The CMDB provides a unique overview of how the infrastructure is interrelated and the way in which the different items in the infrastructure depend on each other.
The CMDB also contains services and service catalog, preferably with relationships to other items, to see which supporting configuration items (CI) the services are dependent on.
The CMDB contains mainly 4 things:

• Items (this may be services, servers, PCs , customers, software , networks, etc. ) - Information about the items (Service, maintenance, surveillance reports, status, responsibility, price, date of purchase, pictures, etc.) - Relationships / dependencies (parent, subordinate, used by, installed on, etc.) - Documentation, pictures, notes
  Items can be entered automatically from inventory tools, via import or manually.