SQLAlchemy

https://auth0.com/blog/sqlalchemy-orm-tutorial-for-python-developers/

1. Engines: db connection

Engines = manage Pools and Dialects.

engine = create_engine('postgresql://usr:pass@localhost:5432/sqlalchemy')

creating an engine does not connect to the database instantly

Pool = to improve performance.

1. Opening and maintaining new connections is expensive

2. Easier management of # of connections simultaneously.

Dialects = adopt to different DB.

2. Session vs Connection

session = exec ORM sql query

connection = exec RAW sql query

3. Sessions: sync orm & db

1. modifications ORM tracked & applied to DB.

2. guarantee the database consistency.

# create a configured "Session" class
Session = sessionmaker(bind=engine)

# create a Session
session = Session()

4. Base: base class for all models

Base = declarative_base()