The Data. Warehouse. Toolkit. Third Edition. Ralph Kimball. Margy Ross. The Definitive Guide to. Dimensional Modeling. Ralph Kimball. Margy Ross. The Data Warehouse. Toolkit. Second Edition .. a lightning tour of The Data Warehouse Lifecycle Toolkit (Wiley. The Data Warehouse Lifecycle Toolkit. Table of Contents appendix to the full treatment of this subject in Ralph Kimball's earlier book, The Data. Warehouse.
|Language:||English, Spanish, Japanese|
|Distribution:||Free* [*Register to download]|
This books (The Data Warehouse Lifecycle Toolkit [PDF]) Made by Ralph Kimball About Books A thorough update to the industry standard for. This chapter is a lightning tour of The Data Warehouse Lifecycle Toolkit, . the ﬁrst edition of The Data Warehouse Toolkit (Wiley, ), Ralph Kimball devoted . The Data Warehouse. Lifecycle Toolkit. Second Edition. Ralph Kimball. Margy Ross. Warren Thornthwaite. Joy Mund v. Bob Becker. 1 в О 7. * WILEY. 2 О О 7.
The fact table has all the measures that are relevant to the subject area, and it also has the foreign keys from the different dimensions that surround the fact. The dimensions are denormalized completely so that the user can drill up and drill down without joining to another table. Multiple star schemas will be built to satisfy different reporting requirements.
So, how is integration achieved in the dimensional model? The key dimensions, like customer and product, that are shared across the different facts will be built once and be used by all the facts Kimball et al. This ensures that one thing or concept is used the same way across the facts.
This is the document where the different facts are listed vertically and the conformed dimensions are listed horizontally. Where ever the dimensions play a foreign key role in the fact, it is marked in the document. This serves as an anchoring document showing how the star schemas are built and what is left to build in the data warehouse.
The star schema can be easily understood by the business users and is easy to use for reporting. Most BI tools work well with star schema. The foot print of the data warehousing environment is small;it occupies less space in the database and it makes the management of the system fairly easier. The performance of the star schema model is very good.
This is known to be a very effective database operation.
A small team of developers and architects is enough to keep the data warehouse performing effectively Breslin, Works really well for department-wise metrics and KPI tracking, as the data marts are geared towards department-wise or business process-wise reporting.
Drill-across, where a BI tool goes across multiple star schemas to generate a report can be successfully accomplished using conformed dimensions. Redundant data can cause data update anomalies over time. Adding columns to the fact table can cause performance issues. This is because the fact tables are designed to be very deep.
If new columns are to be added, the size of the fact table becomes much larger and will not perform well. This makes the dimensional model hard to change as the business requirements change. Cannot handle all the enterprise reporting needs because the model is oriented towards business processes rather than the enterprise as a whole.
Integration of legacy data into the data warehouse can be a complex process. Deciding Factors Now that we have seen the pros and cons of the Kimball and Inmon approaches, a question arises.
Which approach should be used when? This question is faced by data warehouse architects every time they start building a data warehouse. Here are the deciding factors that can help an architect choose between the two: Reporting Requirements — If the reporting requirements are strategic and enterprise-wide and integrated reporting is needed, then Inmon works best.
Project Urgency — If the organization has enough time to wait for the first delivery of the data warehouse say 4 to 9 months , then Inmon approach can be followed.
If there is very little time for the data warehouse to be up and running say, 2 to 3 months then the Kimball approach is best Breslin, Future Staffing Plan — If the company can afford to have a large sized team of specialists to maintain the data warehouse, then the Inmon method can be pursued. If the future plan for the team is to be thin, then Kimball is more suited. Frequency of Changes — If the reporting requirements are expected to change more rapidly and the source systems are known to be volatile, then the Inmon approach works better, as it is more flexible.
If the requirements and source systems are relatively stable, the Kimball method can be used. Organization Culture — If the sponsors of the data warehouse and the managers of the firm understand the value proposition of the data warehouse and are willing to accept long-lasting value from the data warehouse investment, the Inmon approach is better.
If the sponsors do not care about the concepts but want a solution to get better at reporting, then the Kimball approach is enough. Conclusion It has been proven that both the Inmon and Kimball approach work for successfully delivering data warehouses. In a hybrid model, the data warehouse is built using the Inmon model, and on top of the integrated data warehouse, the business process oriented data marts are built using the star schema for reporting.
We cannot generalize and say that one approach is better than the other; they both have their advantages and disadvantages, and they both work fine in different scenarios. The architect has to select an approach for the data warehouse depending on the different factors; a few key ones were identified in this paper. References Breslin, Mary. Accessed May 22, Inmon, W.
Building the Data Warehouse, Fourth Edition. Marakas, George M. Prentice Hall, You ll learn to create adaptable systems that deliver data and analyses to business users so they can make better business decisions.
To Download Please Click https: SlideShare Explore Search You. Submit Search. Successfully reported this slideshow. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads.
You can change your ad preferences anytime. Upcoming SlideShare. Like this presentation? Why not share!
An annual anal Embed Size px. Start on. Show related SlideShares at end. WordPress Shortcode. Published in: Full Name Comment goes here. Are you sure you want to Yes No. Be the first to like this. No Downloads. Views Total views. Actions Shares. Embeds 0 No embeds.