Trigger to update child with parent values

Question

I currently have this trigger which updates the Parent of the record being saved with field values from the GRANDparent of the record being saved :

trigger updateParentwithGrandparent on Grandchild__c (after insert) {

    // Get a list of all Parent Ids
    Set<Id> parentIds = new Set<Id>();
    for (Grandchild__c gc : trigger.new) {
        parentIds.add(gc.MyParent__c);
    }

    // Get a map of all Parents with Grandparent field information
    Map<Id, Parent__c> parentsById = new Map<Id, Parent__c>();
    parentsById.putAll([SELECT Id, MyParent__r.MyField__c FROM Parent__c WHERE Id IN :parentIds]);

    // Loop through each parent and update Parent.MyField__c from Grandparent.MyField__c
    List<Parent__c> parentsToUpdate = new List<Parent__c>();
    for (Id parentId : parentsById.keySet()) {
        Parent__c parent = new Parent__c();
            parent.Id = parentId;
            parent.MyField__c = parentsById.get(parentId).MyParent__r.MyField__c;
        parentsToUpdate.add(parent);
    }

    // Update Parents (bulkified)
    update parentsToUpdate;

}

So it looks up 2 levels of hierarchy and pulls those values down one level to its parent.

But now I am attempting to adapt this code so it would instead update the current record with values from its Parent.

In other words, there is no need for a Grandparent. It will only be looking up one level of hierarchy and pulling those field values into the current record which is being saved.

Can anybody help with this ? I'm confused on how to do this.

Thank you very much for your time and effort.

Answer 1

    trigger updatechildwithparent on child__c (before insert) {

   // Get a list of all Parent Ids
   Set<Id> parentIds = new Set<Id>();
    for (child__c chld : trigger.new) {
      parentIds.add(chld.MyParent__c);
   }

   // Get a map of all Parents with field information
Map<Id, Parent__c> parentsById = new Map<Id, Parent__c>();
parentsById.putAll([SELECT Id, MyParentfield1__c,MyParentfield2__c FROM Parent__c WHERE Id IN :parentIds]);

 for(child__c chld:trigger.new()){ 
      chld.chldfield1__c=parentsById.get(chld.MyParent__c).MyParentfield1__c;
      chld.chldfield2__c=parentsById.get(chld.MyParent__c).MyParentfield2__c;
   }

}

If fields are of currency type be sure to check null pointers .