LINQ to HarperDB Data

This article illustrates using LINQ to access tables within the HarperDB via the CData ADO.NET Data Provider for HarperDB. 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 HarperDB Data Source".

4. Enter your data source connection information.

   Set the Server, User, and Password connection properties to connect to HarperDB. Set UseSSL to secure connections with TLS/SSL.

   Below is a typical connection string:

   Server=127.0.0.1;User=admin;Password=1234;

👁 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 HarperDBEntities 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 , update, delete, and insert commands. For example:

HarperDBEntities context = new HarperDBEntities();

var customersQuery = from customers in context.Customers
 select customers;

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

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