This is because you did not handle for the bulk insertion of records.

just take list of invoices add your invoices (which has to be updated). Do the updation out side the for loop.

list<invoice__c> lstInvs = new list<invoice__c>(); declare it below the objSet declaration

then in the for loop

objAcc.CC_Expiry_Date__c = objOpp.Expiry_Date__c;

objAcc.Creditcard_Type__c = objOpp.Credit_card_Type__c;

lstInvs.add(objAcc);

then at last update the list (outside for loops)

update lstInvs;

regards,

Shravan

i think i'm doing somethign wrong here

now i get error  Duplicate ID in List, here is my trigger

trigger CC_Exp on Payment__c (after insert, after update) {
Set<id> objSet = new Set<id>();  
list<invoice__c> lstInvs = new list<invoice__c>(); 
for(Payment__c objOpp:trigger.new)

{

objSet.add(objOpp.Invoice__c);

}

List<Invoice__c> myInvoice = [select Id,Status__c from Invoice__c where Id in: objSet];

for(Payment__c objOpp:Trigger.new)

{

for(Invoice__c objAcc: myInvoice)

{

if (objOpp.Payment_Method__c == 'Credit Card') {

{

objAcc.CC_Expiry_Date__c = objOpp.Expiry_Date__c;//
objAcc.Creditcard_Type__c = objOpp.Credit_card_Type__c;//

lstInvs.add(objAcc);


}}}
}
update lstInvs;


}

It is better to check the Payment_Method__c == 'credit card' in the trigger it self.

if(objOpp.Payment_Method__c == 'Credit Card')

{

objSet.add(objOpp.Invoice__c);

}

and remove the first for loop i.e, for(Payment__c objOpp:Trigger.new)

Regards,

Shravan

if i remove the first loop it doe not let me compile, says that objOpp.Invoice__c does not exists.

 i tried differnt way declaring it such as payment__c objSet;

but it tells me duplicate variables.