Welcome to your interview.
The question is on your right: OLTP vs OLAP Database Design. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
In data engineering interviews, you are often expected to distinguish systems built for operational transactions from systems built for analytics. This matters because the same data can be modeled very differently depending on whether the priority is fast writes and consistency or fast reporting and trend analysis.
Explain the difference between OLTP and OLAP database designs. You should compare their goals, schema design, query patterns, and performance characteristics, and describe when you would use each. If helpful, relate your answer to operational application databases versus reporting models such as a star schema used in platforms like Infosys Cobalt Data & Analytics.
A strong medium-level answer should go beyond definitions. You should discuss normalized transactional models versus analytical fact/dimension models, the kinds of SQL each supports, and the trade-offs around concurrency, aggregation, and update frequency.