sqlactive 0.1.0

SQLActive is a lightweight and asynchronous ActiveRecord-style wrapper for SQLAlchemy. Bring Django-like queries, automatic timestamps, nested eager loading, and dictionary serialization for SQLAlchemy models.

SQLActive

SQLActive is a lightweight and asynchronous ActiveRecord-style wrapper for SQLAlchemy. Bring Django-like queries, automatic timestamps, nested eager loading, and dictionary serialization for SQLAlchemy models.

Heavily inspired by sqlalchemy-mixins.

Documentation: https://daireto.github.io/sqlactive/

Table of Contents

• Features
• Installation
• Usage
  • 1. Define the Models
  • 2. Initialize the Database
  • 3. Perform CRUD Operations
  • 4. Perform Bulk Operations
  • 5. Perform Queries
  • 6. Perform Native Queries
  • 7. Manage Timestamps
  • 8. Serialization and Deserialization
• Testing
  • Unit Tests
  • Coverage
  • Lint
• Documentation
• Contributing
• License
• Support

Features

• Asynchronous Support: Async operations for better scalability.
• ActiveRecord-like methods: Perform CRUD operations with a syntax similar to Peewee.
• Django-like queries: Perform intuitive and expressive queries.
• Nested eager loading: Load nested relationships efficiently.
• Automatic timestamps: Auto-manage created_at and updated_at fields.
• Dictionary serialization: Convert models to JSON-friendly dictionaries with ease.

Installation

You can simply install sqlactive from the PyPI:

pip install sqlactive

Usage

1. Define the Models

The ActiveRecordBaseModel class provides a base class for your models.

It inherits from:

• ActiveRecordMixin: Provides a set of ActiveRecord-like helper methods for interacting with the database.
• TimestampMixin: Adds the created_at and updated_at timestamp columns.
• SerializationMixin: Provides serialization and deserialization methods.

It is recommended to define a BaseModel class that inherits from ActiveRecordBaseModel and use it as the base class for all models as shown in the following example:

from sqlalchemy import String, ForeignKey
from sqlalchemy.orm import Mapped, mapped_column, relationship
from sqlactive import ActiveRecordBaseModel


# Define a base class for your models (recommended)
class BaseModel(ActiveRecordBaseModel):
    __abstract__ = True


# Define the models
class User(BaseModel):
    __tablename__ = 'users'

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True, index=True)
    username: Mapped[str] = mapped_column(String(18), nullable=False, unique=True)
    name: Mapped[str] = mapped_column(String(50), nullable=False)
    age: Mapped[int] = mapped_column(nullable=False)

    posts: Mapped[list['Post']] = relationship(back_populates='user')
    comments: Mapped[list['Comment']] = relationship(back_populates='user')


class Post(BaseModel):
    __tablename__ = 'posts'

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True, index=True)
    title: Mapped[str] = mapped_column(String(100), nullable=False)
    body: Mapped[str] = mapped_column(nullable=False)
    rating: Mapped[int] = mapped_column(nullable=False)
    user_id: Mapped[int] = mapped_column(ForeignKey('users.id'))

    user: Mapped['User'] = relationship(back_populates='posts')
    comments: Mapped[list['Comment']] = relationship(back_populates='post')


class Comment(BaseModel):
    __tablename__ = 'comments'

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True, index=True)
    body: Mapped[str] = mapped_column(nullable=False)
    post_id: Mapped[int] = mapped_column(ForeignKey('posts.id'))
    user_id: Mapped[int] = mapped_column(ForeignKey('users.id'))

    post: Mapped['Post'] = relationship(back_populates='comments')
    user: Mapped['User'] = relationship(back_populates='comments')

[!WARNING] When defining a BaseModel class, don't forget to set __abstract__ to True in the base class to avoid creating tables for the base class.

[!TIP] The models can directly inherit from the ActiveRecordBaseModel class:

from sqlactive import ActiveRecordBaseModel

class User(ActiveRecordBaseModel):
    __tablename__ = 'users'
    # ...

However, it is recommended to define a base model class for your models and inherit from it.

Your base model class can also inherit directly from the mixins. For example, if you don't want to implement automatic timestamps don't inherit from ActiveRecordBaseModel class. Instead, inherit from ActiveRecordMixin and/or SerializationMixin:

from sqlactive import ActiveRecordMixin, SerializationMixin

class BaseModel(ActiveRecordMixin, SerializationMixin):
    __abstract__ = True

2. Initialize the Database

from asyncio import current_task
from sqlalchemy.ext.asyncio import (
    create_async_engine,
    async_sessionmaker,
    async_scoped_session,
)
from sqlactive import ActiveRecordBaseModel

# Connect to the database
DATABASE_URL = 'sqlite+aiosqlite://'
async_engine = create_async_engine(DATABASE_URL, echo=False)
async_sessionmaker = async_sessionmaker(
    bind=async_engine,
    expire_on_commit=False,
)
async_scoped_session = async_scoped_session(
    async_sessionmaker,
    scopefunc=current_task,
)

# Set the session
BaseModel.set_session(async_scoped_session)

# Initialize the tables
async with async_engine.begin() as conn:
    await conn.run_sync(BaseModel.metadata.create_all)

The use of the expire_on_commit flag is explained in the warning of this section.

[!TIP] Use the DBConnection class as a shortcut to initialize the database. The DBConnection class is a wrapper around the async_engine, async_sessionmaker and async_scoped_session objects:

from sqlactive import DBConnection

DATABASE_URL = 'sqlite+aiosqlite://'
conn = DBConnection(DATABASE_URL, echo=False)
await conn.init_db(BaseModel)

Check the documentation of DB Connection Helper for more information.

3. Perform CRUD Operations

user = await User.insert(username='John1234', name='John Doe', age=25)
user  # <User #1>

user.name = 'Johnny Doe'
user.age = 30
await user.save()
user.name  # Johnny Doe

user = await User.get(1)
user  # <User #1>

await user.update(name='John Doe', age=20)
user.age  # 20

await user.delete()

[!CAUTION] The delete() and remove() methods are not soft deletes methods. Both of them will permanently delete the row from the database. So, if you want to keep the row in the database, you can implement a custom soft delete method, i.e. using save() method to update the row with a flag indicating if the row is deleted or not (i.e. a boolean is_deleted column).

[!TIP] Check the Active Record Mixin API Reference to see all the available methods.

4. Perform Bulk Operations

users = [
    User(username='John1234', name='John Doe', age=20),
    User(username='Jane1234', name='Jane Doe', age=21),
    User(username='Bob1234', name='Bob Doe', age=22),
]

await User.insert_all(users, refresh=True)
users = await User.find(username__endswith='Doe').all()
users  # [<User #1>, <User #2>]

await User.delete_all(users)

users = await User.find(username__endswith='Doe').all()
users  # []

[!WARNING] When calling bulk operation methods, i.e. save_all, insert_all and update_all, the refresh flag must be set to True in order to access the updated attributes of the affected rows.
NOTE: This may lead to a higher latency due to additional database queries.

users = [
    User(username='John1234', name='John Doe', age=20),
    User(username='Jane1234', name='Jane Doe', age=21),
    # ...,
]
await User.save_all(users, refresh=True)
users[0].updated_at
# 2024-12-28 23:00:51

If refresh is not set to True, a sqlalchemy.orm.exc.DetachedInstanceError may be raised when trying to access the updated attributes because the instances are detached (unavailable after commit).

users = [
    User(username='John1234', name='John Doe', age=20),
    User(username='Jane1234', name='Jane Doe', age=21),
    # ...,
]
await User.save_all(users)
users[0].updated_at
# Traceback (most recent call last):
#     ...
# sqlalchemy.orm.exc.DetachedInstanceError: Instance <User ...> is not bound
# to a Session; attribute refresh operation cannot proceed
# (Background on this error at: https://sqlalche.me/e/20/bhk3)

Another option is to set the expire_on_commit flag to False in the async_sessionmaker when initializing the database. However, this does not update the instances after commit. It just keeps the instances available after commit.

async_sessionmaker = async_sessionmaker(
    bind=async_engine,
    expire_on_commit=False,
)

[!TIP] Check the Active Record Mixin API Reference to see all the available methods.

5. Perform Queries

Perform simple and complex queries, eager loading, and dictionary serialization:

from sqlactive import JOINED, SUBQUERY

user = await User.where(name='John Doe').first()
user  # <User #1>

posts = await Post.where(rating__in=[2, 3, 4], user___name__like='%Bi%').all()
posts  # [<Post #1>, <Post #2>, <Post #3>]

posts = await Post.sort('-rating', 'user___name').all()
posts  # [<Post #3>, <Post #1>, <Post #2>, <Post #4>, ...]

comments = await Comment.join(Comment.user, Comment.post).unique_all()
comments  # [<Comment 1>, <Comment 2>, <Comment 3>, <Comment 4>, <Comment 5>, ...]

user = await User.with_subquery(User.posts).first()
user  # <User #1>
user.posts  # [<Post #1>, <Post #2>, <Post #3>]

schema = {
    User.posts: JOINED,
    User.comments: (SUBQUERY, {
        Comment.post: SELECT_IN
    }),
}
user = await User.with_schema(schema).unique_first()
user.comments[0].post.title  # Lorem ipsum

[!WARNING] All relations used in filtering/sorting/grouping should be explicitly set, not just being a backref. This is because sqlactive does not know the relation direction and cannot infer it. So, when defining a relationship like:

class User(BaseModel):
    # ...
    posts: Mapped[list['Post']] = relationship(back_populates='user')

It is required to define the reverse relationship:

class Post(BaseModel):
    # ...
    user: Mapped['User'] = relationship(back_populates='posts')

[!TIP] Check the Active Record Mixin API Reference to see all the available methods.

For more flexibility, the low-level filter_expr, order_expr, column_expr and eager_expr methods can be used.

Example of filter_expr method usage:

Post.filter(*Post.filter_expr(rating__gt=2, body='text'))
# or
session.query(Post).filter(*Post.filter_expr(rating__gt=2, body='text'))

It's like filter in SQLALchemy, but also allows magic operators like rating__gt.

[!IMPORTANT] Low-level filter_expr, order_expr, column_expr and eager_expr methods are very low-level and does NOT do magic Django-like joins. Use smart_query for that:

query = User.smart_query(
    criterion=(or_(User.age == 30, User.age == 32),),
    filters={'username__like': '%8'},
    sort_columns=(User.username,),
    sort_attrs=('-created_at',),
    group_columns=(User.username,),
    group_attrs=['age'],
    schema={
        User.posts: JOINED,
        User.comments: (SUBQUERY, {
            Comment.post: SELECT_IN
        }),
    },
)

[!TIP] Check the Smart Query Mixin API Reference for more details about the smart_query method and the low-level methods.

6. Perform Native Queries

Perform native SQLAlchemy queries using the execute method:

    from sqlalchemy import select, func
    from sqlactive import execute

    query = select(User.age, func.count(User.id)).group_by(User.age)
    result = await execute(query)
    # [(20, 1), (22, 4), (25, 12)]

If your base model is not ActiveRecordBaseModel you must pass your base model class to the base_model argument of the execute method:

    from sqlalchemy import select, func
    from sqlactive import ActiveRecordBaseModel, execute

    # Note that it does not matter if your base model
    # inherits from `ActiveRecordBaseModel`, you still
    # need to pass it to this method
    class BaseModel(ActiveRecordBaseModel):
        __abstract__ = True

    class User(BaseModel):
        __tablename__ = 'users'
        # ...

    query = select(User.age, func.count(User.id)).group_by(User.age)
    result = await execute(query, BaseModel)
    # [(20, 1), (22, 4), (25, 12)]

7. Manage Timestamps

Timestamps (created_at and updated_at) are automatically managed:

user = await User.insert(username='John1234', name='John Doe', age=25)
user.created_at  # 2024-12-28 23:00:51
user.updated_at  # 2024-12-28 23:00:51

await asyncio.sleep(1)

await user.update(name='Johnny Doe')
user.updated_at  # 2024-12-28 23:00:52

[!TIP] Check the TimestampMixin class to know how to customize the timestamps behavior.

8. Serialization and Deserialization

Models can be serialized and deserialized using the to_dict and from_dict methods:

user = await User.insert(username='John1234', name='John Doe', age=25)
user_dict = user.to_dict()
user_dict  # {'id': 1, 'username': 'John1234', 'name': 'John Doe', ...}

user = User.from_dict(user_dict)
user.name  # John Doe

Also, models can be serialized and deserialized using the to_json and from_json methods:

user = await User.insert(username='John1234', name='John Doe', age=25)
user_json = user.to_json()
user_json  # {"id": 1, "username": "John1234", "name": "John Doe", ...}

user = User.from_json(user_json)
user.name  # John Doe

Testing

Unit Tests

To run the tests, simply run the following command from the root directory:

python -m unittest discover -s tests -t .

To run a specific test, use the following command:

python -m unittest tests.<test_name>

Available tests:

• test_active_record.py
• test_db_connection.py
• test_execute.py
• test_inspection.py
• test_serialization.py
• test_smart_query.py

Coverage

First, install the coverage package:

pip install coverage

To check the coverage, run the following command:

python -m coverage run -m unittest discover -s tests -t .

To generate the coverage report, run the following command:

python -m coverage report -m

To generate the HTML report, run the following command:

python -m coverage html -d htmlcov

Lint

First, install the ruff package:

pip install ruff

To check the code style, run the following command:

python -m ruff check .

Documentation

Find the complete documentation here.

Contributing

Please read the contribution guidelines.

License

This project is licensed under the MIT License. See the LICENSE file for details.

Support

If you find this project useful, give it a ⭐ on GitHub to show your support!

Also, give it a ⭐ to sqlalchemy-mixins which inspired this project!