Drop databases package and use sqlalchemy async instead

0.22.0

🐛 Breaking changes

• Migration from databases library to native async SQLAlchemy

  Version 0.22.0 migrates from the databases library to native async SQLAlchemy using ormar's DatabaseConnection wrapper. This provides better integration with SQLAlchemy's async ecosystem and improved transaction handling and avoid dependency on archived databases library.

• Import changes

  Replace databases import with DatabaseConnection from ormar:

  # ormar < 0.22
  import databases
  database = databases.Database("sqlite:///db.sqlite")
  
  # ormar >= 0.22
  from ormar import DatabaseConnection
  database = DatabaseConnection("sqlite+aiosqlite:///db.sqlite")

• Database URLs require async drivers

  Database connection strings must now use async-compatible drivers:

  • SQLite: sqlite+aiosqlite:// (not sqlite://)
  • PostgreSQL: postgresql+asyncpg:// (not postgresql://)
  • MySQL: mysql+aiomysql:// (not mysql://)

  # ormar < 0.22
  database = databases.Database("sqlite:///db.sqlite")
  
  # ormar >= 0.22
  database = DatabaseConnection("sqlite+aiosqlite:///db.sqlite")

• Engine parameter removed from OrmarConfig

  The engine parameter is no longer needed in OrmarConfig - it's created internally by DatabaseConnection:

  # ormar < 0.22
  import databases
  import sqlalchemy
  
  database = databases.Database("sqlite:///db.sqlite")
  engine = sqlalchemy.create_engine("sqlite:///db.sqlite")
  
  base_ormar_config = ormar.OrmarConfig(
      database=database,
      metadata=sqlalchemy.MetaData(),
      engine=engine,  # <- No longer needed
  )
  
  # ormar >= 0.22
  from ormar import DatabaseConnection
  import sqlalchemy
  
  database = DatabaseConnection("sqlite+aiosqlite:///db.sqlite")
  
  base_ormar_config = ormar.OrmarConfig(
      database=database,
      metadata=sqlalchemy.MetaData(),
      # engine is created internally
  )

• Table creation requires sync engine

  When using metadata.create_all(), you must create a separate sync engine:

  # ormar >= 0.22
  import sqlalchemy
  from ormar import DatabaseConnection
  
  DATABASE_URL = "sqlite+aiosqlite:///db.sqlite"
  database = DatabaseConnection(DATABASE_URL)
  metadata = sqlalchemy.MetaData()
  
  # Create a sync engine for table creation
  sync_engine = sqlalchemy.create_engine(
      DATABASE_URL.replace('+aiosqlite', '')
  )
  metadata.create_all(sync_engine)

✨ Features

• Improved transaction handling

  Transactions now use context variables and SQLAlchemy savepoints for better nested transaction support:

  # Nested transactions with automatic savepoints
  async with database.transaction():
      await Model1.objects.create(...)
  
      async with database.transaction():  # Uses savepoint
          await Model2.objects.create(...)

• Enhanced testing support

  The force_rollback parameter for transactions makes testing easier.
  Like in databases force_rollback can also be used with DatabaseConnection directly to use one global transaction.

  async with database.transaction(force_rollback=True):
      # Your test code - will rollback even on success
      await Model.objects.create(...)

💬 Other

• Improved pyright support - thanks @MaximSrour - #1491