Data Warehouse Models


Data Warehouse Models

In a traditional architecture, there are three common data warehouse models: The enterprise warehouse, the data mart and the virtual warehouse.

1. Virtual warehouse: A virtual warehouse is a set of views over operational databases. For efficient query processing, only some of the possible summary views may be materialized. A virtual warehouse is easy to build but requires excess capacity on operational database servers.

• A virtual data warehouse is a set of separate databases, which can be queried together, so a user can effectively access all the data as if it was stored in one data warehouse.

Data mart: A data mart model is used for business-line specific reporting and analysis. In this data warehouse model, data is aggregated from a range of source systems relevant to a specific business area, such as sales or finance.

• A data mart is a lower-cost, scaled-down version of a data warehouse, usually designed to support a small group of users.

• Data mart offer a targeted and less costly method of gaining the advantages associated with data warehousing and can be scaled up to a full DW environment over time.

• Depending on the source of data, data marts can be categorized as independent or dependent. Independent data marts are sourced from data captured from one or more operational systems or external information providers or from data generated locally within a particular department or geographic area.

• Dependent data marts are sourced directly from enterprise data warehouses.

3. Enterprise warehouse: An enterprise warehouse collects all of the information about subjects spanning the entire organization.

• An enterprise data warehouse model prescribes that the data warehouse contains aggregated data that spans the entire organization. This model sees the data warehouse as the heart of the enterprise's information system, with integrated data from all business units,

• It provides corporate-wide data integration, usually from one or more operational systems or external information providers and is cross-functional in scope.

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