How can I use ORM for a database whose schema is unknown before runtime?

Question

I am trying to use ORM with the following requirements:

1) Using the .NET Framework (the last platform is fine)
2) Must be able to use Sybase, Oracle, MSSQL interchangeably
3) The schema is mostly static, but there are dynamic parts.

I am a little familiar with SubSonic and NHibernate, but not deeply.
I get a disgusting feeling that ORM can do what I want, but I don’t know how to use it at the moment.

SubSonic is probably not optimal, since it currently does not support Sybase, and writing my own provider for it is now unavailable to my resources and capabilities.

For # 3 (above), there are a couple of metadata tables that describe tables that vendors can “stitch” with an existing database.
Let me name these MetaTables and MetaFields.

There is a basic static scheme that ORM (NHibernate ATM) handles perfectly.
However, the provider can add the table to the database (physically), while they also add data to the metadata tables to describe their structure.

I would really like to be able to somehow "feed" the ORM with this metadata (so that I understand it), and be able to manipulate the data at this point.

My main goal SQL-, .
SQL Sybase, Oracle MSSQL.

, ORM ,

. :

IDataReader rdr = ( "DynamicTable1" ). WHERE ( "ArbitraryId", 2).ExecuteReader();

( , , SubSonic , Sybase (. )

Answer 1

NHibernate . , ...

Answer 2

NHibernate, , ROI. ORM/SQL-, (, , , ).

SQL ( ), XML (Query Markup Language - QML). xmlDocument selects, wheres, groups .., SqlEngine, Sql . , , . Qmls .

Answer 3

ADO.NET Entity Framework?

MSDN: LINQ to Entities

, , , , , . , db .

, LINQ to Entities, OO, SQL-.

Answer 4

, ? ORM - , , orm ?

" , " - ?

, - , , . ( ORM)

Answer 5

IDataReader , . .