Using Microsoft Entity Frameworks to Access Sybase Schema Objects with Virtuoso

This document details the steps required to provide Microsoft Entity Framework access to Sybase Schema Objects using the OpenLink Virtuoso Universal Server. This is achieved by linking the required Sybase 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 Sybase Schema objects linked into the Virtuoso Server.

Prerequisites

The following prerequisites must be in place for this solution to be possible.

Sybase DBMS

A Sybase DBMS hosting the required Schema Objects needs to be available. In this document the Sybase pubs2 sample database will be used to demonstrate the process.

ODBC Driver for Sybase

A Sybase ODBC Driver is required for Linking the Sybase Schema Objects into the Virtuoso Server. The OpenLink ODBC Driver for Sybase will be used in this document, for which a functional ODBC Data source name of syb15ma 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 Sybase 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. Therefor, ensure any primary keys to be used are defined as not nullable in the Sybase database schema before attempting to generate an EDM. In the case of the Sybase pubs2 database, all tables are non nullable. Thus, this should not be an issue in this case.

Install and configure OpenLink ODBC Driver for Sybase

The Virtuoso Virtual Database engine uses ODBC as the connectivity mechanism for linking remote database objects into its local schema. Thus, a Sybase ODBC Driver must be available with a suitably configured DSN for connecting to the target database. The OpenLink ODBC Drivers for Sybase have been used in this document, although in theory any Sybase ODBC Driver can be used.

Installation instructions for the OpenLink ODBC Driver for Sybase are available from:

• Product Installation & Basic Configuration (ODBC)

Install and configure OpenLink Virtuoso Universal Server

• Install and configure OpenLink Virtuoso Universal Server

Linking Sybase tables into Virtuoso

• Linking Sybase tables into OpenLink Virtuoso

Creating a Visual Studio hosted Entity Data Model (EDM)

• Creating an EDM in Visual Studio 2008

In the event that no entity-linking associations are automatically created (as is the case here with Sybase), the associations will need to be created manually. The following document details this process —

• Manually creating EDM Associations (FKs)

Using EDM to create Entity Framework based applications

Now that a Microsoft Entity Data Model has been created for the Sybase pubs2 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