What is a microcube
Microcube is the bulk of data u get once u have run the query.
when we run the report, data is extracted from database and it comes in the form of microcube, and when it get displayed in the report is actually coming from microcube.
in the simple terms, microcube is logicla description of Bulk of data for perticular report, so that data can be viewed in the different ways, by performing slice and dice, or drilling etc.
When user hit a query its run through BO server to Database and return result back to BO server where BO Server make MicroCube (itself inside) and make all possible combination of the query in the MicroCube and you see the report on screen.