What are the types of relationships in a database? ● One-to-One (1:1): Each row in one table is linked to one row in another table. ● One-to-Many (1:M): A row in one table can be linked to many rows in another table. ● Many-to-Many (M:N): Rows in one table can be linked to many rows in another table

nd vice versa. This often requires a junction table.

What interviewers expect

• A clear definition tied to SQL in SQL & Databases projects
• Trade-offs (performance, maintainability, security, cost)
• When you would and would not use it in production

Real-world example

In a production SQL & Databases application, teams apply this when handling user-facing features or integration boundaries. For example, you might use it during a sprint where reliability and observability matter—logging metrics, validating edge cases, and documenting the decision in an ADR so future developers understand why the approach was chosen.

How to explain in the interview

1. Define the concept in one or two sentences.
2. Context — where it fits in SQL & Databases architecture.
3. Example — a specific project, bug, or performance win.
4. Trade-off — what you gain vs what you sacrifice.

Tip: Practice aloud on Toolliyo mock interview or the Interview Q&A section before your real interview.