Diesel quiz

Test your Diesel knowledge with a free interactive quiz — 20 questions with answers and explanations. No signup needed to play.

What is a `Connection` in Diesel, and why is a connection pool (e.g. via `r2d2` or `deadpool`) commonly layered on top?

1. What is a `Connection` in Diesel, and why is a connection pool (e.g. via `r2d2` or `deadpool`) commonly layered on top?
2. In a Diesel schema, what does the `joinable!` macro (or its modern equivalent, inferred from foreign keys) declare?
3. What does the `table!` macro (or the modern `#[derive(Queryable)]` + schema.rs approach) provide in Diesel?
4. When would a Diesel user reach for `sql_query` or `diesel::sql_types` raw SQL escape hatches?
5. Historically, why did Diesel not support `async`/`await` natively for a long time, unlike newer Rust database crates like `sqlx`?
6. Which databases does Diesel support as first-class backends?
7. What is `#[derive(Insertable)]` used for?
8. What happens if you try to `.select()` a column that doesn't exist on a table in Diesel's typed query builder?
9. What does calling `.load::<User>(&mut conn)` at the end of a Diesel query chain do?
10. What does it mean that Diesel is "compile-time safe"?
11. What is the key architectural difference between Diesel and `sqlx`, another popular Rust database crate?
12. Why might a team choose Diesel over writing raw SQL with a lower-level database driver crate?

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