Agile Data Warehouse Design: Collaborative Dimensional Modeling, from Whiteboard to Star Schema 42745th Edition

When it comes to dimensional modeling and related data warehouse and business intelligence (DW/BI) topics, until now the "Big Two" authors who provide truly useful books are Ralph Kimball (along with his Kimball Group colleagues) and Christopher Adamson. With the publication of Agile Data Warehouse Design: Collaborative Dimensional Modeling, from Whiteboard to Star Schema (ADWD), Lawrence Corr (along with his co-author Jim Stagnitto) contributes critical new information and techniques to the field - and we now have the "Big Three" dimensional design authors.Why are these my "Big Three" BI/DW authors, and why does Lawrence Corr deserve to join the list? The numerous Kimball Group books and the three Adamson books all provide a useful blend of theoretical and practical information and techniques to guide the DW/BI professional in creating systems that are affordable, maintainable, accurate, and useful to clients. In his new book, Corr fills in a critical missing component: how to effectively engage business and technical personnel in a dialogue to perform agile design where the emphasis is on content, understandability, rigor, and usefulness, instead of on producing reams of documentation. In short, this book is about agile dimensional design including "why" and the all-important "how to" with supporting templates.Though many of the book's topics are previously addressed by other authors, Corr expands upon these and presents a large set of fresh ideas and techniques that are robust and adaptable, while incorporating the concepts of the Agile Manifesto. He provides an emphasis on collaboration and flexibility, not just on theoretic agility, while adapting a method called BEAM* (Business Event Analysis & Modeling) for dimensional design.BEAM* is an agile modeling method that lends itself to rapid, collaborative dimensional design sessions with business and technical participants. BEAM* utilizes a set of diagram types that, taken together, provide a complete design that is understandable by business people and is immediately useful for implementation people. The diagram types are:1. Example Data Table (or BEAM* Table) - Primary diagram type used to capture data stories and describe data requirements through sample data. Supports modeling by example rather than by abstraction, making them useful to all participants in the design activities. Uses sets of short codes to capture and indicate design details.2. Hierarchy Chart - Shows hierarchical relationships among related entities within a dimension. This is a much cleaner and more concise version of the traditional dimensional hierarchy chart.3. Timeline - Concisely captures sequences and durations as an aid to understanding and design.4. Event Matrix - A fresh twist on the classic fact/dimension matrix, with better organization, which provides an accessible overview of multiple star data mart and data warehouse designs.5. Enhanced Star Schema - Traditional star schema diagrams augmented with BEAM* codes to indicate dimensional design aspects that are not supported by traditional modeling tools.These "tools" facilitate design discussions, detailed design work, communication, implementation, and provide concise yet through documentation.In addition to the methodology and diagram types, extensive coverage of the design process and the designs themselves are covered. All of the dimensional modeling basics receive thorough treatment and many of the more challenging dimensional modeling problems receive substantial coverage with mature techniques and solutions drawn from Corr and Stagnitto's extensive consulting work. Examples include several types of hierarchies and hierarchy maps, multiple calendars, time (clock time), and the always exciting Customer and Employee dimensions, among many other design challenges.Agile Data Warehouse Design is an eminently useful book and a long-needed complement to the dimensional modeling literature.

Good step-by-step guide for capturing data warehousing requirements and building dimensional models from these requirements through modelstorming (data modeling plus brainstorming) with business intelligence stakeholders. After explaining the difference between online transaction processing and data warehousing, and explaining high-level aspects of the 7Ws framework and the BEAM agile dimensional modeling method in the introductory chapter, the authors discuss modeling business events, business dimensions (the second longest chapter containing about 12% of the text), business processes, and star schemas, followed by design patterns for "who" and "what" (the longest chapter containing about 13% of the text), "when and where", "how many", and "why" and "how", corresponding to the 7Ws.Unlike some other technical texts, the authors really do walk the reader through the material one step at a time, with no skipping around between topics that many readers complain about elsewhere. Other than the step-by-step aspect of this book, another reason I found this book so well put together are the abundant, well-placed diagrams throughout that greatly add to the material. Although what initially got me interested in this text is the agile process surrounding data warehousing, the chapters on dimensional design patterns for performance, flexibility, and usability compliment well the book that I currently consider the best on the traditional data warehouse star schema, "Star Schema: The Complete Reference" by Christopher Adamson (see my review).In the chapter covering "who" and "what" design patterns, for example, the authors cover customer dimensions (particularly challenging because of their typical depth, width, and volatility) alongside the mini-dimension pattern, the sensible snowflaking pattern, swappable dimension patterns, customer relationships, and hierarchy maps, as well as employee dimensions alongside the hybrid slowly changing dimension (SCD) view pattern, the previous value attribute pattern, and the multi-valued hierarchy map pattern, followed by product and service dimensions alongside the multi-level dimension pattern and the parts explosion hierarchy map pattern. And the chapter covering "how" design patterns provides one of the best concise explanations of fact table types and fact types.The one potential issue with this book is that although its goal is agile data warehouse design, getting familiar with the BEAM (business event analysis and modeling) notation used throughout the author discussions might be a bit time prohibitive for teams comprised of more than a few individuals to become accustomed when using for the first time. While the second appendix at the back of the book provides effective short codes for event story and fact table types, dimension table types, general column codes, data types, key types, dimensional attribute types, and event detail and fact column types, some upfront initial team investment will almost certainly be involved for which an agile spike will be needed, and close attention to workability with stakeholders should be assessed. Well recommended overall.

I admit that I was a bit jaded about the true effectiveness of Agile and EDW (after all everyone seems to be jumping on the Agile bandwagon and using it as a buzzword). However, after reading this book, I now do see how Agile and EDW could work. It is not a silver bullet for eliminating re-coding or designing a data warehouse that will cover all future reporting needs but it should help in developing a robust, proactive design that anticipates future demand and designs for it.The BEAM* methodology alone was worth the "price of admission". It provides a manner to solicit and capture requirements (using Agile approaches of course) that makes is easier for stakeholders (people who will run and request reports) to articulate requirements. And then, a manner to translate them into Dimensional Models.

Good book overall, obviously not a page turner.I thought this book was a little too vague for me, but really gave me a nice overview of the process and hopeful end result. While the book was easy to follow, the design choices used in it were a little old-fashioned and seemed to make it look like a cheap at-home printed textbook.