It’s probably fine, but this sort of thing is why transactionAmount and transactionCurrency are better when separated. Consider the case when you’re doing some reporting from your DB based on currency; do you really want to have to deal with one string that contains both or just do a simple WHERE clause?
In our case those are indeed separate in the database, so that we can type the value as a numeric, which is very necessary for many operations. Those fields only get combined in the serialization.
