CODEWITHSUNDEEP
cassandradatastax-java-driverjava
gsf
gsf

Reputation: 7252

Cassandra com.datastax.driver open session to keyspace that might not exists

I am working on project that uses cassandra as a NoSql database. I am trying to setup my test framework to be able to work with an arbitrary keyspace to avoid collisions between different tests running at the same time.

I would like to be able to create session against keyspace that might not exists. Essentially what I want is to first check if it exists and if not to create it, and then to connect.

It seems that the Api has catch 22 because in order I to execute command (that could create keyspace) I already have to have connection to an existing keyspace.

What I am missing?

Upvotes: 3

Views: 3182

Answers (1)

Aaron
Aaron

Reputation: 57788

Have a look through the tutorials in the DataStax documentation, and you should be able to come up with a way to do this. The first part illustrates how to connect to the database cluster. It walks you through coming up with a simple connect method that is not specific to a keyspace.

private Cluster cluster;

public void connect(String node) {
   cluster = Cluster.builder()
         .addContactPoint(node)
         .build();
}

The next part discusses how to use a session object to execute CQL statements. You could probably query the schema_keyspaces table to see if the keyspace in question exists with something like this:

Session session = cluster.connect();
ResultSet results = session.execute("SELECT * FROM system.schema_keyspaces " +
    "WHERE keyspace_name = 'myKeyspaceNameGoesHere';");

The tutorial then shows specifically how to create a new keyspace via the Java Driver.

session.execute("CREATE KEYSPACE myKeyspaceNameGoesHere WITH replication " + 
      "= {'class':'SimpleStrategy', 'replication_factor':3};");

Note that I have pulled the code here from the examples in the docs. You will want to substitute your own keyspace name, replication strategy and factor.

Upvotes: 5

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