Abstract

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

Prerequisites

Progress OpenEdge 10.  A Progress DBMS hosting the required Schema Objects needs to be available. In this section, the isports sample database will be used to demonstrate the process.

A Progress DBMS hosting the required Schema Objects needs to be available. In this section, the isports sample database will be used to demonstrate the process.

OpenLink ODBC Driver for Progress (SQL-92).  A Progress ODBC Driver is required to link the Progress Schema Objects into the Virtuoso Server. The OpenLink ODBC Driver for Progress (SQL-92) will be used in this section, for which a functional ODBC Data source name of "prs101c " will be assumed to exist on the machine hosting the Virtuoso Server.

A Progress ODBC Driver is required to link the Progress Schema Objects into the Virtuoso Server. The OpenLink ODBC Driver for Progress (SQL-92) will be used in this section, for which a functional ODBC Data source name of "prs101c " will be assumed to exist on the machine hosting the Virtuoso Server.

OpenLink Virtuoso 5.10.x.  An OpenLink Virtuoso Universal Server installation including the Virtuoso Universal Server and ADO.NET Entity Framework Provider is required. The Virtuoso components must be Release 5.10.x or above, this being the minimum version containing support for Microsoft Entity Frameworks.

An OpenLink Virtuoso Universal Server installation including the Virtuoso Universal Server and ADO.NET Entity Framework Provider is required. The Virtuoso components 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 with Service Pack 1 is required, this being the only version containing the necessary Entity Framework support available at the time of writing.

Microsoft Visual Studio 2008 with Service Pack 1 is required, this being the only version containing the necessary Entity Framework support available at the time of writing.

Tasks

Ensure Progress Primary Keys (PKs) are not nullable.  The Visual Studio 2008 Entity Data Model (EDM) requires that all primary keys are NOT Nullable, and will fail to generate an EDM if any are nullable. Thus ensure any tables to be used are defined as not nullable in the Progress database schema before attempting to generate an EDM.

The Visual Studio 2008 Entity Data Model (EDM) requires that all primary keys are NOT Nullable, and will fail to generate an EDM if any are nullable. Thus ensure any tables to be used are defined as not nullable in the Progress database schema before attempting to generate an EDM.

It seems that, by default, several Primary Keys (PKs) in the isports database allows <NULL> values. It seems somewhat nonsensical - that a unique key used, specifically, to identify a row in a table can be allowed to be <NULL>.

This issue is best addressed directly in the database schema, by redefining those PKs that allow <NULL> so as not to allow <NULL>. Progress does not seem to talk in terms of <NULL>, instead using the term "Mandatory"

The following section will provide more specific details about how to ensure Progress PKs are not nullable:

  • Ensuring Progress PKs are not nullable