Data warehousing is derived from the English word “Data Warehouse” and is also called “DWH“
According to one definition of DWHcreated by Bill Inmon, the “father of data warehousing”,
a DWH is: “A DWH is a system of data warehouses, which are used to store, process, and manage data.
“An enterprise-structured repository of subject-oriented, integrated, time-varying, historical data used for information retrieval and decision support in the enterprise, including both atomic and aggregated data.”
Thus, it is a structured repository of various historical data for analysis and used for decision support in various current and future corporate activities and processes. Storing data and analyzing it provides a means to learn from past mistakes as well as to gain inspiration for the future.
Data Warehouse Features
–Object-oriented(provides information about activities, not ongoing operations)
–Integrity(data from different sources are stored as a single entity)
–Temporal composition (information from the same time period is combined to form data history)
–Persistent storage (data is only added, not deleted, so it is stored permanently)
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Data warehouses are most often created by corporate IT administrators . This is perhaps the most challenging task. There are several methods for its creation. The most commonly used methods are “Big Bang method” and “Incremental method“.
“Big Bang method
The entire plan can be fully worked out before the actual implementation begins. The disadvantage is that it can be complicated or impossible to implement possible changes, both from the user and from the technical side. In addition, creation by this method is quite time consuming. It consists of the following three parts.
2. 2. Creating an enterprise data warehouse
[creating access directly or indirectly
3.]
Data warehouses are most often created by corporate IT administrators . This is perhaps the most challenging task. There are several methods for its creation. The most commonly used methods are “Big Bang method” and “Incremental method“.
Incremental methods
Here, the data warehouse is built in phases to allow for quicker commissioning and user feedback. The method consists of six phases.
Strategy(defining business goals, objectives, and building the data warehouse)
2. Definitions(scope and goals of incremental development, including documentation of data sources)
3. analysis(information on users, access requirements, data quality)
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4. design(putting requirements into concrete design and creating models)
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Build(create and test database structure)
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[production(use the data warehouse and manage its maintenance and growth)
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