Data Modelling · Data Engineering
Star Schema & SCD Type 2 How data engineers store history
She moves from Pune to Bangalore. Do you overwrite her city or keep the history? Then answer: where did she live when she placed this order?
Reports don't run on the database the app uses. They run on a warehouse, and how that warehouse is modelled decides which questions it can answer. In this live masterclass we model a food-delivery warehouse and build it in SQL: what one row means, facts and dimensions (fact_orders, dim_customer, dim_restaurant, dim_date), star vs snowflake schemas, surrogate keys, and SCD Type 1 vs Type 2, built live. Modelling sits under every Cohort 4 project. It was Module 01, which is in the recordings, so you can join the cohort now and catch up.
Agenda
What we'll cover
- Why companies keep two databases: the one the app runs on, and the warehouse reports run on
- Grain: deciding what one row means before building anything
- Facts and dimensions on a real example: fact_orders, dim_customer, dim_restaurant, dim_date
- Star schema vs snowflake schema, and when each one is used
- Surrogate keys, and why the app's own ID isn't enough
- SCD Type 1 vs Type 2, built live in SQL: a customer moves from Pune to Bangalore
- The modelling questions every data engineering interview asks
Perfect for
Who it's for
Every attendee
What you get
- Live, hands-on session on Zoom
- Live Q&A with the instructor
- Session notes & key resources — emailed after
- Optional: that session's recording + resources — add for ₹99
Your host
Durgesh Yadav
Senior Data Engineer at 7-Eleven · Founder, PrepNPlaced
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Free forever · Saturday 31 October · 12:30 PM IST
Free live seat
Saturday · 12:30 PM IST