ADD-TRANSACTION-ROLLBACK-HOOK — Specify hooks to be run when rolling back changes.Function
rollback-hookA designator for a function with no required arguments.
databaseA database object. This will default to the value of *default-database*.
resultThe list of currently defined rollback hooks for
            database.
            
        Adds rollback-hook, which should a
        designator for a function with no required arguments, to the
        list of hooks run when rollback is called
        on database which defaults to
        *default-database*.  
(start-transaction)
=> NIL 
(add-transaction-rollback-hook #'(lambda () (print "Successfully rolled back.")))
=> (#<Interpreted Function (LAMBDA # #) {48E37C31}>)
(rollback)
"Successfully rolled back." 
=> NIL