The Data Warehouse Toolkit: The Definitive Guide to Dimensional Modeling
Ralph Kimball, Margy Ross
Format: PDF / Kindle (mobi) / ePub
Updated new edition of Ralph Kimball's groundbreaking book on dimensional modeling for data warehousing and business intelligence!
The first edition of Ralph Kimball's The Data Warehouse Toolkit introduced the industry to dimensional modeling, and now his books are considered the most authoritative guides in this space. This new third edition is a complete library of updated dimensional modeling techniques, the most comprehensive collection ever. It covers new and enhanced star schema dimensional modeling patterns, adds two new chapters on ETL techniques, includes new and expanded business matrices for 12 case studies, and more.
- Authored by Ralph Kimball and Margy Ross, known worldwide as educators, consultants, and influential thought leaders in data warehousing and business intelligence
- Begins with fundamental design recommendations and progresses through increasingly complex scenarios
- Presents unique modeling techniques for business applications such as inventory management, procurement, invoicing, accounting, customer relationship management, big data analytics, and more
- Draws real-world case studies from a variety of industries, including retail sales, financial services, telecommunications, education, health care, insurance, e-commerce, and more
Design dimensional databases that are easy to understand and provide fast query response with The Data Warehouse Toolkit: The Definitive Guide to Dimensional Modeling, 3rd Edition.
rolled-up summary grains are important for performance tuning, but they pre-suppose the business’s common questions. Each proposed fact table grain results in a separate physical table; different grains must not be mixed in the same fact table. Chapter 1 DW/BI and Dimensional Modeling Primer, p 30 Chapter 3 Retail Sales, p 71 Chapter 4 Inventory, p 112 Chapter 6 Order Management, p 184 Chapter 11 Telecommunications, p 300 Chapter 12 Transportation, p 312 Chapter 18 Dimensional Modeling Process
team to integrate data from multiple operational source systems, even if they lack consistent source keys by using a back room cross-reference mapping table to link the multiple natural keys to a common surrogate. ■ Improve performance. The surrogate key is as small an integer as possible while ensuring it will comfortably accommodate the future anticipated cardinality (number of rows in the dimension). Often the operational code is a bulky alphanumeric character string or even a group of ﬁelds.
Warehouse Key (FK) Inventory Transaction Type Key (FK) Inventory Transaction Number (DD) Inventory Transaction Dollar Amount Product Dimension Inventory Transaction Type Dimension Inventory Transaction Type Key (PK) Inventory Transaction Type Description Inventory Transaction Type Group Figure 4-4: Warehouse inventory transaction model. Even though the transaction fact table is simple, it contains detailed information that mirrors individual inventory manipulations. The transaction fact table
each function’s requirements, the matrix cells are shaded to indicate which business functions are interested in 128 Chapter 4 which business processes (and projects), as illustrated in Figure 4-11’s opportunity/ stakeholder matrix variation. It also identiﬁes which groups need to be invited to the detailed requirements, dimensional modeling, and BI application speciﬁcation parties after a process-centric row is queued up as a project. Finan ce L o gis tics ions Oper at X X X X
is updated in the absence of a sales transaction. If the business requires accurate point-in-time proﬁling, a supplemental factless fact table with effective and expiration dates can capture every relationship change between the customer and demographics dimensions. Hybrid Slowly Changing Dimension Techniques In this ﬁnal section, we’ll discuss hybrid approaches that combine the basic SCD techniques. Designers sometimes become enamored with these hybrids because they seem to provide the best of