Data Warehouse

3.Introduction to DW&BI – Kimball or Inmon Model

Data warehouse – Kimball or Inmon model.

The following information provides an understanding of the basics of two different approach in Data warehouse modeling:

History of Data Warehouse:

In 1990 Inmon wrote a book “Building the Data Warehouse.”

Inmon defines an architecture for the collection of disparate sources into detailed, time variant data store (The top-down approach).

In 1996 Kimball wrote “The Data Warehouse Toolkit.”

Kimball updates the book and defines multiple databases called data-marts that are organized by business processes but use Data bus architecture (The bottom-up approach).


Data Warehouse VS Data Mart:

A Data warehouse is a collection of Enterprise-wide data across the line of business and subject areas. Data is integrated using a massive database. Provides a complete organizational view of the information needed to run the business.

A Data mart offers the departmental view of information specific and subject-oriented. Build multiple data-marts using dimensional architecture. Provides Fact-based information integrated with various dimensions.


Inmon Model:


  • As per Bill Inmon, a data warehouse is a subject-oriented data repository and the data in the database organized with data elements relating and linking together.
  • Time-variant: The changes to the data in the database tracked and recorded showing changes over time.
  • Non-volatile: Data in the database is never over-written or deleted – once committed, the data is static, read-only, but retained for future, and for maintaining the history.
  • Database: The database contains data from all operational applications, and the data is made consistent for reporting purpose.
  • The data warehouse should be designed from the top-down to include all corporate data. In this methodology, data marts created after the complete data warehouse creation.

Kimball Model:


  • Ralph Kimball is the proponent of the dimensional modeling and approach to building data warehouse through data marts.
  • As per Kimball, the data warehouse is nothing more than the union of all the data-marts. Kimball indicates a bottom-up approach for data warehousing, by creating individual data marts are created providing views into the organizational data in chunks
  • Eventually, an Enterprise Data warehouse built by combining the data marts using Bus architecture.

Inmon VS Kimball:


 

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