Build a Scala application
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"
Working Example
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.
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