Foreword A data model is the brain of an application, a conceptual framework that represents the business as accurately as possible. It defines the players, actions, and rules that govern the ways in which business processes work, representing them in a standard syntax that both humans and applications can interpret. In essence, a data model turns business concepts into computer code so that applications and systems can process information on our behalf. Without data models, we wouldn't be able to automate many of the processes that drive our organizations. Given the pivotal role played by data models, it should be no surprise that they often determine whether an application is effective. A poorly designed data model can wreak havoc on even the most elegantly designed application. Poor performance, inaccurate query results, inflexible rules, and inconsistent metadata are just some of the results of a poor data model. A poor data model can hamstring an application.