LINQ to GraphQL Data

This article illustrates using LINQ to access tables within the GraphQL via the CData ADO.NET Data Provider for GraphQL. To achieve this, we will use LINQ to Entity Framework, which facilitates the generation of connections and can be seamlessly employed with any CData ADO.NET Data Providers to access data through LINQ.

See the help documentation for a guide to setting up an EF 6 project to use the provider.

1. In a new project in Visual Studio, right-click on the project and choose to add a new item. Add an ADO.NET Entity Data Model.
2. Choose EF Designer from Database and click Next.
3. Add a new Data Connection, and change your data source type to "CData GraphQL Data Source".

4. Enter your data source connection information.

   You must specify the URL of the GraphQL service. The driver supports two types of authentication:

   • Set AuthScheme to Basic. You must specify the User and Password of the GraphQL service.
   • Take a look at the OAuth section in the Help documentation for detailed instructions.

   Below is a typical connection string:

   AuthScheme=Basic;User=username;Password=password;URL=https://mysite.com;InitiateOAuth=GETANDREFRESH;

👁 Required connection properties for the data source. (QuickBooks is shown.)

5. If saving your entity connection to App.Config, set an entity name. In this example we are setting GraphQLEntities as our entity connection in App.Config.
6. Enter a model name and select any tables or views you would like to include in the model.

Using the entity you created, you can now perform select commands. For example:

GraphQLEntities context = new GraphQLEntities();

var usersQuery = from users in context.Users
 select users;

foreach (var result in usersQuery) {
 Console.WriteLine("{0} {1} ", result.Id, result.Name);
}

See "LINQ and Entity Framework" chapter in the help documentation for example queries of the supported LINQ.