Data Warehouses (EDW vs DataMarts)

There are two fundamental types of data warehouses:

•  Enterprise Data Warehouses (EDW)

•  Data Marts

Overview of Enterprise Data Warehouse (EDW) and Data Marts

Enterprise Data Warehouse (EDW): The enterprise data warehouse is typically a large organization-wide database repository that crosses over every business function and includes data from every organizational unit, division, and department.  In essence, an enterprise data warehouse is a substantially large repository of historical and current transaction data of an entire organization. As an implementation of an enterprise data warehouse is commonly strategic in nature, the volume of data in enterprise data warehouses tends to be quite large.  Enterprise data warehouses can contain hundreds of gigabytes, terabytes, and sometimes even petabytes of data.

Data Mart: A data mart is a collection of subject areas organized for decision support based on the needs of a given department or office.  Many times, a data mart will serve as the reporting and analytical solution for a particular department within an organization, such as accounting, sales, customer service, and/or marketing.  For the most part, data marts are designed with just enough data entities, fields, and records to satisfy one department’s requirements.

There are two kinds of data marts that exist — dependent and independent:

•  A dependent data mart is one whose source is another data warehouse, and all dependent data marts within an organization are typically fed by the same source — the enterprise data warehouse.

•  An independent data mart is one whose source is directly from transactional systems, legacy applications, or external data feeds.