Before Insert Trigger not running but compiling

Question

I have a problem with the below code which in turn should run in the form of a Before Insert Trigger on my object Payment Details. This code acrtually compiles with a Before Insert, Before Update Trigger - but the actual calculation or field update doesnot happen. Can you help ?

To give a further background:

Payment_Details object (Child) has a lookup relationship with Payment_Plan (Parent) object which in turn has a lookup relationship with Unit_Detail object (Parent of Payment Plan).

Payment Details has 2 Fields a) Booking_Amount_Due__c and b) Foundation_Amount_Due

Either of these 2 fields should get updated based on the Picklist value field in Payment Plan object Payment_Milestone__c . Picklist value could be Booking or Foundation.

Value of the Booking_Amount_Due or Foundation_Amount_Due fields gets calculated

from the field Base_Apartment_Cost__c in the object Unit Detail.

Trigger:

trigger UpdateAmtDue on Payment_Details__c (before insert, before update) {  
     Payment_Details__c []PD = Trigger.new;  
     MileAmtDUEUpdate.CurMileAmtUpdate(PD);  
}

Code as below

Public class  MileAmtDUEUpdate 

  {
    public static void  CurMileAmtUpdate (Payment_Details__c [] PD ) {

        List<Id> PPIds = new List<Id>();


       For (Payment_Details__c l :PD)     

       {
           PPIds.add (l.Id);
        }



      List<Payment_Details__c> PayDet  = 


  [Select ID, Payment_Plan__c ,Booking_Amount_Due__c , Foundation_Amount_Due__c , 
  Payment_Plan__r.Payment_Milestone__c ,
  Payment_Plan__r.Unit_Name__r.Base_Apartment_Cost__c from Payment_Details__c 
  where id  = : PPIds ];



      List<Payment_Details__c> NewPayDet = New List<Payment_Details__c> () ;


      For (Payment_Details__c PDT : PayDet) 


       { If  (PDT.Payment_Plan__r.Payment_Milestone__c == 'Booking' &&
       PDT.Booking_Amount_Due__c == Null)

     { PDT.Booking_Amount_Due__c = 
      PDT.Payment_Plan__r.Unit_Name__r.Base_Apartment_Cost__c * 0.10 ;

                  NewPayDet.add(PDT) ; }

     else if (PDT.Payment_Plan__r.Payment_Milestone__c == 'Foundation' && 
     PDT.Foundation_Amount_Due__c == Null)         

   { PDT.Foundation_Amount_Due__c = 
   0.10 * PDT.Payment_Plan__r.Unit_Name__r.Base_Apartment_Cost__c ;
                  NewPayDet.add(PDT); }

        }

          Insert NewPayDet ;  

}   
}

Answer 1

One problem I see is in your select statement:

Select ID, Payment_Plan__c ,Booking_Amount_Due__c , Foundation_Amount_Due__c , Payment_Plan__r.Payment_Milestone__c , Payment_Plan__r.Unit_Name__r.Base_Apartment_Cost__c from Payment_Details__c where id = : PPIds ];  

Since you want to query for all updated records you want to use the IN clause not = Also change PPIds to a set vs a list.

Select ID, Payment_Plan__c ,Booking_Amount_Due__c , Foundation_Amount_Due__c , Payment_Plan__r.Payment_Milestone__c , Payment_Plan__r.Unit_Name__r.Base_Apartment_Cost__c from Payment_Details__c where Id IN : PPIds ];

What you can do is a System.debug on your other fields to validate they contain the data that should match the criteria. Could it be possible that Amount defaults to 0 instead of null?

Also since it is before insert in some cases, the Id will not be available yet. Take a look at the docs here for help with trigger context considerations.

Try to instead create a map of the parent then access the map in your for loop and assign your variables.

Answer 2

Public class  NewAmtDUEUpdate 
  {
    public static void  CurMileAmtUpdate (Payment_Details__c [] PD ) {

        Set <Id> PPIds = new Set <Id>();

       For (Payment_Details__c l : PD)

      { If ( l.Payment_Plan__c != Null && l.Booking_Amount_Due__c == Null && 
            l.Foundation_Amount_Due__c == Null) 

               {l.Booking_Amount_Due__c = 0 ;
                l.Foundation_Amount_Due__c = 0 ; 
               PPIds.add (l.Id);}
                                     }

      Map <ID,Payment_Details__c> PayDetMap  

      = New Map <ID,Payment_Details__c> ([Select ID, Payment_Plan__c ,Booking_Amount_Due__c , Foundation_Amount_Due__c , 
            Payment_Plan__r.Payment_Milestone__c ,Payment_Plan__r.Unit_Name__r.Base_Apartment_Cost__c 
            from Payment_Details__c where id In : PPIds ]);


      List<Payment_Details__c> NewPayDet = New List<Payment_Details__c> () ;

      For (Payment_Details__c PDT : PD ) 

        {  Payment_Details__c P = PaydetMap.get(PDT.id) ;

         // If (P.ID != Null)
           //   { P.Booking_Amount_Due__c = 0 ;
             //  P.Foundation_Amount_Due__c = 0 ;}

          If (P.ID != Null && P.Payment_Plan__r.Payment_Milestone__c == 'Booking' &&

             P.Booking_Amount_Due__c == 0 )

     { P.Booking_Amount_Due__c = 
      P.Payment_Plan__r.Unit_Name__r.Base_Apartment_Cost__c * 0.10 ;

                  NewPayDet.add(P) ; }

     else if (P.ID != Null && P.Payment_Plan__r.Payment_Milestone__c == 'Foundation' && 
     P.Foundation_Amount_Due__c == 0 )         

   { P.Foundation_Amount_Due__c = 
   0.10 * P.Payment_Plan__r.Unit_Name__r.Base_Apartment_Cost__c ;
                  NewPayDet.add(P); }

        }
    }   
}