python-database-patternslisted
Install: claude install-skill aiskillstore/marketplace
# Python Database Patterns
SQLAlchemy 2.0 and database best practices.
## SQLAlchemy 2.0 Basics
```python
from sqlalchemy import create_engine, select
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, Session
class Base(DeclarativeBase):
pass
class User(Base):
__tablename__ = "users"
id: Mapped[int] = mapped_column(primary_key=True)
name: Mapped[str] = mapped_column(String(100))
email: Mapped[str] = mapped_column(String(255), unique=True)
is_active: Mapped[bool] = mapped_column(default=True)
# Create engine and tables
engine = create_engine("postgresql://user:pass@localhost/db")
Base.metadata.create_all(engine)
# Query with 2.0 style
with Session(engine) as session:
stmt = select(User).where(User.is_active == True)
users = session.execute(stmt).scalars().all()
```
## Async SQLAlchemy
```python
from sqlalchemy.ext.asyncio import (
AsyncSession,
async_sessionmaker,
create_async_engine,
)
from sqlalchemy import select
# Async engine
engine = create_async_engine(
"postgresql+asyncpg://user:pass@localhost/db",
echo=False,
pool_size=5,
max_overflow=10,
)
# Session factory
async_session = async_sessionmaker(engine, expire_on_commit=False)
# Usage
async with async_session() as session:
result = await session.execute(select(User).where(User.id == 1))
user = result.scalar_one_or_none()
```
## Model Relationships
```python
from sqlalchemy import ForeignKey
from sqlalchemy.orm import relat