A fully asynchronous Cassandra CQL driver for Scala using Akka IO.
##Highlights:
-
Directly construct objects from results.
-
Completely stateless, no sessions required. Fire any query from anywhere, anytime.
-
Load balance between cassandra nodes.
-
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
}
))
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