Here are the important types of Cognos reporting tool:
Content Store:
It is set of database tables which are used by the Content Manager to store application data of the Cognos.
Content Manager:
The Cognos manager helps you to manage storage and retrieval of report specifications, configuration data, published packages, from the content store database.
Cognos Content Database:
Cognos content database is a self-contained database server which is used to host the content store database in demo environments when enterprise DMBS in unavailable.