rb-commons 0.3.4

Commons of project and simplified orm based on sqlalchemy.

RB-Commons

RB-Commons is a lightweight async Python library that simplifies database operations through a clean manager interface built on top of SQLAlchemy's async capabilities. It provides a robust foundation for handling common database operations while maintaining full type safety through Python's typing system.

Features

Async-First Design

• Built on top of SQLAlchemy's async functionality
• Efficient handling of async database operations
• Proper transaction and session management
• Type-safe operations with Generic types

Core Functionality

• CRUD Operations: Complete set of Create, Read, Update, and Delete operations
• Flexible Filtering: Support for dynamic query filtering
• Instance Management: Both instance-level and query-level updates
• Error Handling: Comprehensive error handling with custom exceptions
• Transaction Safety: Automatic rollbacks on failures

Installation

pip install rb-commons

Quick Start

from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String
from rb_commons.orm import BaseManager

# Define your model
Base = declarative_base()

class User(Base):
    __tablename__ = 'users'
    
    id = Column(Integer, primary_key=True)
    name = Column(String)
    email = Column(String)

# Create your manager
class UserManager(BaseManager[User]):
    model = User

# Usage in async context
async def main():
    # Setup database connection
    engine = create_async_engine("postgresql+asyncpg://user:pass@localhost/db")
    async with AsyncSession(engine) as session:
        # Initialize manager
        user_manager = UserManager(session)
        
        # Create user
        user = await user_manager.create(
            name="John Doe",
            email="[e-mail]"
        )
        
        # Get user
        user = await user_manager.get(id=1)
        
        # Filter users
        users = await user_manager.filter(name="John Doe")
        
        # Update user by filters
        updated_user = await user_manager.update_by_filters(
            filters={"id": 1},
            name="Jane Doe"
        )
        
        # Delete user
        success = await user_manager.delete(id=1)

Core Operations

Get and Filter

# Get single instance (returns Optional[ModelType])
user = await user_manager.get(id=1)

# Filter multiple instances (returns List[ModelType])
active_users = await user_manager.filter(is_active=True)

# Check existence
exists = await user_manager.is_exists(email="[e-mail]")

Create

try:
    user = await user_manager.create(
        name="John Doe",
        email="[e-mail]"
    )
except DatabaseException as e:
    print(f"Database error: {e}")
except InternalException as e:
    print(f"Internal error: {e}")

Update

RB-Commons provides three different ways to update records:

# 1. Update by filters - updates records matching filters and returns updated instance
updated_user = await user_manager.update_by_filters(
    filters={"id": 1},
    name="New Name"
)

# 2. Update instance with specific fields
user = await user_manager.get(id=1)
if user:
    updated_user = await user_manager.update(
        instance=user,
        name="New Name"
    )

# 3. Save modified instance
user = await user_manager.get(id=1)
if user:
    user.name = "New Name"
    saved_user = await user_manager.save(user)

Delete

# Delete by ID
success = await user_manager.delete(id=1)

# Delete by filters
success = await user_manager.delete(email="[e-mail]")

# Bulk delete
deleted_count = await user_manager.bulk_delete(is_active=False)

Error Handling

RB-Commons provides custom exceptions for better error handling:

• DatabaseException: For SQLAlchemy and database-related errors
• InternalException: For internal operation errors

try:
    user = await user_manager.create(name="John")
except DatabaseException as e:
    # Handle database errors (e.g., constraint violations)
    print(f"Database error: {e}")
except InternalException as e:
    # Handle internal errors
    print(f"Internal error: {e}")

Method Return Types

• get(): Optional[ModelType]
• filter(): List[ModelType]
• create(): ModelType
• delete(): bool | None
• bulk_delete(): int
• update(): Optional[ModelType]
• update_by_filters(): Optional[ModelType]
• save(): Optional[ModelType]
• is_exists(): bool

Best Practices

1. Choose the Right Update Method:
   • Use update_by_filters() for query-based updates
   • Use update() for updating specific fields of an instance
   • Use save() for saving modified instances
2. Always Use Async Context: The library is designed for async operations, ensure you're running within an async context
3. Session Management: Properly manage your database sessions using async context managers
4. Error Handling: Implement proper error handling using the provided exception classes
5. Type Safety: Utilize the generic typing system for better IDE support and type safety

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

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