How to Access HCL Domino 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 HCL Domino 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 HCL Domino Entity Framework 6 assembly and the connection string.

   Connecting to Domino

   To connect to Domino data, set the following properties:

   • URL: The host name or IP of the server hosting the Domino database. Include the port of the server hosting the Domino database. For example: http://sampleserver:1234/
   • DatabaseScope: The name of a scope in the Domino Web UI. The driver exposes forms and views for the schema governed by the specified scope. In the Domino Admin UI, select the Scopes menu in the sidebar. Set this property to the name of an existing scope.

   Authenticating with Domino

   Domino supports authenticating via login credentials or an Entra ID (formerly Azure AD) OAuth application:

   Login Credentials

   To authenticate with login credentials, set the following properties:

   • AuthScheme: Set this to "OAuthPassword"
   • User: The username of the authenticating Domino user
   • Password: The password associated with the authenticating Domino user

   The driver uses the login credentials to automatically perform an OAuth token exchange.

   EntraID (formerly AzureAD)

   This authentication method uses Entra ID (formerly Azure AD) as an IdP to obtain a JWT token. You need to create a custom OAuth application in Entra ID (formerly Azure AD) and configure it as an IdP. To do so, follow the instructions in the Help documentation. Then set the following properties:

   • AuthScheme: Set this to "EntraID (formerly AzureAD)"
   • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
   • OAuthClientId: The Client ID obtained when setting up the custom OAuth application.
   • OAuthClientSecret: The Client secret obtained when setting up the custom OAuth application.
   • CallbackURL: The redirect URI defined when you registered your app. For example: https://localhost:33333
   • AzureTenant: The Microsoft Online tenant being used to access data. Supply either a value in the form companyname.microsoft.com or the tenant ID.

     The tenant ID is the same as the directory ID shown in the Azure Portal's Entra ID (formerly Azure AD) > Properties page.

   <configuration>
    ... 
    <connectionStrings>
    <add name="DominoContext" connectionString="Offline=False;Server=https://domino.corp.com;AuthScheme=OAuthPassword;User=my_domino_user;Password=my_domino_password;" providerName="System.Data.CData.Domino" />
    </connectionStrings>
    <entityFramework>
    <providers>
    ... 
    <provider invariantName="System.Data.CData.Domino" type="System.Data.CData.Domino.DominoProviderServices, System.Data.CData.Domino.Entities.EF6" />
    </providers>
    <entityFramework>
   </configuration>
   </code> 
   

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

7. Create another .cs file and name it after the HCL Domino entity you are retrieving, for example, ByName. 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("ByName")]
   public class ByName {
    [System.ComponentModel.DataAnnotations.Key] 
    public System.String Name { get; set; }
    public System.String Address { get; set; }
   }
    
   

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

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

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

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