Core component

The core component is responsible for maintaining a pool of connections to the cluster and executes the statements based on client configuration.

Even though the core component allows low-level fine tuning, (for example, load-balancing policies to determine which node to use for each query), you interact using high-level objects like the ISession that represents a pool of connections to the cluster.

The other three components use the core component to execute statements and to handle the encoding and decoding of data.

Quick Start

Here’s a short program that connects to Cassandra and executes a query:

var cluster = Cluster.Builder()
   .AddContactPoints("host1", "host2", "host3")
   .Build();                                                 // (1)
var session = cluster.Connect("sample_keyspace");            // (2)
var rs = session.Execute("SELECT * FROM sample_table");      // (3)
foreach (var row in rs)
{
   var value = row.GetValue<int>("sample_int_column");       // (4)
   //do something with the value
}

Brief description of this code snippet (see the number, e.g., // (1)):

  1. Cluster is the main entry point of the driver. It holds the known state of the actual Cassandra cluster. It is thread-safe, you should create a single instance (per target Cassandra cluster), and share it throughout your application;
  2. Session is what you use to execute queries. It is thread-safe, you should create a single instance (per Cluster instance), and share it throughout your application;
  3. Here we use Execute to send a query to Cassandra. This returns a RowSet, which is an IEnumerable of Row objects. On the next line, we extract the first row (which is the only one in this case);
  4. Extract the value of the first (and only) column from the row.

Always close the Cluster and Session once you’re done with them, in order to free underlying resources (TCP connections, thread pools…). You can use Dispose, Shutdown or ShutdownAsync.

This example uses the synchronous API. Most methods have asynchronous equivalents (look for *Async variants that return a Task).