i have to install mdm in my pc, what are all the needed software and hardware requirements? is the server necessary for the installation? can't i do it in my pc?
As Michael stated, it's best to run server from a central server, but can be acheived locally if you want to develop a testing scenario. Along with the MDM components you will need a server to run MDM on (SQL, Oracle, DB2, MaxDB). For a test scenario you may be able to run a free version of SQL Express, but it definitely wouldn't be recommended for a production scenario.
MDM has several server components (like MDM Server, Import Server, Syndication Server) and several client components (like Data Manager, Import Manager, and so on).
The server components can be installed centrally on a server PC. Of course you can install them locally on your PC, but centrally makes more sense if other user should work with MDM, too. The client components can be installed locally on your PC. They enable you to access the central server.
For details on the software, required hardware, and so on you should check the documents available on <a href="http://service.sap.com/installmdm">MDM Documentation Center</a>. You'll find there the reference guides for the client components as well as a IT Configuration guide that describes how to set up your MDM landscape.