Connect with the C# driver

DataStax recommends the Data API and clients for Serverless (Vector) databases. You can use the Data API to perform CQL operations on your table data in Serverless (Vector) databases.

DataStax recommends drivers only for Serverless (Non-Vector) databases, legacy applications that rely on a driver, or for CQL functions that aren’t supported by the Data API. For more information, see Compare connection methods.

To use the DataStax C# driver, you need to install the driver and its dependencies, and then connect the driver to your Astra DB Serverless database. Once connected, you can write scripts that use the driver to run commands against your database.

Prerequisites

Create a database.
Set the following environment variables:
- ASTRA_DB_ID: The database ID
- ASTRA_DB_REGION: A region where your database is deployed and where you want to connect to the database, such as us-east-2
- ASTRA_DB_KEYSPACE: A keyspace in your database, such as default_keyspace
- ASTRA_DB_APPLICATION_TOKEN: An application token with the Database Administrator role.
  
  The token.json has the following format:
  { "clientId": "CLIENT_ID", "secret": "CLIENT_SECRET", "token": "APPLICATION_TOKEN" }
  For driver authentication, you can use either clientId and secret or the literal string token and the AstraCS token value. If you are on an older driver version that doesn’t support the token option, then you might need to use clientId and secret. For more information, see Token details.
Download your database’s Secure Connect Bundle (SCB).
Download and install the current version of the Microsoft .NET Core SDK.

Install the C# driver

Create a new C# project:

mkdir csharpproject
cd csharpproject
dotnet new console

Add the C# driver dependencies to your project:
```
dotnet add package CassandraCSharpDriver -v VERSION
```
Make sure you use a driver version that is compatible with Astra DB. For more information, see DataStax driver matrix.

Connect the C# driver

Replace the code in Program.cs with the following connection code, replacing PATH_TO_SCB with the absolute path to your database’s Secure Connect Bundle (SCB) (secure-connect-DATABASE_NAME.zip):

Program.cs

using System;
using System.Linq;
using Cassandra;

namespace csharpproject
{
    class Program
    {
        static void Main(string[] args)
        {
            var session =
                Cluster.Builder()
                       .WithCloudSecureConnectionBundle(@"C:PATH_TO_SCB")
                       .WithCredentials("token", "ASTRA_DB_APPLICATION_TOKEN")
                       .Build()
                       .Connect();
        }
    }
}

After the connection code, add code to the Main method in Program.cs that runs a CQL query and prints the output to the console:
Program.cs
```
var rowSet = session.Execute("select * from system.local");
Console.WriteLine(rowSet.First().GetValue<string>("cluster_name"));
```
Save Program.cs, and then run your C# project with the dotnet runtime:
```
dotnet restore
dotnet build
dotnet run --no-build
```
Extend or modify this script to run other commands against your database or connect to other databases. For more information, see C# driver documentation and Developing applications with DataStax drivers.

Connect with the C# driver

Prerequisites

Install the C# driver

Connect the C# driver

See also

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