How to Access SAP 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 data through the CData ADO.NET Provider, providing you with more flexibility and control.

Getting Started

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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 Entity Framework 6 assembly and the connection string.

   You can connect to SAP systems using either librfc32.dll, librfc32u.dll, NetWeaver, or Web Services (SOAP). Set the ConnectionType connection property to CLASSIC (librfc32.dll), CLASSIC_UNICODE (librfc32u.dll), NETWEAVER, or SOAP.

   If you are using the SOAP interface, set the Client, RFCUrl, SystemNumber, User, and Password properties, under the Authentication section.

   Otherwise, set Host, User, Password, Client, and SystemNumber.

   Note: We do not distribute the librfc32.dll or other SAP assemblies. You must find them from your SAP installation and install them on your machine.

   For more information, see this guide on obtaining the connection properties needed to connect to any SAP system.

   <configuration>
    ... 
    <connectionStrings>
    <add name="SAPERPContext" connectionString="Offline=False;Host=sap.mydomain.com;User=EXT90033;Password=xxx;Client=800;System Number=09;ConnectionType=Classic;Location=C:/mysapschemafolder;" providerName="System.Data.CData.SAPERP" />
    </connectionStrings>
    <entityFramework>
    <providers>
    ... 
    <provider invariantName="System.Data.CData.SAPERP" type="System.Data.CData.SAPERP.SAPERPProviderServices, System.Data.CData.SAPERP.Entities.EF6" />
    </providers>
    <entityFramework>
   </configuration>
   </code> 
   

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

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

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

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

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

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