Introduction to ScyllaDB with Java

1. Overview

In this tutorial, we’re going to explore ScyllaDB – a fast and scalable NoSQL Database. We’ll see its features and how to interact with it.

2. What Is ScyllaDB?

ScyllaDB is an open-source distributed NoSQL database. It supports the same protocol as Cassandra with significantly higher throughputs and lower latencies. It’s developed using C++ language.

ScyllaDB has three variants:

• ScyllaDB Open Source: It’s a free, open-source version. We’ll have full ownership and need to do the maintenance ourselves
• ScyllaDB Enterprise: It’s a paid version where we’ll get some premium features and 24/7 support. We’ll need to use our own infrastructure to install this variant
• ScyllaDB Cloud: It’s a cloud-based service provided by ScyllaDB where we don’t need to have our own infrastructure or do any installation and maintenance

2.1. Installation

We’ll use the open-source version and run it on a Docker container using the following command:

$ docker run --name scylla -p 9042:9042 -d scylladb/scylla

We’re exposing port number 9042 here. We’ll connect to the database using this port.

Now, let’s connect to the database, create a table and insert some data. We’ll write Java code to fetch this data.

Let’s execute the following command to connect to the database:

$ docker exec -it scylla cqlsh

Now let’s create a namespace with a simple replication strategy with factor 3:

CREATE KEYSPACE IF NOT EXISTS baeldung WITH replication = {'class': 'SimpleStrategy', 'replication_factor' : 3};

Let’s execute the following query to create a table and insert data:

CREATE COLUMNFAMILY IF NOT EXISTS baeldung.User (id bigint PRIMARY KEY, name text);
INSERT INTO baeldung.User (id, name) values (1, 'john doe');

3. Java Code Implementation

We’ll write a simple Java program that’ll connect to our locally deployed Scylla DB and execute queries.

3.1. Maven Dependency

Let’s add the Scylla core library dependency in our pom.xml file:

<dependency>
    <groupId>com.scylladb</groupId>
    <artifactId>java-driver-core</artifactId>
    <version>4.14.1.0</version>
</dependency>

3.2. Java Code

Let’s first add the connection URL to the application.yml file:

datastax-java-driver:
  basic:
    contact-points: 127.0.0.1:9042

We can refer to this documentation for more details on all the configurable values.

Now let’s fetch the user’s name that we’ve added previously:

try (CqlSession session = CqlSession.builder().build()) {
    ResultSet rs = session.execute("select * from baeldung.User");
    Row row = rs.one();
    return row.getString("name");
}

We can also use a query-builder to insert and fetch data. We’ll first need to add java-driver-query-builder Maven dependency to the pom.xml file:

<dependency>
    <groupId>com.scylladb</groupId>
    <artifactId>java-driver-query-builder</artifactId>
    <version>4.14.1.0</version>
</dependency>

Now we’ll write SELECT and INSERT builder statements in our code to fetch and insert data:

try (CqlSession session = CqlSession.builder().build()) {
    InsertInto insert = insertInto("baeldung", "User");
    SimpleStatement statement = insert.value("id", literal(2))
      .value("name", literal("dev user"))
      .build();
    ResultSet rs = session.execute(statement);
}

It’ll insert a new user with id = 2 and name = “dev user” in the table User of namespace baeldung. Now let’s create a SELECT statement to find this user by name:

try (CqlSession session = CqlSession.builder().build()) {
    Select query = selectFrom("baeldung", "User").all()
      .whereColumn("name").isEqualTo(literal("dev user"))
      .allowFiltering();;
    SimpleStatement statement = query.build();
    ResultSet rs = session.execute(statement);
    Row row = rs.one();
    assertEquals(2, row.getLong("id"));
    assertEquals("dev user", row.getString("name");
}

We can see that it’ll return the data we inserted with id = 2.

4. Conclusion

Here we’ve seen a quick introduction to ScyllaDB, learning how to install, connect, and execute queries, as well as how we can interact with it from our application.