- Data warehousing is subject-oriented, integrated, time-variant, and non-volatile collection of data in support of management’s decision-making process.
- A data warehouse is data management and data analysis.
- Data webhouse is a distributed data warehouse that is implement over the web with no central data repository.
- Goal is to integrate enterprise wide corporate data into a single repository from which users can easily run queries.
EXPLANATION :
Subject-oriented: WH is organized around the major subjects of the enterprise..rather than the major application areas.. This is reflected in the need to store decision-support data rather than application-oriented data.
Integrated: Because the source data come together from different enterprise-wide applications systems. The source data is often inconsistent using..The integrated data source must be made consistent to present a unified view of the data to the users.
Time-variant: The source data in the WH is only accurate and valid at some point in time or over some time interval. The time-variance of the data warehouse is also shown in the extended time that the data is held, the implicit or explicit association of time with all data, and the fact that the data represents a series of snapshots.
Non-volatile: Data is not update in real time but is refresh from OS on a regular basis. New data is always added as a supplement to DB, rather than replacement. The DB continually absorbs this new data, incrementally integrating it with previous data.
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