The concept of a data warehouse is to have a centralized database that
is used to capture information from different parts of the business process. The definition of a data warehouse can be determined by the collection of data and how it is used by the company and individuals that it supports. Data warehousing is the method used by businesses where they can create and maintain information for a company wide view of the data.
Data Warehouses became a distinct type of computer database during the late 1980s and early 1990s. Data warehouse evolved because demands could not be met with current operational systems. Ultimately, the need caused separate databases to be created that were designed to support decision-making information for departments or management. With this need, the development between operational and informational systems was produced.
The need has been established for a company wide view of data in operational systems. Date warehouses are designed to help management and businesses analyze data and this helps to fill the need for subject- oriented concepts. Integration is closely related to subject orientation. Data warehouses must put data from disparate sources into a consistent format. They must resolve such problems as naming conflicts and inconsistencies among units of measure. When this concept is achieved, the data warehouse is considered to be integrated.
The form of the stored data has nothing to do with whether something is a data warehouse. A data warehouse can be normalized or de-normalized. It can be a relational database, multidimensional database, flat file, hierarchical database, object database, etc. Data warehouse data often gets changed. Also, data warehouses will most often be directed to a specific action or entity.
Data warehouse success cannot be guaranteed for each project. The techniques involved can become quite complicated and erroneous data can also cause errors and failure. When management support is strong, resources committed for business values, and an enterprise vision is established, the end results may turn out to be more helpful for the organization or business. The main factors that create needs for data warehousing for most businesses today are requirements for the companywide view of quality information and departments separating informational from operational systems for improved performance for managing data.