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Track SQL Performance & Data Modeling

Dimension and Fact Tables

7 / 9

SQL Performance & Data Modeling

Course Progress0/9

Query Efficiency Basics

Efficient SELECT Statements Filtering Early

Understanding Indexes

Index Concepts Query Analysis with EXPLAIN

Data Modeling Fundamentals

Normalization vs Denormalization Foreign Keys and Relationships

Star Schema Patterns

Dimension and Fact Tables Time Dimension Patterns

Capstone Project

Capstone: Analytics Dashboard Design

SQL

Understanding Star Schema

Star Schema

The Pattern

Fact Table (center):

Contains measurable data (events, transactions)
Foreign keys to dimensions
Example: events (event_id, user_id, session_id, event_type, event_time)

Dimension Tables (points of the star):

Descriptive data about entities
Example: users (id, username, email, tier, region)

Our Dataset as Star Schema

Fact table: events
Dimensions: users, sessions

Your Task

Query the star schema to analyze events by user tier:

Group events by user tier
Show: tier, event_count
Order by event_count descending

query.sql

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