Connect an application

YCQL

YugabyteDB Java Driver for YCQL

Prerequisites

This tutorial assumes that you have:

installed YugabyteDB, created a universe and are able to interact with it using the YCQL shell. If not, follow these steps in Quick start.
installed Scala version 2.12 or later.
installed sbt 1.3.8 or later.

sbt

To build a Scala application using the Yugabyte Java Driver for YCQL, you must add the following sbt (Scala build tool) dependency to your application:

libraryDependencies += "com.yugabyte" % "cassandra-driver-core" % "3.8.0-yb-5"

Create the sbt build file

Create a sbt build file build.sbt and copy the following content into it.

name := "YBCqlHelloWorld"
version := "1.0"
scalaVersion := "2.12.11"
scalacOptions := Seq("-unchecked", "-deprecation")

// https://mvnrepository.com/artifact/com.yugabyte/cassandra-driver-core
libraryDependencies += "com.yugabyte" % "cassandra-driver-core" % "3.8.0-yb-5"

Write a sample Scala application

Copy the following contents into the file YBCqlHelloWorld.scala.

package com.yugabyte.sample.apps

import com.datastax.driver.core.Cluster
import com.datastax.driver.core.ResultSet
import com.datastax.driver.core.Row
import com.datastax.driver.core.Session


object YBCqlHelloWorld {

  def main(args: Array[String]): Unit = {
    try {
      // Create a Cassandra client.
      val cluster = Cluster.builder.addContactPoint("127.0.0.1").build
      val session = cluster.connect

      // Create keyspace 'ybdemo' if it does not exist.
      val createKeyspace = "CREATE KEYSPACE IF NOT EXISTS ybdemo;";
      val createKeyspaceResult = session.execute(createKeyspace);
      println("Created keyspace ybdemo");

      // Create table 'employee' if it does not exist.
      val createTable = """
        CREATE TABLE IF NOT EXISTS ybdemo.employee (
          id int PRIMARY KEY,
          name varchar,
          age int,
          language varchar
        );
      """
      val createResult = session.execute(createTable)
      println("Created table employee")

      // Insert a row.
      val insert = """
        INSERT INTO ybdemo.employee
        |(id, name, age, language)
        |VALUES
        |(1, 'John', 35, 'Scala');
        """.trim.stripMargin('|').replaceAll("\n", " ")
      val insertResult = session.execute(insert)
      println(s"Inserted data: ${insert}")

      // Query the row and print out the result.
      val select = """
        SELECT name, age, language
         FROM  ybdemo.employee
         WHERE id = 1;
      """
      val rows = session.execute(select).all
      val name = rows.get(0).getString(0)
      val age = rows.get(0).getInt(1)
      val language = rows.get(0).getString(2)
      println(
        s"""
          Query returned ${rows.size}
          |row: name=${name},
          |age=${age},
          |language=${language}
        """.trim.stripMargin('|').replaceAll("\n", " ")
      )

      // Close the client.
      session.close
      cluster.close
    } catch {
      case e: Throwable => println(e.getMessage)
    }

  } //  def main

} // object YBCqlHelloWorld

Build and run the application

To build the application, just run the following command.

$ sbt compile

To run the program, run the following command.

$ sbt run

You should see the following as the output.

Created keyspace ybdemo
Created table employee
Inserted data: INSERT INTO ybdemo.employee (id, name, age, language) VALUES (1, 'John', 35, 'Scala');
Query returned 1 row: name=John, age=35, language=Scala