Ravindra BagaleCourses & study guides

11. Data Modelling

11.8 Modelling Best Practices

  1. Use a star schema: facts in the centre, dimensions around.
  2. Use one-to-many, single-direction relationships wherever possible.
  3. Always build a dedicated, marked date table and turn off Auto date/time.
  4. Hide foreign keys in the fact table (users should filter using the dimension columns).
  5. Remove unused columns and rows in Power Query – smaller model, faster report.
  6. Use integer keys and correct data types; avoid high-cardinality text keys where possible.
  7. Prefer measures over calculated columns for aggregations.
  8. Give tables and columns business-friendly names (Customer Name, not cust_nm).
  9. Set Summarize by = None for numeric attributes like Year and IDs.
  10. Keep a consistent number format and put measures in display folders with descriptions.

Mini-exercise

Load the Blinkit tables. Build the star schema (रचना), create the DAX date table above, mark it as a date table, set Month Name to sort by Month Number, create the inactive Delivered Date relationship, and hide all ID columns in Orders.

Ravindra Bagale's Tip

Friends, many students let Autodetect relationships create links on columns with similar names, like "ID" to "ID". Turn it off for new projects (File › Options › Data Load) and create each relationship deliberately. Review Model view after every new table. Clear?

Thodkyaat sangaycha tar (quick recap)

Star schema vapra, relationships single direction theva, Date table continuous theva aani Mark as date table karayla visru naka. Samjla ka? He concepts pudhe pratyek module madhe lagtil. Aata pudhe jaauya hierarchies aani groups kade.