Most likely you will regenerate the model after making changes to the database. So do not need to.
The model is primary. You work with a model, you do not need to work directly with the database. There are migrations to maintain the database and model. For example, the doctrine / migrations package allows you to automatically generate SQL migrations based on changes in the model.
Those. The overall process should be:
- Create / Edit Model
- Write or generate migration
- Perform migration to the database.
http://symfony.com/doc/current/bundles/DoctrineMigrationsBundle/index.html