Transactions

Run a group of operations atomically, committing together or rolling back as one.

db:transaction(fn)

db:transaction(fn) runs fn atomically: it commits when fn returns and rolls back if fn raises. Operations performed inside fn are transactional automatically.

db:transaction(function()
    from:save():await()
    to:save():await()
end):await()

If from:save() succeeds but to:save() raises, neither change is committed.

Adapter support

db:transaction(fn) throws if the adapter can't run transactions. Check db:supports_transactions() first to branch:

if db:supports_transactions() then
    db:transaction(function()
        from:save():await()
        to:save():await()
    end):await()
else
    from:save():await()
    to:save():await()
end

WARNING

The oxmysql adapter supports transactions; the nanos adapter does not. Guard with db:supports_transactions() if your code must run on either.

See Promises & await for why each operation is awaited, and CRUD & Records for the operations used inside a transaction.