Who is a Data Engineer?
A Data Engineer designs and maintains systems that collect, transform, and deliver data for analytics and business decisions.
What does a Data Engineer do?
- Builds reliable ETL/ELT pipelines from multiple data sources.
- Prepares clean and structured datasets for analysts and data scientists.
- Designs data warehouse schemas (fact and dimension tables).
- Monitors data quality, freshness, and pipeline failures.
- Optimizes query performance and data processing costs.
What should a Data Engineer know?
- Strong SQL: joins, aggregations, window functions, and query tuning.
- Data modeling: normalization, denormalization, star and snowflake schemas.
- Pipeline orchestration and scheduling principles.
- Batch and streaming concepts, incremental loading, and idempotency.
- Cloud storage, data warehouses, and observability basics.
This page helps you practice interview-style Data Engineering questions on SQLTest.online.