WCF database wrapper

I need to do a WCF service to wrap up the database access. I do not want the service to be bind to any specific database. In fact, it will only receives a query and returns a dataset. no treatement on the data will be done in the service so I want pure performance but it need to be secure too.

Actually, I think using perCall session, net.tcp binding and certificate autentification on both side. (it's a WAN app)

Still, can someone give some advices on the configuration that I should use?(Type of Session,Type of binding,Type of security,etc..)

It sounds like you could take advantage of WCF Data Services.

WCF Data Services (formerly known as "ADO.NET Data Services") is a component of the .NET Framework that enables you to create services that use the Open Data Protocol (OData) to expose and consume data over the Web or intranet by using the semantics of representational state transfer (REST). OData exposes data as resources that are addressable by URIs. Data is accessed and changed by using standard HTTP verbs of GET, PUT, POST, and DELETE. OData uses the entity-relationship conventions of the Entity Data Model to expose resources as sets of entities that are related by associations.