Hi,

We've been working on a trigger which creates a contract upon an Opportunity being complete and 'Closed Won'. We've managed to get the record to create and copy over important info, although we can't manage to figure the validation logic. Granted we have little apex knowledge and therefore we've attempted to put most of the logic outside the trigger and within a workflowed checkbox on the Opportunity.

However, this don't eliminate the duplication of records if the user edits a Won opportunity. I know the better versed Salesforce developer would have the list check the record doesn't exist in the first place before the trigger even starts and therefore we're reaching out hoping you guys could support us in finishing this piece of work.

Any help or advice would be gratefully appreciated. 

Kev