File Name: facts and dimensions in data warehousing .zip
Citation details: Arifin,S. An online analytical processing multi-dimensional data warehouse for malaria data. Database Vol.
Difference Between Fact Table and Dimension Table
Join Stack Overflow to learn, share knowledge, and build your career. Connect and share knowledge within a single location that is structured and easy to search. When reading a book for business objects, I came across the term- fact table and dimension table. That is because the 2 types of tables are created for different reasons. However, from a database design perspective, a dimension table could have a parent table as the case with the fact table which always has a dimension table or more as a parent. Also, fact tables may be aggregated, whereas Dimension tables are not aggregated. Another reason is that fact tables are not supposed to be updated in place whereas Dimension tables could be updated in place in some cases.
A fact table is used in the dimensional model in data warehouse design. A fact table consists of facts of a particular business process e. Facts are also known as measurements or metrics. A fact table record captures a measurement or a metric. This schema is known as the star schema. ZenTut Programming Made Easy.
Dimension (data warehouse)
A fact table is a primary table in a dimensional model. They are joined to fact table via a foreign key. Dimension tables are de-normalized tables. Fact table is located at the center of a star or snowflake schema, whereas the Dimension table is located at the edges of the star or snowflake schema. Fact table is defined by their grain or its most atomic level whereas Dimension table should be wordy, descriptive, complete, and quality assured. Fact table helps to store report labels whereas Dimension table contains detailed data. Fact table does not contain a hierarchy whereas the Dimension table contains hierarchies.
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A dimension is a structure that categorizes facts and measures in order to enable users to answer business questions. Commonly used dimensions are people, products, place and time. In a data warehouse , dimensions provide structured labeling information to otherwise unordered numeric measures. The dimension is a data set composed of individual, non-overlapping data elements. The primary functions of dimensions are threefold: to provide filtering, grouping and labelling. These functions are often described as "slice and dice". A common data warehouse example involves sales as the measure, with customer and product as dimensions.
Dimension tables contain the descriptive attributes used by BI applications for filtering and grouping the facts. With the grain of a fact table firmly in mind, all the.
Facts and dimensions
This chapter explains how to create a logical design for a data warehousing environment and includes the following topics:. Your organization has decided to build a data warehouse. You have defined the business requirements and agreed upon the scope of your application, and created a conceptual design. Now you need to translate your requirements into a system deliverable. To do so, you create the logical and physical design for the data warehouse.