SWI-Prolog -- transaction

Documentation
- Reference manual
  - Built-in Predicates
    - Database
      - Managing (dynamic) predicates
        
        Transactions
        
        transaction/1
        
        transaction/2
        
        transaction/3
        
        snapshot/1
        
        current_transaction/1
        
        transaction_updates/1
- Packages

Availability:built-in

transaction_updates(-Updates)

Unify Updates with a list of database updates that would be effectuated if the transaction is going to be committed at this stage. Updates is a list of terms defined below. The elements are sorted on the change generation, i.e., the order in which the operations were performed.

asserta(+ClauseRef)
assertz(+ClauseRef): The given clause will be asserted at the start or end. Note that due to competing transactions the clause may no longer be the first/last clause of the predicate.
erased(+ClauseRef): The given clause will be removed. This may be due to erase/1, retract/1 or retractall/1.