1. Data Warehousing : Data Warehousing is a technique that gathers or collects data from different sources into a central repository, or, in other words, a single, complete, and consistent store of data that is obtained from different sources. It is a powerful database model that enhances the user ability to analyze huge, multidimensional datasets; allowing the user to make a business decision based on facts, for tracking quick and effective decisions, or providing necessary information.
Difference between Data Warehousing and Online-Transaction processing (OLTP) :
Data Warehousing DWH | Online transaction |
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It is technique that gathers or collect data from different sources into central repository. | It is technique that is used for detailed day to day transaction data which keep chaining on everyday. |
It is designed for decision making process. | It is designed for business transaction process. |
It stores large amount of data or historical data. | It holds current data. |
It used for analyzing the business. | It used for running the business. |
In Data warehousing, the size of database is around 100GB-2TB . | In Online transaction processing, the size of data base is around 10MB-100GB. |
In Data warehousing, denormalized data is present. | In Online transaction processing, normalized data is present. |
It uses Query processing. | It uses transaction processing |
It is subject-oriented. | It is application-oriented. |
In Data warehousing, data redundancy is present. | In Online transaction processing, there is no data redundancy. |