LINQ to AlloyDB Data

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

4. Enter your data source connection information.

   The following connection properties are usually required in order to connect to AlloyDB.

   • Server: The host name or IP of the server hosting the AlloyDB database.
   • User: The user which will be used to authenticate with the AlloyDB server.
   • Password: The password which will be used to authenticate with the AlloyDB server.

   You can also optionally set the following:

   • Database: The database to connect to when connecting to the AlloyDB Server. If this is not set, the user's default database will be used.
   • Port: The port of the server hosting the AlloyDB database. This property is set to 5432 by default.

   Authenticating with Standard Authentication

   Standard authentication (using the user/password combination supplied earlier) is the default form of authentication.

   No further action is required to leverage Standard Authentication to connect.

   Authenticating with pg_hba.conf Auth Schemes

   There are additional methods of authentication available which must be enabled in the pg_hba.conf file on the AlloyDB server.

   Find instructions about authentication setup on the AlloyDB Server here.

   Authenticating with MD5 Authentication

   This authentication method must be enabled by setting the auth-method in the pg_hba.conf file to md5.

   Authenticating with SASL Authentication

   This authentication method must be enabled by setting the auth-method in the pg_hba.conf file to scram-sha-256.

   Authenticating with Kerberos

   The authentication with Kerberos is initiated by AlloyDB Server when the ∏ is trying to connect to it. You should set up Kerberos on the AlloyDB Server to activate this authentication method. Once you have Kerberos authentication set up on the AlloyDB Server, see the Kerberos section of the help documentation for details on how to authenticate with Kerberos.

   Below is a typical connection string:

   User=alloydb;Password=admin;Database=alloydb;Server=127.0.0.1;Port=5432

👁 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 AlloyDBEntities 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:

AlloyDBEntities context = new AlloyDBEntities();

var ordersQuery = from orders in context.Orders
 select orders;

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

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