seeing only 2 contacts in the database and therefore proceeds to insert the contact record. You will see failure for the next insertion though.

If you want to restrict only 2 contacts, change the SOQL group count to HAVING COUNT(Id) >= 2]).keySet().