Dynamically defining a database

For even more control over how your database is defined/initialized, you can use the Proxy helper. Proxy objects act as a placeholder, and then at run-time you can swap it out for a different object. In the example below, we will swap out the database depending on how the app is configured: database_proxy = Proxy() # Create a proxy for our db. class BaseModel(Model): class Meta: database = database_proxy # Use proxy for our DB. class User(BaseModel): username = CharField() # Based on configuration, use a different database. if app.config['DEBUG']: database = SqliteDatabase('local.db') elif app.config['TESTING']: database = SqliteDatabase(':memory:') else: database = PostgresqlDatabase('mega_production_db') # Configure our proxy to use the db we specified in config. database_proxy.initialize(database)

Warning

Only use this method if your actual database driver varies at run-time. For instance, if your tests and local dev environment run on SQLite, but your deployed app uses PostgreSQL, you can use the Proxy to swap out engines at run-time.

However, if it is only connection values that vary at run-time, such as the path to the database file, or the database host, you should instead use Database.init(). See Run-time database configuration for more details.