Semantic & Metrics Layer
Finance and growth report different revenue for the same month, because each team rebuilt “the” customer table its own way. Modeling is not academic — it is why your numbers do or don't reconcile.
This stratum covers dimensional modeling end to end: star schemas and the Kimball bus matrix, slowly changing dimensions (SCD Type 1 and 2), Data Vault 2.0, One Big Table and wide-table designs, conformed dimensions, and how to choose a modeling style for a real warehouse.
What you'll learn
- Design star schemas, fact and dimension tables, and a conformed bus matrix
- Implement slowly changing dimensions (SCD Type 1 and 2) correctly
- Know when Data Vault 2.0, One Big Table, or classic Kimball fits the problem
- Make different teams' metrics reconcile through conformed dimensions
Tracks & courses
Full navigation is in the sidebar. Here's what each track gives you and the courses inside it.
Dimensional Modeling Foundations
The shared vocabulary every metrics layer assumes — grain, facts, dimensions, SCDs, conformed dimensions, and the bus matrix.
Dimensional Modeling Fundamentals
Grain, facts, dimensions, measures, keys — the engine-agnostic vocabulary every metrics layer assumes. Build the words you'll use for the rest of Strata 7.
11 ch · 2h 37m
2 freeSlowly Changing Dimensions
When a customer changes their region, every historical fact silently lies — unless you've modeled the change. SCD types 1/2/3/6, effective-dating, bitemporal, and the production anti-patterns that bite teams in their first year.
9 ch · 1h 52m
2 freeConformed Dimensions & the Bus Matrix
Kimball's organizational technology: how to keep 'customer' meaning one thing across marketing, finance, and product — and how the bus matrix turns conformance from a Slack-thread into a treaty.
7 ch · 1h 23m
2 freeModeling Alternatives: Data Vault & OBT
When stars aren't the answer. Data Vault for audit-heavy, source-volatile environments; OBT for columnar engines with low-cardinality joins; and how to choose between styles.
Data Vault 2.0
The audit-first, source-volatile-first alternative to Kimball. Hubs, links, satellites, hash keys, and PIT tables — and the honest discussion of when Vault is the right tool versus when it's cosplay.
11 ch · 2h 16m
2 freeOne Big Table & Wide-Table Design
The columnar-engine-native modeling style. When 200-column denormalized tables go from heresy to the right answer — and where OBT's quiet costs (update amplification, fan-out, governance) live.
9 ch · 1h 34m
2 freeChoosing a Modeling Style
The decision framework that spans Kimball, Vault, and OBT. By the end, the choice is defensible — you can name the inputs, predict the costs, and explain why one approach wins for your specific team, sources, engine, and change rate.
7 ch · 1h 9m
2 freeRelated topics
Start Semantic & Metrics Layer free
The first chapters of every course are free to read — no account needed.