flask_more_smorest.sqla.db

flask_more_smorest.sqla.db = <SQLAlchemy>

Integrates SQLAlchemy with Flask. This handles setting up one or more engines, associating tables and models with specific engines, and cleaning up connections and sessions after each request.

Only the engine configuration is specific to each application, other things like the model, table, metadata, and session are shared for all applications using that extension instance. Call init_app() to configure the extension on an application.

After creating the extension, create model classes by subclassing Model, and table classes with Table. These can be accessed before init_app() is called, making it possible to define the models separately from the application.

Accessing session and engine requires an active Flask application context. This includes methods like create_all() which use the engine.

This class also provides access to names in SQLAlchemy’s sqlalchemy and sqlalchemy.orm modules. For example, you can use db.Column and db.relationship instead of importing sqlalchemy.Column and sqlalchemy.orm.relationship. This can be convenient when defining models.

Parameters:

  • app – Call init_app() on this Flask application now.

  • metadata – Use this as the default sqlalchemy.schema.MetaData. Useful for setting a naming convention.

  • session_options – Arguments used by session to create each session instance. A scopefunc key will be passed to the scoped session, not the session instance. See sqlalchemy.orm.sessionmaker for a list of arguments.

  • query_class – Use this as the default query class for models and dynamic relationships. The query interface is considered legacy in SQLAlchemy.

  • model_class – Use this as the model base class when creating the declarative model class Model. Can also be a fully created declarative model class for further customization.

  • engine_options – Default arguments used when creating every engine. These are lower precedence than application config. See sqlalchemy.create_engine() for a list of arguments.

  • add_models_to_shell – Add the db instance and all model classes to flask shell.

Changed in version 3.1.0: The metadata parameter can still be used with SQLAlchemy 1.x classes, but is ignored when using SQLAlchemy 2.x style of declarative classes. Instead, specify metadata on your Base class.

Changed in version 3.1.0: Added the disable_autonaming parameter.

Changed in version 3.1.0: Changed model_class parameter to accepta SQLAlchemy 2.x declarative base subclass.

Changed in version 3.0: An active Flask application context is always required to access session and engine.

Changed in version 3.0: Separate metadata are used for each bind key.

Changed in version 3.0: The engine_options parameter is applied as defaults before per-engine configuration.

Changed in version 3.0: The session class can be customized in session_options.

Changed in version 3.0: Added the add_models_to_shell parameter.

Changed in version 3.0: Engines are created when calling init_app rather than the first time they are accessed.

Changed in version 3.0: All parameters except app are keyword-only.

Changed in version 3.0: The extension instance is stored directly as app.extensions["sqlalchemy"].

Changed in version 3.0: Setup methods are renamed with a leading underscore. They are considered internal interfaces which may change at any time.

Changed in version 3.0: Removed the use_native_unicode parameter and config.

Changed in version 2.4: Added the engine_options parameter.

Changed in version 2.1: Added the metadata, query_class, and model_class parameters.

Changed in version 2.1: Use the same query class across session, Model.query and Query.

Changed in version 0.16: scopefunc is accepted in session_options.

Changed in version 0.10: Added the session_options parameter.