Warehouse Mechanism - Star Schema And Extended Star Schema
Star Schema: In data warehousing and business intelligence (BI), a star schema is the simplest form of a dimensional model, in which data is organized into facts and dimensions. A fact is an event that is counted or measured, such as a sale or login. A dimension contains reference information about the fact, such as date, product, or customer. A star schema is diagrammed by surrounding each fact with its associated dimensions. The resulting diagram resembles a star. Star sctrial are optimized for querying large data sets and are used in data warehouses and data marts to support OLAP cubes, business intelligence and analytic applications, and ad-hoc queries. Within the data warehouse or data mart, a dimension table is associated with a fact table by using a foreign key relationship. The dimension table has a single primary key that uniquely identifies each member record (row). The fact table contains the primary key of each associated dimension table as a foreign key. Combine...