This document summarizes how to connect to and query a Cassandra database using the Java driver. It covers connecting to a Cassandra cluster, executing DDL and DML statements, performing synchronous and asynchronous queries, using prepared statements, the query builder, tracing queries, and configuring load balancing policies.

1. Workshop
desarrollo Cassandra
Java
José Hernández
Isthari
jose.Hernandez@isthari.com

2. Dependencias
 Maven
<dependency>
<groupId>com.datastax.cassandra</groupId>
<artifactId>cassandra-driver-core</artifactId>
<version>2.0.1</version>
</dependency>

3. Cluster de cassandra

4. Conexión
 Cluster
Cluster cluster = Cluster.builder()
.addContactPoint(“10.202.203.105")
.addContactPoint(“10.202.203.106")
.build();

5. Conexión
 Cluster
Cluster cluster = Cluster.builder()
.addContactPoint(“10.202.203.105")
.addContactPoint(“10.202.203.106")
.build();
 Auto – discover
New Cassandra host /10.202.203.108
New Cassandra host /10.202.203.109
New Cassandra host /10.202.203.111
…

6. Desconexión
 Cluster
Cluster cluster = Cluster.builder()
.addContactPoint(“10.202.203.105")
.addContactPoint(“10.202.203.106")
.build();
 Desconectar
Cluster.close();

7. Statements
 Conectar a un keyspace
Session session = cluster.connect("webinar");

8. Statements
 Conectar a un keyspace
Session session = cluster.connect("webinar");
 DDL
session.execute("create table usuarios
( id uuid , nombre text, primary key (id)) ");

9. Statements
 Conectar a un keyspace
Session session = cluster.connect("webinar");
 DDL
session.execute("create table usuarios
( id uuid , nombre text, primary key (id)) ");
 DML
session.execute("insert into usuarios (id, nombre)
values (18c8dfee-…, 'Juan')");

10. Query
ResultSet resultSet = session.execute("select * from usuarios");

11. Query
ResultSet resultSet = session.execute("select * from usuarios");
for (Row row : resultSet){
…
}

12. Query
ResultSet resultSet = session.execute("select * from usuarios");
for (Row row : resultSet){
LOGGER.info(row.getUUID("id")+" - "+
row.getString("nombre"));
}

13. Bound statement
PreparedStatement stmt = session.prepare(
"insert into usuarios (id, nombre) values (?,?)");

14. Bound statement
PreparedStatement stmt = session.prepare(
"insert into usuarios (id, nombre) values (?,?)");
session.execute(
stmt.bind(UUID.randomUUID(), "Jose"));

15. Async queries

16. Async queries

17. Async queries
ResultSetFuture resultSet1 = session.executeAsync("select …
ResultSetFuture resultSet2 = session.executeAsync("select …
ResultSetFuture resultSet3 = session.executeAsync("select …

18. Async queries
ResultSetFuture resultSet1 = session.executeAsync("select …
ResultSetFuture resultSet2 = session.executeAsync("select …
ResultSetFuture resultSet3 = session.executeAsync("select …
for (Row row : resultSet1.getUninterruptibly()){
...
}

19. Async queries
ResultSetFuture resultSet1 = session.executeAsync("select …
ResultSetFuture resultSet2 = session.executeAsync("select …
ResultSetFuture resultSet3 = session.executeAsync("select …
for (Row row : resultSet1.getUninterruptibly()){
...
}
for (Row row : resultSet2
.getUninterruptibly(1000, TimeUnit.MILLISECONDS)){
...
}

20. Query builder
Statement stmt1 = QueryBuilder
.select()

21. Query builder
Statement stmt1 = QueryBuilder
.select()
.from("usuarios")

22. Query builder
Statement stmt1 = QueryBuilder
.select()
.from("usuarios")
.where(eq("id", UUID.fromString("0bd4f5c9…")));

23. Query builder
Statement stmt1 = QueryBuilder
.select()
.from("usuarios")
.where(eq("id", UUID.fromString("0bd4f5c9…")));
session.execute(stmt1);

24. Query builder
Statement stmt = QueryBuilder.insertInto(“usuarios")

25. Query builder
Statement stmt = QueryBuilder.insertInto(“usuarios")
.value("id", UUID.randomUUID())
.value(“nombre", “Felipe")

26. Query builder
Statement stmt = QueryBuilder.insertInto(“usuarios")
.value("id", UUID.randomUUID())
.value(“nombre", “Felipe")
.setConsistencyLevel(ConsistencyLevel.ANY)

27. Query builder
Statement stmt = QueryBuilder.insertInto(“usuarios")
.value("id", UUID.randomUUID())
.value(“nombre", “Felipe")
.setConsistencyLevel(ConsistencyLevel.ANY);
session.execute(stmt);

28. Tracing
stmt.enableTracing();
ExecutionInfo info = session.execute(stmt).getExecutionInfo();
QueryTrace trace = info.getQueryTrace ();

29. Load balancing policy
 RoundRobinPolicy
 DCAwareRoundRobinPolicy
 TokenAware

30. Load balancing policy
 RoundRobinPolicy
 DCAwareRoundRobinPolicy
 TokenAware
Ejemplo: DCAwareRoundRobinPolicy
Cluster cluster = Cluster.builder()
…
.withLoadBalancingPolicy(
new DCAwareRoundRobinPolicy("localDC"))

31. Preguntas y sugerencias
Gracias por asistir