Using Microsoft Entity Frameworks to Access DB2 Schema Objects with Virtuoso This document details the steps required to provide Microsoft Entity Framework access to DB2 Schema Objects using the OpenLink Virtuoso Universal Server. This is achieved by linking the required DB2 Schema objects into Virtuoso using its built-in Virtual Database engine and then using the Virtuoso ADO.NET Entity Framework provider to query the remote DB2 Schema objects linked into the Virtuoso Server. Prerequisites The following prerequisites must be in place for this solution to be possible. DB2 DBMS A DB2 DBMS hosting the required Schema Objects needs to be available. In this document the DB2 sample database will be used to demonstrate the process. ODBC Driver for DB2 A DB2 ODBC Driver is required for Linking the DB2 Schema Objects into the Virtuoso Server. The OpenLink ODBC Driver for DB2 will be used in this document, for which a functional ODBC Data source name of db2v8ma will be assumed to exist on the machine hosting the Virtuoso Server. Virtuoso Universal Server An Virtuoso installation including the Virtuoso Universal Server and ADO.NET Entity Framework Provider is required. The Virtuoso components used must be Release 5.10.x or above, this being the minimum version containing support for Microsoft Entity Frameworks. Microsoft Visual Studio 2008 SP1 Microsoft Visual Studio 2008 Service Pack 1 is required, this being the only version containing the necessary Entity Framework support available at the time of writing. Tasks Ensure DB2 Primary Keys (PKs) are not nullable The Visual Studio 2008 Entity Data Model (EDM) requires that all primary keys are NOT Nullable. It will fail to generate an EDM, if any are. Therefore, ensure any tables to be used are defined as not nullable in the DB2 database schema before attempting to generate an EDM. In the case of the DB2 sample database, all primary keys are non nullable. Thus, this should not be an issue in this case. Install and configure OpenLink ODBC Driver for DB2 The Virtuoso Virtual Database engine uses ODBC as the connectivity mechanism for linking remote database objects into its local schema. Thus, a DB2 ODBC Driver must be available with a suitably configured DSN for connecting to the target database. The OpenLink ODBC Drivers for DB2 have been used in this document, although in theory any DB2 ODBC Driver can be used.Installation instructions for the OpenLink ODBC Driver for DB2 are available from: Product Installation & Basic Configuration (ODBC) Install and configure OpenLink Virtuoso Universal Server Install and configure OpenLink Virtuoso Universal Server Linking DB2 tables into Virtuoso Linking DB2 tables into OpenLink Virtuoso Creating a Visual Studio hosted Entity Data Model (EDM) Creating EDM in Visual Studio 2008 Using EDM to create Entity Framework based applications Now that a Microsoft Entity Data Model has been created for the DB2 sample database, Entity Framework applications can be created to make use of it. Entity Frameworks based ADO.NET Data Service Entity Framework Data Service Visual Studio Windows Form Application Windows DataGrid Form Application