What are async context managers for database connections?

Question

Accepted Answer

Async context managers manage **async database connections** automatically.

```python
import asyncio
from contextlib import asynccontextmanager

# Using aiopg (async PostgreSQL)
import aiopg

@asynccontextmanager
async def get_connection(dsn):
    conn = await aiopg.connect(dsn)
    try:
        yield conn
    finally:
        await conn.close()

async def main():
    async with get_connection("dbname=mydb") as conn:
        async with conn.cursor() as cur:
            await cur.execute("SELECT * FROM users")
            rows = await cur.fetchall()
            print(rows)

asyncio.run(main())
```

**SQLAlchemy async:**
```python
from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine

engine = create_async_engine("postgresql+asyncpg://user:pass@localhost/db")

async def get_session():
    async with AsyncSession(engine) as session:
        yield session
```

**Benefits:**
- Automatic connection cleanup.
- Transaction management.
- Exception safety.

Python: What are async context managers for database connections?