How to Access Sage 200 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 Sage 200 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 Sage 200 Entity Framework 6 assembly and the connection string.

   • Schema: Determines which Sage 200 edition you are connecting to. Specify either StandardUK or ProfessionalUK.
   • Subscription Key: Provides access to the APIs that are used to establish a connection. You will first need to log into the Sage 200 API website and subscribe to the API edition that matches your account. You can do so here: https://developer.columbus.sage.com/docs/services/api/uk. Afterwards, the subscription key may be found in your profile after logging into Sage 200.
   <configuration> ... <connectionStrings> <add name="Sage200Context" connectionString="Offline=False;SubscriptionKey=12345;Schema=StandardUK;InitiateOAuth=GETANDREFRESH" providerName="System.Data.CData.Sage200" /> </connectionStrings> <entityFramework> <providers> ... <provider invariantName="System.Data.CData.Sage200" type="System.Data.CData.Sage200.Sage200ProviderServices, System.Data.CData.Sage200.Entities.EF6" /> </providers> <entityFramework> </configuration> </code>
4. Add a reference to System.Data.CData.Sage200.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 Sage200Context. 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 Sage200Context : DbContext { public Sage200Context() { } protected override void OnModelCreating(DbModelBuilder modelBuilder) { // To remove the requests to the Migration History table Database.SetInitializer<Sage200Context>(null); // To remove the plural names modelBuilder.Conventions.Remove<PluralizingTableNameConvention>(); } }
7. Create another .cs file and name it after the Sage 200 entity you are retrieving, for example, Banks. 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("Banks")] public class Banks { [System.ComponentModel.DataAnnotations.Key] public System.String Id { get; set; } public System.String Code { get; set; } }
8. Now that you have created an entity, add the entity to your context class: public DbSet<Banks> Banks { set; get; }
9. With the context and entity finished, you are now ready to query the data in a separate class. For example: Sage200Context context = new Sage200Context(); context.Configuration.UseDatabaseNullSemantics = true; var query = from line in context.Banks select line;