dynamic query generation (adhoc queries)

I have an application where end users create adhoc reports by defining their options through a wizard where
1) The user selects the table(s) he wants to query
2) defines the joins for these tables
3) defines the list of fields he requires
4) supplies the filter criteria for the records to return

and returns a list of records based on the above selections
The applications holds all the necessary metadata needed to perform the query (connection string, tables names etc) and creates the sql string to execute

My question is if i can replace my existing code to use open access for the entire process of ad hoc queries.
main concerns are :
1) Can i define in code the tables to use for the model
2) can i define the metadata in code (connection string, mappings etc)
3)  define the criteria for the where clause
4) define criteria for group by clause


Giannis