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The data held in a data warehouse is described as being subject-oriented, integrated, time-variant, and non-volatile (Inmon, 1993).
•Subject-oriented as the warehouse is organized around the major subjects of the organization (such as customers, products, and sales) rather than the major application areas (such as customer invoicing, stock control, and product sales). This is reflected in the need to store decision-support data rather than application-oriented data.
•Integrated because of the coming together of source data from different organization-wide applications systems. The source data is often inconsistent using for example, different data types and/or formats. The integrated data source must be made consistent to present a unified view of the data to the users.
•Time-variant because data in the warehouse 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 as the data is not updated in real-time but is refreshed from operational systems on a regular basis. New data is always added as a supplement to the database, rather than a replacement. The database continually absorbs this new data, incrementally integrating it with the previous data.
kalvinspartan answered the question on July 4, 2018 at 16:35
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