You have a table with all your company’s financial transactions. There is another table which references a subset of these financial transactions (ie. transactions with certain properties).

Your current solution to maintain the integrity is to set up a foreign key, referencing the transactions table, and then write a trigger to make sure that any records reference only transactions that have [...]

“Becoming an Oracle guru doesn’t take remarkable intelligence or a pricey Harvard degree, but it does take persistence, drive, and a dedication to excellence.”
- Don Burleson, How to become an Oracle Guru

Despite the appearance of merely trying to promote his team (most notably Steve Karam), Mr. Burleson actually raises some interesting points on a thought-provoking question.