The configuration management database is a virtual concept and is made up of many physical databases and physical stores of information. It becomes a CMDB, when the information is brought together with a common interface that makes the information accessible and relevant for decision makers; most importantly, the CIs are related (linked) to one another.
Too many organizations take a technical view of the CMDB and begin by trying to develop a database schema so they can build one. It is important to emphasize again, that the CMDB is not one physical database. It is a logical concept for organizing information, whose closest tangible representation may be a common interface with many collections of information. It is made up of many physical databases, at least one of which will contain the relationships or links between CIs.
One thing that makes a CMDB unique from most data stores is that it focuses on relationships
between CIs. That is, it allows decision makers to draw visuals of systems and their interconnections so that they can model the potential impacts of a change to any component or collection of components.
Every discipline that is required to understand the workings of complex systems ends up building models of those systems. These models serve to increase basic understanding and also to predict outcomes of changes to the system. As IT environments continue to grow in size and complexity, successful managers will be those who are able to model their environments and accurately predict the effects of change.