- add db key valprocedure
- add* db key valprocedure
add is like store, but only makes a change if the key did not exist. It returns #f if the key did exist, and #t if it did not.
add* is like add, but raises an exception if the key already exists.
add is like store, but only makes a change if the key did not exist. It returns #f if the key did exist, and #t if it did not.
add* is like add, but raises an exception if the key already exists.