Async database with databases library in FastAPI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main benefit of using the databases library in FastAPI?

The databases library allows asynchronous interaction with databases, enabling non-blocking database queries that improve performance and scalability in FastAPI applications.

beginner

How do you create a database connection using the databases library?

You create a connection by instantiating Database with a database URL string, for example: database = Database('sqlite:///test.db').

intermediate

Which FastAPI event handlers are used to connect and disconnect the database asynchronously?

Use @app.on_event('startup') to connect the database and @app.on_event('shutdown') to disconnect it, ensuring proper resource management.

intermediate

How do you execute a simple SELECT query asynchronously with the databases library?

Use await database.fetch_all(query) where query is a SQLAlchemy Core select statement or raw SQL string.

beginner

Why is it important to use async/await with the databases library in FastAPI?

Because the library is designed for asynchronous operations, using async/await prevents blocking the event loop, allowing FastAPI to handle many requests efficiently.

What does the databases library primarily provide for FastAPI?

A Frontend UI components

B Synchronous ORM features

C Static file serving

D Asynchronous database access

The databases library is designed for async database access, not UI or static files.

Which method connects the database asynchronously in FastAPI using databases?

A database.connect()

B database.open()

C database.start()

D database.init()

The correct method to connect is await database.connect().

Where should you place the database connection code in a FastAPI app?

A Inside <code>@app.on_event('shutdown')</code>

B Inside <code>@app.on_event('startup')</code>

C In the global scope without async

D Inside route handlers only

Connecting the database on startup ensures it is ready before handling requests.

Which keyword is essential when calling database methods from the databases library?

A await

B yield

C return

D async

Database calls are async and must be awaited.

What type of database URLs can the databases library handle?

A Only NoSQL databases

B Only SQLite

C PostgreSQL, MySQL, SQLite, and others

D Only in-memory databases

The library supports multiple SQL databases via URLs.

Explain how to set up and use the databases library asynchronously in a FastAPI app.

Think about app lifecycle and async calls.

Describe why asynchronous database access improves FastAPI app performance.

Compare blocking vs non-blocking operations.