Transactions

By default, ORMithorynque works in “auto-commit” mode: any change to an object in the database is immediately saved in the database.

However, ORMithorynque supports transactions as in the following example:

database.begin_transaction()

# Modify database's objects here

if *something_goes_bad*:
    database.rollback()

else:
    database.end_transaction()

A context / with-statement syntax is also provided:

with database.transaction:
    # Modify database's objects here
    #
    # If *something goes bad*, raise an exception

In addition, when modifying objects inside a transaction, ORMithorynque tries to reduce the number of SQL request executed. For example, in the following example, two UPDATE request are performed, one for each modified attribute:

obj = database[1] # Get an object
obj.name       = "NewName"
obj.first_name = "NewFirstName"

On the contrary, in the following example, a single update request is performed, when the transaction is ended:

with database.transaction:
    obj = database[1] # Get an object
    obj.name       = "NewName"
    obj.first_name = "NewFirstName"

As a consequence, do not expect the database to be updated immediately during a transaction.