Conformed Dimensions & Enterprise Integration

Overview

A dimensional model becomes an enterprise data warehouse when dimensions are shared (conformed) across multiple fact tables, enabling consistent drill-across queries. Without conformed dimensions, each fact table becomes an isolated silo — users cannot compare sales with inventory with marketing in a single report.

Key Principle: Conformed dimensions are built once, used everywhere. They must have identical column names, data types, and domain values across all fact tables that reference them.

Anti-Pattern: Never join fact tables directly to each other. Instead, use conformed dimensions to "drill across" from one fact to another.

When to Use This Skill

• Planning which dimensions will be shared across multiple fact tables
• Building an enterprise data warehouse bus matrix
• Designing shrunken (rollup) dimensions for aggregate fact tables
• Enabling cross-process analytics (e.g., comparing sales with returns with inventory)
• Reviewing a dimensional model for consistency before ERD creation

The Bus Matrix