Concept of Data Warehouse

With the intensification of market competition and the development of the information society, extract (search, query, etc.) from a large amount of data)
It becomes more and more important to develop market strategies. This requirement requires both online services and a large number of applications.
But traditional database systems cannot meet this requirement. It is embodied in three aspects:
The historical data volume is large.

Auxiliary Decision-Making Information involves data from many departments, which is difficult to integrate with data from different systems.

Due to insufficient data access capabilities, its access performance to a large amount of data is significantly reduced.

With the maturity of C/S technology and the development of parallel databases, the development trend of information processing technology is from a large number
The transaction database extracts data and clears and converts it to a new storage format, that is, the data is
Aggregation in a special format. With the development and improvement of this process, such special data that supports decision-making
Storage is called Data Warehouse (DW ).
W. H. Inmon defines data warehouse as a topic-oriented and integrated data warehouse that supports management decision-making processes.
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A topic is the standard for data classification. Each topic corresponds to an objective analysis field, such as a customer or store.
Assists decision-making in integrating a large amount of data from different departments and systems. The data warehouse contains a large amount of historical data.
The data that enters the Data Warehouse is rarely updated. Data in a data warehouse can be divided into 5 to 10 years.
Used for time trend analysis. The data volume of a data warehouse is large, generally about 10 Gb. It is a general database
(100 MB) the data volume is 100 times, and the size of a large data warehouse reaches TB.
Data Warehouse is mainly used in two aspects:
Use the browser analysis tool to find useful information in DW.

The data warehouse system supports DW applications to form a Decision Support System (DSS ).