How would you debug a production issue related to EF Core in a SOLID Design Principles application?

Short answer: EF Core maps C# entities to tables, tracks changes, and translates LINQ to SQL. Migrations version schema; Include/ThenInclude load graphs.

How to structure your answer (60–90 seconds)

1. Define EF Core in plain language for SOLID Design Principles.
2. Context — where it appears in a typical .NET project.
3. Example — one sentence from work, internship, or a practice app.
4. Trade-off — what you gain vs what you sacrifice.

Real-world example

Loading orders with items using .Include(o => o.Items) avoids N+1 when rendering an invoice list.

Step-by-step talking points

1. Explain DbContext role
2. Contrast eager vs explicit loading
3. Mention migrations and connection resilience
4. Discuss N+1 and how to detect it

Mistakes to avoid

• Tracking large graphs unintentionally
• Client-side evaluation of heavy LINQ
• Forgetting indexes on FK columns

Senior signal: Mention scale, team trade-offs, observability, and how you would mentor a junior on this topic.

Practice aloud. Pair this with the full SOLID Design Principles interview library and timed practice exams on Toolliyo.