ResiliEnt is your Consulting Services Partner - Your Success is Our Mission! While the data warehousing industry has matured significantly in the last decade, data warehousing methodologies are still rapidly evolving. Arguments continue as to which methodology has reached the status of being ‘widely recognized’. Two of the leading experts are Bill Inmon and Ralph Kimball.
- Bill Inmon has over two decades of database technology management experience and data warehouse design expertise, has published 36 books and more than 350 articles in major computer journals. He is known for his seminars on developing data warehouses and has been a keynote speaker for every major computing association. Before founding Pine Cone Systems, Bill was a co-founder of Prism Solutions, Inc.
- Ralph Kimball is a leading proponent of the dimensional approach to designing large data warehouses. He currently teaches data warehousing design skills to IT groups, and helps selected clients with specific data warehouse designs. Ralph is a columnist for Intelligent Enterprise magazine and has a relationship with Sagent Technology, Inc., a data warehouse tool vendor. His book "The Data Warehouse Toolkit" is widely recognized as the seminal work on the subject.
In “Ask The Experts”, published in DMReview.com on January 25, 2002, when asked about the differences in philosophies between Misters Inmon and Kimball, Clay Rehm is quoted as saying: “The major difference in the philosophies boils down to database design. Inmon favors third normal form design while Kimball favors star schemas (denormalized) design.”
We agree with Mr. Rehm’s opinion and add one of our own: They also differ in what information to include. Inmon advocates pulling all data available, leaving nothing behind. Kimball advocates only pulling the data specified in the business requirements.
While Inmon and Kimball are the leading experts in the data warehousing industry today, they are by no means the only two. There are many others, each with their own methodology. A member of our delivery team found a white paper on the internet that did a comparison of 15 different data warehousing methodologies. With so much to choose from, it’s no wonder that no one methodology has become ‘the one’, leading many organizations to make up one of their own. What is quickly gaining favor in the data warehousing industry is using a ‘blending’ of different methodologies. It allows the flexibility to tailor solutions to the specific needs of the organization.
We also agree with using a ‘blending’ of methodologies, and we call ours The ResiliEnt Hybrid, or the “The Carry Forward” method. Our method pulls all data available (as advocated by Inmon) while using a denormalized design (as advocated by Kimball).
- quickly gaining favor in the data warehousing industry
- allows the flexibility to tailor solutions
‘The Carry Forward’ method
- pulls all data available (as advocated by Inmon)
- uses a denormalized design (as advocated by Kimball)
Important points about the ResiliEnt Data Warehouse:
- The Operational Source Data can be any source data, from operational systems to an Excel spreadsheet.
- The Staging Area is where all the data is brought together, cleansed, transformed, and readied for the Presentation Area (Data Marts). This area is off-limits to end users.
- Both the Staging Area and Presentation Area (Data Marts) contain complete histories of the data. The Staging Area contains the original source information, making reprocessing much simpler. The Presentation Area (Data Mart) contains all conformed records.
- The Presentation Area (Data Marts) is where the organization does its data retrievals.
We like to look at a data warehouse as analogous to a restaurant:
- The Operational Source Data is the pantry or refrigerator, where all the ‘raw food’ (raw data) is originally stored.
- The Staging Area is the kitchen. As with a restaurant, ‘customers’ (end-users) are not allowed in the kitchen.
- The Raw Staging Area is the counter top where you place the ‘raw food’ (raw data) for preparation.
- The Refined Staging Area is where the ‘preparation’ takes place. The ‘meal’ (final cleansed data) to be prepared dictates the ‘amount of work’ (number of refined staging tables) needed. To create your ‘meal’ (final cleansed data), you may simply need a bowl and a spoon; or you may need bowls, pots, pans, and an hours worth of cooking in the oven.
- The Final Staging Area is the plate where you place the ‘meal’ (final cleansed data).
- The Data Mart (aka: Presentation Area) is the dining room. The ‘meal’ (final cleansed data) is carried from the ‘kitchen’ (Staging Area) to the dining room where your ‘customer can enjoy the meal you have prepared' (end-users can query the final cleansed data).