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CHAPTER 16: What are logical data models... > Logical Data Model Explained - Pg. 333

CHAPTER 16 What are logical data models? What does business need? Forget the technology Enter logical The highlighted row in Table 16.1 shows the focus of this chapter, which is the logical data model. Table 16.1 The Logical Data Model is the focus of this chapter Relational `One-pager' on how something works Detailed business solution on how something works Detailed technical solution on how something works Dimensional `One-pager' on what is monitored Detailed business solution on what is monitored Detailed technical solution on what is monitored Subject Area Model (SAM) Logical Data Model Physical Data Model A logical data model (LDM) takes the business need defined on a subject area model down to the next level of a business solution. That is, once you understand at a broad level the scope of an effort and what business people require to solve their problem, the next step is to come up with a solution for them in the form of a LDM. The logical data model is explained, along with a comparison of relational and dimensional mindsets. Then, for relational models, the techniques of normalization and abstraction are discussed. Then we answer Frequently Asked Questions (FAQ) on dimensional modeling, which leads to explaining terms such as conformed dimensions and factless facts. We conclude by explaining how Logical Data Models are supported by Power Designer, and use four exercises to reinforce the lessons for you. Logical Data Model Explained A logical data model (LDM) is a business solution to a business problem. It is how the modeler captures the business requirements without complicating the model with implementation concerns such as software and hardware. 333