Talk to Anup: Ralph Kimball Data warehouse model

Talk to Anup: Ralph Kimball Data warehouse model: Ralph Kimball Data warehouse model and Development approach Ralph Kimball is well known author who introduced new pattern of data stor...

Ralph Kimball Data warehouse model

Ralph Kimball Data warehouse model and Development approach

Ralph Kimball is well known author who introduced new pattern of data storage in Data Warehouse, so called Dimensional Data Architecture; Based on Fact and Dimension tables.

Kimball’s model is much more refined and simplified, where all Subject oriented data you can store in Dimensions, and measures In fact tables; whereas all dimension tables will be connected to fact tables by foreign key relation.

Ralph Kimball introduced Star and Snowflake Schema, to store data in Data Marts/ Data Warehouse.

Implementing this model is very easy and time saving. But Kimball’s model mostly suitable for small and mid-cap industries like Automobile, Education, and Retail.

Here is I have tried to Design Kimball’s DW model

Ralph Kimball’s Model follows Bottom to Top approach, that is nothing but lowest level of detailed data is stored in Data Marts. That is the reason this approach is called Bottom Up approach.

Here Subject Oriented data is stored in Dimension tables and Measures of same data will be stored in Fact tables. 

Take an Example of Students Enrollments, Students Information and Enrollment information; will be stored in Dimension tables whereas number of Students enrolled per class, per Year, percentage will be stored in Fact tables; And dimension tables will be connected to fact table by foreign key relation.

To normalize data at maximum level Kimball introduced Snowflake Schema. One dimension is further subdivided into another dimension, connected with foreign key.

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Difference between Bill Inmon and Ralph Kimball Data warehouse model

Difference between Bill Inmon and Ralph Kimball Data warehouse model

Bill Inmon is first author to introduce Data warehouse design and Kimball has introduced new, relatively simpler Dimensional model design, with Star and snowflake schema.

Here are some differences between Inmon and Kimball’s model.

Bill Inmon Model	Ralph Kimball Model
Inmon Model is little complex to design, and can have lot of customization based on your own style.	Kimball Model relatively easier to develop, time saving and fixed Star or Snowflake schema designs we can use.
Supports Huge industry needs.	Perfectly matches to medium and small company needs.
Time talking and long projects.	Comparatively less time taking.
Require Expertise engineers thought project.	Once developed, little experienced engineers can work.
Design Supports Enterprise applications and wide range of data.	Design supports individual and medium cap clients business area.
After development modification and customization is easier and can be done faster.	After Development modification and customization is time taking process.
Inmon Design uses ER model in Data warehouse.	Kimball Model uses Star and Snowflake Schema.
In Inmon’s design Data Marts are physically separated from Data warehouse.	Whereas in Kimball’s model it’s not necessary to separate Data marts from Dimensional Data warehouse.
Inmon Design suggests First developing Central repository and then developing Data marts from Central repository.	Whereas Kimball’s design suggest developing first critical Data Mart’s which can supports all reporting and analytical needs.

Please leave your comments, suggestions.  

Thank you!