8.4.Using Microsoft Entity Frameworks to Access Ingres Schema Objects with Virtuoso
Abstract
This section details the steps required to provide Microsoft Entity Framework access to Ingres Schema Objects using the OpenLink Virtuoso Universal Server. This is achieved by linking the required Ingres 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 Ingres Schema objects linked into the Virtuoso Server.
Prerequisites. The following prerequisites must be in place for this solution to be possible.
Ingres DBMS. An Ingres DBMS hosting the required Schema Objects needs to be available. In this section the Ingres Tutorial sample database will be used to demonstrate the process.
An Ingres DBMS hosting the required Schema Objects needs to be available. In this section the Ingres Tutorial sample database will be used to demonstrate the process.
ODBC Driver for Ingres. An Ingres ODBC Driver is required for Linking the Ingres Schema Objects into the Virtuoso Server. The OpenLink ODBC Driver for Ingres will be used in this section, for which a functional ODBC Data source name of ingiima will be assumed to exist on the machine hosting the Virtuoso Server.
An Ingres ODBC Driver is required for Linking the Ingres Schema Objects into the Virtuoso Server. The OpenLink ODBC Driver for Ingres will be used in this section, for which a functional ODBC Data source name of ingiima 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
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.
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 Ingres 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. Thus ensure any tables to be used are defined as not nullable in the Ingres database schema before attempting to generate an EDM. In the case of the Ingres database all tables are not nullable, thus this should not be an issue in this case.
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. Thus ensure any tables to be used are defined as not nullable in the Ingres database schema before attempting to generate an EDM. In the case of the Ingres database all tables are not nullable, thus this should not be an issue in this case.