SQL Data Warehouse / ETL Questions

 Very important for BI Architect roles.

Q1: What is SCD Type 1?

Overwrite old data.

Q2: What is SCD Type 2?

Keep history using effective dates.

Q3: How do you perform Incremental Load?

Load only changed records.

Q4: How do you handle late arriving dimensions?

Update dimension after fact load.

Q5: How do you identify changed records?

Timestamp or hash comparison.