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can anybody tell me why this trigger only works when the record is created but not when is updated. For example, if I create a new record the trigger will set the buyer name correctly but if I changed the NRProduct__c it will not get the new buyer's name.

I will appreciate any help.

trigger buyerlookupTriggerMWSItem on MWSOrderItem__c (before update, before insert) {

    MWSOrderItem__c[] results =
           [SELECT id , NRProduct__r.Buyer_Lookup__c  
              FROM MWSOrderItem__c
              WHERE id IN

    Map<id,id> Map1 = new Map<id,id>();
    for(MWSOrderItem__c rod : results)

    User s = [SELECT Id FROM User WHERE id IN :Map1.keySet()];
    if(s != null){
        for(MWSOrderItem__c r :{
                r.Buyer_Lookup__c = s.Id;
catch(Exception ex){}
share|improve this question
Are you positive that the Buyer_Lookup__c on the MWSOrderItem__c objects being updated are already null? And do you have any workflow rules with field update actions on MWSOrderItem__c? – greenstork Jul 7 '14 at 22:54
Hi greenstork, we do have some workflows for this Object, do u think that can be the reason the trigger is not updating? – Carlos Jul 7 '14 at 23:42
No, I think the reason was answered by @brovasi. There are a number of issues with your code addressed with the answer given. – greenstork Jul 7 '14 at 23:44
I think your code was working for you as a fluke, as a result of the workflow rules causing the trigger to fire twice but the solution is as brovasi mentioned. – greenstork Jul 7 '14 at 23:45
good to know that, but i am getting an error with that solution, perhaps because NRProduct__c is a master-relation field – Carlos Jul 7 '14 at 23:49
up vote 5 down vote accepted

A few things with your code :

  • try and catch is rarely used in a trigger
  • buyer_lookup is a lookup to user, so why do you want to query the User if you already have the id
  • On before insert, usually you don't query the records themselves, they don't exist yet

UPDATED: Modified the code to include the name of the buyer if you need

Check if the following code is working :

trigger buyerlookupTriggerMWSItem on MWSOrderItem__c (before update, before insert) {
    Map<id,NRProducts__c> nrProducts = new Map<id,NRProducts__c>();
    for(MWSOrderItem__c rod :{
    nrProducts = new Map<ID,NRProduct__c>([select id, Buyer_Lookup__c, Buyer_Lookup__r.Name from NRProducts__c where Id IN :nrProducts.keySet()]);

    for(MWSOrderItem__c rod :
      if(nrProducts.get(rod.NRProduct__c) != null){
          rod.Buyer_Lookup__c = nrProducts.get(rod.NRProduct__c).Buyer_Lookup__c;
          //rod.Buyer_Lookup__c = nrProducts.get(rod.NRProduct__c).Buyer_Lookup__r.Name;
share|improve this answer
i am gonna try ur solution now – Carlos Jul 7 '14 at 23:10
Brovasi, I am getting an error: "Invalid type: NRProduct__c at line 3 column 50." Just you know NRProduct__c field is a master-relation field to the Object NRProducts__c – Carlos Jul 7 '14 at 23:16
Sorry I don't know your data model, so you might need to make a few changes, but the idea is there. – brovasi Jul 7 '14 at 23:20
I appreciate it, and how about the test class for this approach? – Carlos Jul 7 '14 at 23:21
probably insert a NRProduct with a buyer, then insert a MWSOrderItem. Have a try and if you have any question, create a new post. Cheers – brovasi Jul 7 '14 at 23:26

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