Hi guys,

I wrote a trigger to count the number of child Accounts in the hierarchy and store it in a custom field in the Parent Account.
Trigger works fine, except when I remove the parent-child mapping from one of the child Accounts ("deparent"). The count does not go down.
I'm pretty sure I'm overlooking something here. Any help appreciated.
Thank you !!
 

trigger countChildAcc on Account (after Insert, after Update) {
    Set<Id> Ids= new Set<Id>();
    List<Account> acclist = new List<Account>();
    Integer count = 0;
    
    if(Trigger.isInsert || Trigger.isUpdate){
        for(Account acc: Trigger.new){
            if(acc.ParentId!=null)
                Ids.add(acc.ParentId);
            acclist.add(acc);
        }
    }
    
    if(Trigger.isDelete){
        for(Account acc: Trigger.old){
            if(acc.ParentId!=null)
                Ids.add(acc.ParentId);
            acclist.add(acc);
        }
    }
        
    if(Ids.size()>0){
        List<Account> accChild = new List<Account>([SELECT Id,ParentId FROM Account WHERE ParentId IN: Ids]);
        List<Account> accParent = new List<Account>([SELECT Id,No_of_Child_Accounts__c FROM Account WHERE Id IN: Ids]);
        for(Account ac: accParent){
            count =0;
            for(Account acChild: accChild){
                if(acChild.ParentId == ac.Id)
                    count++;
            }
            ac.No_of_Child_Accounts__c = count;            
        }
        try{
            upsert accParent;
        }catch(DMLException ex){
            System.debug('Exception is '+ex);
        }
    }
}

Simply put the following formula into a formula field of type "Text":

 

Id
& MID("ABCDEFGHIJKLMNOPQRSTUVWXYZ012345",(
    IF(FIND(MID(Id,1,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,1,0)
    +IF(FIND(MID(Id,2,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,2,0)
    +IF(FIND(MID(Id,3,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,4,0)
    +IF(FIND(MID(Id,4,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,8,0)
    +IF(FIND(MID(Id,5,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,16,0)
    )+1,1)
& MID("ABCDEFGHIJKLMNOPQRSTUVWXYZ012345",(
    IF(FIND(MID(Id,6,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,1,0)
    +IF(FIND(MID(Id,7,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,2,0)
    +IF(FIND(MID(Id,8,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,4,0)
    +IF(FIND(MID(Id,9,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,8,0)
    +IF(FIND(MID(Id,10,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,16,0)
    )+1,1)
& MID("ABCDEFGHIJKLMNOPQRSTUVWXYZ012345",(
    IF(FIND(MID(Id,11,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,1,0)
    +IF(FIND(MID(Id,12,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,2,0)
    +IF(FIND(MID(Id,13,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,4,0)
    +IF(FIND(MID(Id,14,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,8,0)
    +IF(FIND(MID(Id,15,1), "ABCDEFGHIJKLMNOPQRSTUVWXYZ")>0,16,0)
    )+1,1)

 

This is an optimized version of the code example "BPS: 18 digit external ID within the UI" you can find on the Online Help, but unlike the example provided there, it is small enough to fit into a formula field. Also, this code doesn't contain the error found in the online help example, where the second character byte equivalent of the first 5-character chunk was "4" instead of "2". I'd be more than happy if someone could come up with an even shorter version of this formula...Still, I hope you can use this.

 

Cheers,

Erik Mittmeyer