How to Access SAP Ariba Procurement 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 Procurement 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 Procurement Entity Framework 6 assembly and the connection string.

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

   • ANID: Your Ariba Network ID.
   • ANID: Specify which API you would like the provider to retrieve SAP Ariba data from. Select the Buyer or Supplier API based on your business role (possible values are PurchaseOrdersBuyerAPIV1 or PurchaseOrdersSupplierAPIV1).
   • Environment: Indicate whether you are connecting to a test or production environment (possible values are TEST or PRODUCTION).

   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="SAPAribaProcurementContext" connectionString="Offline=False;ANID=AN02000000280;API=PurchaseOrdersBuyerAPI-V1;APIKey=wWVLn7WTAXrIRMAzZ6VnuEj7Ekot5jnU;AuthScheme=OAuthClient;InitiateOAuth=GETANDREFRESH;" providerName="System.Data.CData.SAPAribaProcurement" />
    </connectionStrings>
    <entityFramework>
    <providers>
    ... 
    <provider invariantName="System.Data.CData.SAPAribaProcurement" type="System.Data.CData.SAPAribaProcurement.SAPAribaProcurementProviderServices, System.Data.CData.SAPAribaProcurement.Entities.EF6" />
    </providers>
    <entityFramework>
   </configuration>
   </code> 
   

4. Add a reference to System.Data.CData.SAPAribaProcurement.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 SAPAribaProcurementContext. 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 SAPAribaProcurementContext : DbContext {
    public SAPAribaProcurementContext() { }
   
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
    // To remove the requests to the Migration History table
    Database.SetInitializer<SAPAribaProcurementContext>(null); 
    // To remove the plural names 
    modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
    } 
   }
   

7. Create another .cs file and name it after the SAP Ariba Procurement entity you are retrieving, for example, Orders. 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("Orders")]
   public class Orders {
    [System.ComponentModel.DataAnnotations.Key] 
    public System.String DocumentNumber { get; set; }
    public System.String Revision { get; set; }
   }
    
   

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

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

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

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