The short answer is “yes.” The need to focus on business process measurement events, plus grain, dimensions and facts, is as important as ever. When dimensional modeling was popularized several decades ago, we concentrated on schema designs that delivered query performance and ease-of-use. But as I described in Design Tip #160 Think Dimensionally (Beyond Data […]
Dimensional Modeling Fundamentals
Design Tip #43 Dealing with Nulls in the Dimensional Model describes two cases where null values should be avoided in a dimensional model; in these situations, we recommend using default values rather than nulls. This Design Tip provides guidance for selecting meaningful, verbose defaults. Handling Null Foreign Keys in Fact Tables The first scenario where […]
Industry-standard data models are an appealing concept at first blush, but they aren’t the time savers they are cracked up to be. What’s more, these prebuilt models may inhibit data warehouse project success. Vendors and proponents argue that standard, prebuilt models allow for more rapid, less risky implementations by reducing the scope of the data […]
A student attending one of Kimball Group’s recent onsite dimensional modeling classes asked me for a list of “Kimball’s Commandments” for dimensional modeling. We’ll refrain from using religious terminology, but let’s just say the following are not-to-be-broken rules together with less stringent rule-of-thumb recommendations. Rule #1: Load detailed atomic data into dimensional structures. Dimensional models […]
Delivering consistent data is like reaching the top of Mount Everest for most data warehouse initiatives, and data stewards are the climbers who fearlessly strive toward that goal. Achieving data consistency is a critical objective for most DW/BI programs. Establishing responsibility for data quality and integrity can be extremely difficult in many organizations. Most operational systems effectively capture key […]
Do you know the difference between dimensional modeling truth and fiction? According to Merriam-Webster, fables are fictitious statements. Unfortunately, fables about dimensional modeling circulate throughout our industry. These false claims and assertions are a distraction, especially if you’re trying to align a team. In this column, we’ll describe the root misunderstandings that perpetuate these myths so […]