$all Operator in Casbah

Question

Could you please give me an example of how to use the $all operator for my two elemMatch objects?

val elemMatch1 = foo()
val elemMatch2 = bar()

How can I perform the query of $all( elemMatch1, elemMatch2) (all documents where elemMatch1 and elemMatch2)?

Answer 1

I'm not sure how much sense it makes to mix $all and $elemMatch but from the docs $all follows:

{ <field>: { $all: [ <value> , <value1> ... ] }

$elemMatch follows:

{ array: { $elemMatch: <document> } }

Unfortunately, the casbah DSL won't help there as $all requires a list and $elemMatch expects a string, so you have to manually have to build the document:

import com.mongodb.casbah.Imports._
val coll = MongoClient()("test")("testB")

coll += MongoDBObject("array" -> List(
            MongoDBObject("value1" -> 1, "value2" -> 0),
            MongoDBObject("value1" -> 1, "value2" -> 2)
        ))

val elemMatch = MongoDBObject("$elemMatch" -> MongoDBObject("value1" -> 1, "value2" -> 2))
val query = "array" $all List(elemMatch)

coll.find(query).count