Quickstart

alchemical-storage is a library intended to bridge CRUD operations with SQLAlchemy query constructs

Install

pip install alchemical-storage

Basic Usage

alchemical-storage assumes that you have set up a session (or scoped_session) for your database. This is assumed to have been imported as session in the following example. The table for the defined model is also assumed to be in the database.

1. Set up the model.

   """package/models.py"""
   from sqlalchemy import orm
   
   class Model(orm.DeclarativeBase):
       """Model class"""
       __tablename__ = 'models'
       attr: orm.Mapped[int] = orm.mapped_column(primary_key=True)
       attr2: orm.Mapped[int]
       attr3: orm.Mapped[str]
   

2. Set up the storage schema. The Meta class in the schema should set load_instance to True.

   """package/schema.py"""
   from marshmallow_sqlalchemy import SQLAlchemyAutoSchema
   from package import Model
   
   class ModelSchema(SQLAlchemyAutoSchema):
       """Model storage schema"""
       class Meta:
           model = Model
           load_instance = True
   

3. Create a DatabaseStorage instance. Set the primary_key keyword argument (defaults to 'slug') to the primary key of the model.

   """___main___.py"""
   from package import models
   from package.schema import ModelSchema
   storage = DatabaseStorage(
       session, models.Model, ModelSchema, primary_key="attr",)
   

4. Use the DatabaseStorage instance.

   # __main__.py continued...
   
   storage.get(1)  # Gets a record from the database
   storage.put(2, {'attr2': 1, 'attr3': 'test'})  # Puts a record to the database
   storage.patch(1, {'attr2': 42})  # Update a record in the database
   storage.delete(1)  # Delete a record from the database
   storage.index()  # Get an index of records from the database
   

5. Commit changes to the database.

   session.commit()
   

License

MIT License. See LICENSE file for more details.