Map lead custom field (Account__c) with Standard Account field 'Parent Account'

Question

I have a requirement in which I have to create a custom lookup field on lead object which selects the account Account__c and during the lead to account conversion I have to map the field with 'Parent Account' field of the account which is a standard field.So i am trying to write the code on before insert trigger that maps the custom lookup field of lead to the standard field of account.

trigger populateParentAccount on Account (before Insert){
    List<Lead> convertedLeads=[SELECT Id, ConvertedAccountID,Agency_account__c FROM Lead WHERE IsConverted=True AND ConvertedAccountId IN :trigger.new];
    Map<ID,ID> acctParentMap=new Map<ID,ID>(); 
    for (lead l: convertedleads){
        acctParentMap.put(l.ConvertedAccountId,l.Agency_account__c);
    } 
    for (account a:trigger.new){
     if (acctParentMap.containsKey(a.Id)){ 
     a.ParentId = acctParentMap.get(a.Id); 
     }
    }
}

But It is not working.. Please help..

Answer 1

This won't work in a before insert trigger, because the Account does not yet have an Id. You will need to use an after insert trigger to detect those records, then perform a recursive update to set the new values.

trigger populateParentAccount on account(after insert) {
  Account[] updates = new Account[0];
  Set<Id> accountIds = new Set<Id>();
  for(Lead record: [SELECT ConvertedAccountId, Agency_Account__c FROM Lead WHERE ConvertedAccountId = :Trigger.new ORDER BY ConvertedDate DESC]) {
    // Avoid multiple leads with same account 
    if(!accountIds.add(record.ConvertedAccountId)) { 
      updates.add(new Account(Id=record.ConvertedAccountId, ParentId=record.Agency_Account__c));
    }
  }
  update updates;
}