Scala:Applied Machine Learning

Extracting objects from the database

We now have a database populated with a few users. Let's query this database from the REPL:

scala> import com.mongodb.casbah.Imports._
import com.mongodb.casbah.Imports._

scala> val collection = MongoClient()("github")("users")
MongoCollection = users

scala> val maybeUser = collection.findOne
Option[collection.T] = Some({ "_id" : { "$oid" : "562e922546f953739c43df02"} , "github_id" : 1 , "login" : "mojombo" , "repos" : ...

The findOne method returns a single DBObject object wrapped in an option, unless the collection is empty, in which case it returns None. We must therefore use the get method to extract the object:

scala> val user = maybeUser.get
collection.T = { "_id" : { "$oid" : "562e922546f953739c43df02"} ...