In the preceding code and in the vast majority of Odoo models, classes are based on the models.Model class. These types of model have permanent database persistence: database tables are created for them and their records are stored until explicitly deleted.
But Odoo also provides two other model types to be used: Transient and Abstract models.
Transient models are based on the models.TransientModel class and are used for wizard-style user interaction. Their data is still stored in the database, but it is expected to be temporary. A vacuum job periodically clears old data from these tables. For example, the Load a Language dialog window, found in the Settings | Translations menu, uses a Transient model to store ...
