Databases & SQL Vocabulary
Database questions are universal in backend interviews. Use precise English to discuss your approach.
Key Terms
| Term | Meaning |
|---|
| schema | Structure/blueprint of the database tables |
| query | A request to retrieve or modify data |
| index | Data structure that speeds up lookups |
| migration | Script that changes the database schema |
| transaction | A unit of work that is atomic (all-or-nothing) |
| normalization | Organizing data to reduce redundancy |
| foreign key | A field linking two tables |
SQL vs NoSQL Discussion
- "For structured relational data, I would go with PostgreSQL."
- "If we need horizontal scaling and flexible schema, MongoDB makes more sense."
- "Redis is ideal for caching frequently accessed data."
Useful Phrases
- "I added an index on the user_id column to speed up lookups."
- "The query was doing a full table scan — I optimized it by adding a composite index."
- "We wrap the payment logic in a transaction to ensure consistency."