Star Schema Vs Fact Constellation

Hi, today I an informative blog on what a Schema is and the difference between a Star Schema and a Fact Constellation.

Once again I was attending a training session on Business Intelligence and Analytics and this session happened to be on Dimensional Modelling.  The following are a few interesting topics that were covered

Data Warehouse
A relational database structure is one that supports Online Analytical Processing. It acts as a Central Repository for all data from various sources. Here the data is de-normalized and because of this it speeds up the retrieval process of read-oriented data.

Data Mart

Data Marts on the other hand mainly focus on storing data related to a single business unit, vertical or process.

Schema

A logical description of an entire database that includes the name and description of records of all record-types including all associated data items and aggregates.

The question then arises

Star Schema Vs Fact Constellation

First What is a Star Schema?
The simplest style of data mart schema and the most commonly used approach when it comes to developing data warehouses and data marts.

This Schema consists of a fact table referencing several dimensions.

Fact Constellation

Consists of many fact tables connected to several dimensions.

The difference….?

Not very big. The Fact Constellation happens to be a complex version of the Star Schema.

The only major difference between the two is in terms of use. Sophisticated application would most likely use Fact Constellations where as simpler applications would use Star Schema.


That’s all for now folks, and don’t for get to Keep It Real until next time!

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