mlagace / Scqla

cassandra CQL driver for Scala

Scqla

A fully asynchronous Cassandra CQL driver for Scala using Akka IO.

##Highlights:

1. Directly construct objects from results.

2. Completely stateless, no sessions required. Fire any query from anywhere, anytime.

3. Load balance between cassandra nodes.

4. Get an Either as a result of all queries. No exceptions, just Scala goodness.

###Connect to cassandra cluster.

Scqla.connect

###Import from Scqla object

import Scqla._

###Create a new keyspace

query("CREATE KEYSPACE demodb WITH REPLICATION = {'class' : 'SimpleStrategy','replication_factor': 1}").map(_.fold(
  error => println(error),
  valid => {
    //do something
  }
))

###Set global keyspace

Note: This only works if you only connect to one node in Cassandra cluster. If that is not the case use full table qualifiers as shown in the examples here.

query("use demodb").map(_.fold(
  error => println(error),
  valid => { //do something
  }
))

###Create a new table

    query("""CREATE TABLE demodb.emp (
    		empID int,
    		deptID int,
    		alive boolean,
    		id uuid,
    		first_name varchar,
    		last_name varchar,
    		salary double,
    		age bigint,
        PRIMARY KEY (empID, deptID))""").map(_.fold(
      error => println(error),
      valid => {
        //do something
      }
    ))

###Execute prepared queries

    prepare("INSERT INTO demodb.emp (empID, deptID, alive, id, first_name, last_name, salary, age) VALUES (?, ?, ?, ?, ?, ?, ?, ?)").map(_.fold(
      error => println(error),
      valid => valid.execute(104, 15, true, new java.util.UUID(0, 0), "Hot", "Shot", 10000000.0, 98763L)))

###You can directly construct objects from the result.

###Case class list

case class Emp(empId: Int, deptId: Int, alive: Boolean, id: java.util.UUID, first: String, last: String, salary: Double, age: Long)

queryAs[Emp]("select empID, deptID, alive, id, first_name, last_name, salary, age from demodb.emp").map(_.fold(
  error => println(error),
  empList => {
    empList.foreach(e => s"First name of employee id ${e.empId} is ${e.first}")
  }
))

###Primitives list

queryAs[Int]("select empid from demodb.emp").map(_.fold(
  error => println(error),
  idList => {
    idList.foreach(println)
  }
))

###Strings

queryAs[String]("select first_name from demodb.emp").map(_.fold(
  error => println(error),
  nameList => {
    nameList.foreach(println)
  }
))

###Execute prepared queries and get results

prepare("select empID, deptID, alive, id, first_name, last_name, salary, age from demodb.emp where empid = ? and deptid = ?").map(_.fold(
  error => println(error),
  valid => valid.executeGet[Emp](104, 15).map(_.fold(
    error => println(error),
    empList => {
      empList.foreach(e => s"First name of employee id ${e.empId} is ${e.first}")
    }
  )
)))

###Drop keyspace

query("drop KEYSPACE demodb").map(_.fold(
  error => println(error),
  valid => {
    //do something
  }
))