Where is the record that is being saved?
The Trigger keyword comes in handy as well and gives us access to current record values (and even to old ones):
1. trigger OpportunityTrigger on Opportunity (before insert, before 2. update, before delete, after insert, after update, 3. after delete, after undelete) { 4. 5. //current record (supposing only one opportunity can be saved at once) 6. Opportunity currentOpp = Trigger.new[0]; 7. 8. //treating before and after events separately 9. if(Trigger.isBefore){10. 11. //following logic 0runs in before insert and update12. if(Trigger.isInsert || Trigger.isUpdate){13. 14. //error if opportunity has a negative amount15. if(currentOpp.Amount <= 0){16. //the addError() method is used ...
