Data Warehouse Schemas
Create star schema and snowflake schema diagrams for data warehouse documentation. Use ERD tables and auto-layout to visualise fact and dimension tables.
Data warehouse schemas organise data for analytics and reporting. NeoArc Studio supports star schema and snowflake schema diagrams using ERD tables with specialised layouts.
Star Schema
A star schema consists of a central fact table surrounded by dimension tables. The layout resembles a star with the fact table at the centre.
Creating a Star Schema
Snowflake Schema
A snowflake schema normalises dimension tables, creating additional levels of hierarchy. Dimension tables branch out from the fact table like snowflake arms.
Creating a Snowflake Schema
Visual Conventions
Use visual conventions to distinguish table types:
| Table Type | Visual Treatment |
|---|---|
| Fact tables | Darker fill colour, positioned centrally |
| Primary dimensions | Medium colour, connected to fact |
| Secondary dimensions | Lighter colour, connected to primary dimensions |
| Bridge tables | Outline only, positioned between related tables |
Auto-Layout for Data Warehouse
Use NeoArc's auto-layout options:
| Layout | Description |
|---|---|
| ERD Left-to-Right | Places fact table on the left with dimensions flowing right |
| ERD Top-Down | Hierarchical layout showing dimension levels |
| Force-Directed | Organic layout that naturally centres the fact table |
Common Patterns
Best Practices
Consistent Naming
Use naming conventions (Fact*, Dim*).
Document Grain
Document grain in the fact table description.
Show Keys
Show primary and foreign keys clearly.
Colour Code
Use colour coding to distinguish table types.
Label Relationships
Add labels to relationships describing the join.
Export to SVG
Export for inclusion in documentation.