Data Marts vs. Data Warehouses

Improved Access to Business Data Can be Achieved in Different Ways

Nov 4, 2009

The term 'data warehousing' can be applied to a broad range of approaches for providing improved access to business decision support data, based on customer transactions.

These approaches can range from the simple to the more complex, with many variations in between. However, there are two major approaches that differ greatly in scale and complexity: the data mart and the data warehouse.

Defining the Data Mart

A data mart is a subject-oriented or department-oriented data storage facility, and may be viewed as a scaled-down version of a data warehouse, one that focuses on the local needs of a specific department, such as financing, marketing, or manufacturing. A data mart contains a subset of the data that would be stored in an enterprise’s data warehouse, because it stores only data related to a specific department. An enterprise may have many data marts, each focused on a sub-set of the overall data stored in a typical data warehouse.

A data warehouse is an orderly and accessible repository of known facts or data from many subject areas, and it is widely used as a basis for decision-making. In contrast to the data mart approach, the data warehouse is generally enterprise-wide in scope. Its goal is to provide a single, integrated view of all of the data gathered and stored within the enterprise, spanning all of the enterprise’s activities, both customer-related and operational. The data warehouse consolidates data marts and reconciles the various departmental perspectives into a single enterprise perspective.

Advantages and Disadvantages in the Two Data Storage Approaches

An advantage of the data mart is that the cost and effort required to implement it is considerably less than for a data warehouse, because the scope of coverage of the data mart application is usually one subject area, whereas the data warehouse covers multiple subject areas within an enterprise. For this reason, a data mart can often be implemented in one-tenth of the time it would take to build a data warehouse, often in months rather than years. Data marts are often used as stepping stones to a data warehouse.

Differences in Implementation

In terms of the cost differential, data marts can usually be implemented at costs in the tens or hundreds of thousands of dollars, as opposed to the millions of dollars required for a data warehouse implementation.

Since a data warehouse is a cross-functional facility, covering multiple subject areas and serving many more users than a data mart, it is a more complex undertaking and requires many more resources, as well as the establishment of a centralized, structured view to all data in the enterprise.

The copyright of the article Data Marts vs. Data Warehouses in Customer Relations is owned by Duane Sharp. Permission to republish Data Marts vs. Data Warehouses in print or online must be granted by the author in writing.