How to Access SAP Ariba Source Data Using Entity Framework

Microsoft Entity Framework serves as an object-relational mapping framework for working with data represented as objects. Although Visual Studio offers the ADO.NET Entity Data Model wizard to automatically generate the Entity Model, this model-first approach may present challenges when your data source undergoes changes or when you require greater control over entity operations. In this article, we will delve into the code-first approach for accessing SAP Ariba Source data through the CData ADO.NET Provider, providing you with more flexibility and control.

1. Open Visual Studio and create a new Windows Form Application. This article uses a C# project with .NET 4.5.
2. Run the command 'Install-Package EntityFramework' in the Package Manger Console in Visual Studio to install the latest release of Entity Framework.

3. Modify the App.config file in the project to add a reference to the SAP Ariba Source Entity Framework 6 assembly and the connection string.

   In order to connect with SAP Ariba Source, set the following:

   • API: Specify which API you would like the provider to retrieve SAP Ariba data from. Select the Supplier, Sourcing Project Management, or Contract API based on your business role (possible values are SupplierDataAPIWithPaginationV4, SourcingProjectManagementAPIV2, or ContractAPIV1).
   • DataCenter: The data center where your account's data is hosted.
   • Realm: The name of the site you want to access.
   • Environment: Indicate whether you are connecting to a test or production environment (possible values are TEST or PRODUCTION).

   If you are connecting to the Supplier Data API or the Contract API, additionally set the following:

   • User: Id of the user on whose behalf API calls are invoked.
   • PasswordAdapter: The password associated with the authenticating User.

   If you're connecting to the Supplier API, set ProjectId to the Id of the sourcing project you want to retrieve data from.

   Authenticating with OAuth

   After setting connection properties, you need to configure OAuth connectivity to authenticate.

   • Set AuthScheme to OAuthClient.
   • Register an application with the service to obtain the APIKey, OAuthClientId and OAuthClientSecret.

     For more information on creating an OAuth application, refer to the Help documentation.

   Automatic OAuth

   After setting the following, you are ready to connect:

   APIKey: The Application key in your app settings. OAuthClientId: The OAuth Client Id in your app settings. OAuthClientSecret: The OAuth Secret in your app settings.

   When you connect, the provider automatically completes the OAuth process:

   1. The provider obtains an access token from SAP Ariba and uses it to request data.
   2. The provider refreshes the access token automatically when it expires.
   3. The OAuth values are saved in memory relative to the location specified in OAuthSettingsLocation.

   <configuration>
    ... 
    <connectionStrings>
    <add name="SAPAribaSourceContext" connectionString="Offline=False;API=SupplierDataAPIWithPagination-V4;APIKey=wWVLn7WTAXrIRMAzZ6VnuEj7Ekot5jnU;Environment=SANDBOX;Realm=testRealm;AuthScheme=OAuthClient;InitiateOAuth=GETANDREFRESH;" providerName="System.Data.CData.SAPAribaSource" />
    </connectionStrings>
    <entityFramework>
    <providers>
    ... 
    <provider invariantName="System.Data.CData.SAPAribaSource" type="System.Data.CData.SAPAribaSource.SAPAribaSourceProviderServices, System.Data.CData.SAPAribaSource.Entities.EF6" />
    </providers>
    <entityFramework>
   </configuration>
   </code> 
   

4. Add a reference to System.Data.CData.SAPAribaSource.Entities.EF6.dll, located in the lib -> 4.0 subfolder in the installation directory.
5. Build the project at this point to ensure everything is working correctly. Once that's done, you can start coding using Entity Framework.
6. Add a new .cs file to the project and add a class to it. This will be your database context, and it will extend the DbContext class. In the example, this class is named SAPAribaSourceContext. The following code example overrides the OnModelCreating method to make the following changes:
   • Remove PluralizingTableNameConvention from the ModelBuilder Conventions.
   • Remove requests to the MigrationHistory table.

   using System.Data.Entity;
   using System.Data.Entity.Infrastructure;
   using System.Data.Entity.ModelConfiguration.Conventions;
   
   class SAPAribaSourceContext : DbContext {
    public SAPAribaSourceContext() { }
   
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
    // To remove the requests to the Migration History table
    Database.SetInitializer<SAPAribaSourceContext>(null); 
    // To remove the plural names 
    modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
    } 
   }
   

7. Create another .cs file and name it after the SAP Ariba Source entity you are retrieving, for example, Vendors. In this file, define both the Entity and the Entity Configuration, which will resemble the example below:

   using System.Data.Entity.ModelConfiguration;
   using System.ComponentModel.DataAnnotations.Schema;
   
   [System.ComponentModel.DataAnnotations.Schema.Table("Vendors")]
   public class Vendors {
    [System.ComponentModel.DataAnnotations.Key] 
    public System.String SMVendorID { get; set; }
    public System.String Category { get; set; }
   }
    
   

8. Now that you have created an entity, add the entity to your context class:

   public DbSet<Vendors> Vendors { set; get; }
   

9. With the context and entity finished, you are now ready to query the data in a separate class. For example:

   SAPAribaSourceContext context = new SAPAribaSourceContext();
   context.Configuration.UseDatabaseNullSemantics = true;
   var query = from line in context.Vendors select line;