A transaction is always either automatic or explicit. If it is automatic, (autocommit), every operation is performed as part of a new transaction that is automatically committed.

Beginning, committing, and rolling back a transaction

begin();

Begin a transaction. No arguments are required. If a transaction is already active, an exception is thrown.

commit(Function(Object error) callback);

Commit a transaction.

This method takes as its sole argument a callback function that returns an error object.

rollback(Function(Object error) callback);

Roll back a transaction. Errors are reported in the callback function.

Transaction information methods

Boolean isActive();

Determine whether or not a given transaction is currently active. Returns true if a transaction is active, and false otherwise.

isActive() requires no arguments.

setRollbackOnly();

Mark the transaction as rollback-only. Once this is done, commit() rolls back the transaction and throws an exception; rollback() rolls the transaction back, but does not throw an exception. To mark a transaction as rollback-only, call the setRollbackOnly() method, as shown here.

This method is one-way; a transaction marked as rollback-only cannot be unmarked. Invoking setRollbackOnly() while in autocommit mode throws an exception. This method requires no arguments.

boolean getRollbackOnly();

Determine whether a transaction has been marked as rollback-only. Returns true if the transaction has been so marked. setRollbackOnly() takes no arguments.