Databases & Data — Chapter Quiz

Question 1

1

Which is the safest way to query Postgres with user input?

Apool.query(SELECT * WHERE id = ${id})Bpool.query("SELECT * WHERE id = $1", [id])CManually escape with replaceDUse eval on the query

Parameterized queries. Never concatenate user input into SQL — that's SQL injection.

Question 2

2

SQLite is well-suited to a moderately-trafficked single-server app.

TTrueFFalse

SQLite handles ~10K writes/sec on good hardware. Plenty for single-server apps, internal tools, and edge databases.

Question 3

3

What is Redis primarily used for in Node apps?

AThe primary system of recordBIn-memory cache, sessions, rate limiting, pub/sub, queuesCStatic-file servingDTypeScript compilation

Redis is the swiss-army knife of in-memory data — caches, session storage, rate-limit counters, pub/sub channels, queues.

Question 4

4

Why use BullMQ for background jobs instead of setTimeout?

ABullMQ is fasterBPersistence, retries, scheduling, scaling across serversCsetTimeout is deprecatedDBullMQ is built into Node

Background queues (BullMQ + Redis) survive restarts, retry on failure, scale across workers, and support scheduling.

Question 5

5

Best pattern for large file uploads to your Node app?

AStream through Node to diskBBuffer everything in memoryCGenerate a presigned S3 URL and have the client upload directlyDStore in your DB as bytea

Presigned URLs let clients upload directly to object storage, bypassing your Node servers entirely.

Question 6

6

Schema changes recorded as numbered scripts are called database ___.

Migrations are versioned, ordered SQL files (or DSL changes) that bring the schema forward (and sometimes backward).

Question 7

7

MongoDB stores documents as:

ARows in tablesBJSON-like objects with flexible schemaCKey-value pairs onlyDXML

Documents are JSON-like (technically BSON). Schema is flexible by default — Mongoose adds optional schema validation.

Question 8

8

Which describe ORMs/query builders for Node + TypeScript?

Select all that apply.

ADrizzle — close to SQL, TS-nativeBPrisma — schema DSL with generated clientCKysely — typed query builderDpg — raw driver

Drizzle, Prisma, and Kysely are ORMs/query-builders with TS type generation. pg is the raw Postgres driver — no abstractions.

Test what you learned.