Write a trigger on a custom object that has a lookup field to Account. Count the number of records in the related object that are associated with that account, and update a field on the account with that number. (ie - emmulate a roll-up summary field, on an object that is NOT a master-detail) relationship.
Be sure that the trigger is bulkified (ie - will accept upto 200 triggered records at one-time, with no limit errors).
Write test code coverage, to cover 90%+ of the lines in the trigger.
Be sure that the trigger is bulkified (ie - will accept upto 200 triggered records at one-time, with no limit errors).
Write test code coverage, to cover 90%+ of the lines in the trigger.