I want to create a database from HERE and Google Maps to combine with my data. Then I create an application that can use this database. Basically I want to host the server with Google and here map data combine with my data. How should I proceed? Is it possible to combine my data in to these maps data.
Harshit, this is a bit of an open-ended question where I'm not sure what is your current setup, what technologies are you using or going to use, etc. Perhaps if give us more details, we can help you more specifically.
With such a general question, I give you a general answer:
Both HERE and Google Maps have JS APIs. I would start with studying those:
Then I would probably mash them together with your layers using OpenLayers: http://openlayers.org/