Back-End Development Study Guide 2026
Everything you need to pass the Back-End Development exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 Back-End Development Exam Format at a Glance
📚 Back-End Development Topics to Study (38)
✍️ Sample Back-End Development Questions & Answers
1. What is the best way to prevent SQL injection in a back-end application?
Parameterized queries separate SQL code from user data, so the database treats user input as data, not executable code.
2. What is N+1 query problem in ORM usage?
The N+1 problem occurs when fetching a list of N records triggers N additional queries to load their associations, which is solved by eager loading (e.g., JOIN or include).
3. What is the purpose of the SQL EXPLAIN (or EXPLAIN ANALYZE) command?
EXPLAIN displays the query execution plan chosen by the optimizer, revealing index usage, join strategies, and estimated costs.
4. What is the principle of least privilege in back-end security?
The principle of least privilege limits damage from breaches or bugs by ensuring each user and service has only the access rights required for their specific function.
5. What is the primary role of an ORM (Object-Relational Mapper) in back-end development?
An ORM maps relational database tables to objects in code, letting developers interact with the database using their language's syntax instead of raw SQL.
6. What is a refresh token and how does it work alongside an access token?
Refresh tokens are long-lived credentials stored securely that allow clients to obtain new short-lived access tokens when they expire, without requiring the user to log in again.