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Kr ramKr ram 

Duplicate Id in list-Even though code bulkified

Hello gurus,

I am trying to perform a mass update using the data loader,and the below code is throwing duplicate IDs error,
i know i am using SET ,but any pointers on using MAP so that i can fix the error.
All i am doing is copying 2 fields from child(appl__c) to parent(contact)  where the parent is a lookup field in the child table.
Any pointers? thank you!

trigger abre on Appl__c (after insert, after update) {

    Set<Contact> parents = new Set<Contact>();
    for (Appl__c child : {
        if(child.Id != null){
            parents.add(new Contact(Id = child.Contact__c, Admit_Type__c = child.Admit_Type__c,Admit_Term__c=child.Admit_Term__c));

        List<Contact> toUpdate = new List<Contact>();
        update toUpdate;
Himanshu ParasharHimanshu Parashar
Hi Ram,

Try following code
trigger abre on Appl__c (after insert, after update) {

    set<id> ContactIds = new Set<id>();
    Set<Contact> parents = new Set<Contact>();
    for (Appl__c child : {
        if(child.Id != null){

               parents.add(new Contact(Id = child.Contact__c, Admit_Type__c =                  


        List<Contact> toUpdate = new List<Contact>();
        update toUpdate;

Kr ramKr ram
Hi Himanshu,

i am still testing this updated one,but wondering why the one i posted does not work for bulk updates?
thank you again!