Working with FHIR Data in LINQPad

The CData ADO.NET Provider for FHIR enables you to use standard ADO.NET interfaces like LINQ and the Entity Framework to work with FHIR data. This article will demonstrate the process of establishing a connection from LINQPad and executing LINQ queries.

Create the Data Model

After downloading and installing both the provider and LINQPad, create a new class library project within Visual Studio.

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

1. Right-click your project and click Add -> New Item -> ADO.NET Entity Data Model. In the resulting dialog, select Code First from database. Click New Connection and specify the connection string options in the resulting wizard.

   Set URL to the Service Base URL of the FHIR server. This is the address where the resources are defined in the FHIR server you would like to connect to. Set ConnectionType to a supported connection type. Set ContentType to the format of your documents. Set AuthScheme based on the authentication requirements for your FHIR server.

   Generic, Azure-based, AWS-based, and Google-based FHIR server implementations are supported.

   Sample Service Base URLs

   • Generic: http://my_fhir_server/r4b/
   • Azure: https://MY_AZURE_FHIR.azurehealthcareapis.com/
   • AWS: https://healthlake.REGION.amazonaws.com/datastore/DATASTORE_ID/r4/
   • Google: https://healthcare.googleapis.com/v1/projects/PROJECT_ID/locations/LOCATION/datasets/DATASET_ID/fhirStores/FHIR_STORE_ID/fhir/

   Generic FHIR Instances

   The product supports connections to custom instances of FHIR. Authentication to custom FHIR servers is handled via OAuth (read more about OAuth in the Help documentation. Before you can connect to custom FHIR instances, you must set ConnectionType to Generic.

   Below is a typical connection string:

   URL=http://test.fhir.org/r4b/;ConnectionType=Generic;ContentType=JSON;AuthScheme=None;

   👁 The required connection properties in the Entity Data Model Configuration Wizard. (JSON is shown.)
   

2. Select the desired tables and views and click Finish to create the data model.

   👁 The last step of the Entity Data Model Configuration Wizard, where tables are imported into the entity model.
   
3. Build the project. The generated files can be used to create the FHIR connection in LINQPad.

Connect to FHIR Data in LINQPad

After you have obtained the required connection properties and created the data model assembly, follow the steps below to start using the data model in LINQPad.

1. Open LINQPad and click Add Connection.

2. Select the "Use a typed data context from your own assembly" option.

3. Select Entity Framework DbContext.

   👁 The Choose Data Context dialog.
   

4. Click Browse next to the Path to Custom Assembly box and browse to your project folder. Browse to the .dll or .exe under the bin folder.

5. Select the name of the DbContext.
6. If you saved your connection string in App.Config, specify the path to the App.config.

You can now query FHIR data through LINQPad. For examples of the supported LINQ queries, see the "LINQ and Entity Framework" chapter in the help documentation.