Data WarehouseData warehouse is subject Oriented, Integrated, Time-Variant and nonvolatile collection of data that support of management's decision making process. Let's explore this Definition of data warehouse.
- Subject Oriented - The Data warehouse is subject oriented because it provide us the information around a subject rather the organization's ongoing operations. These subjects can be product, customers, suppliers, sales, revenue etc. The data warehouse does not focus on the ongoing operations rather it focuses on modelling and analysis of data for decision making.
- Integrated - Data Warehouse is constructed by integration of data from heterogeneous sources such as relational databases, flat files etc. This integration enhance the effective analysis of data.
- Time-Variant - The Data in Data Warehouse is identified with a particular time period. The data in data warehouse provide information from historical point of view.
- Non Volatile - Non volatile means that the previous data is not removed when new data is added to it. The data warehouse is kept separate from the operational database therefore frequent changes in operational database is not reflected in data warehouse.
- Metadata - Metadata is simply defined as data about data. The data that are used to represent other data is known as metadata. For example the index of a book serve as metadata for the contents in the book.In other words we can say that metadata is the summarized data that lead us to the detailed data.
- Metadata is a road map to data warehouse.
- Metadata in data warehouse define the warehouse objects.
- The metadata act as a directory.This directory helps the decision support system to locate the contents of data warehouse.