How to update / insert a MongoDB sub document with Monger? - mongodb

Question

I'm using Clojure's Monger library to connect to a MongeoDB database.
I want to update, insert & remove subdocuments in my Mongo database. MongoDB's $push modifier lets me do this on the root of the searched document. But I want to be able to $push onto a sub-collection. Looking at Monger's tests, it looks possible. But I want to be sure I can push to the child-collection of the 3rd parent. Can Monger do something like this?
(mgcol/update mycollection { :my-criteria-key "my-criteria-value" } { $push { "parent.3.child-collection" "fubar" }} )
Even better would be the ability to have a $where clause in my $push. Is something like this possible?
(mgcol/update mycollection
{ :doc-criteria-key "doc-criteria-value" }
{ $push
{ { $where { parent.child.lastname: 'Smith' } }
"fubar" } }
)
But even on a basic level, when I try the following command in my repl, I get the below error.
The "fubar" database definitely exists
I'm definitely connected to the DB
The { :owner "fubar#gmail.com" } criteria is definitely valid; and
I tried both "content.1.content" and "content.$.content":
repl => (mc/update "fubar" { :owner "fubar#gmail.com" } { $push { "content.1.content" { "fu" "bar" } } } )
ClassCastException clojure.lang.Var$Unbound cannot be cast to com.mongodb.DB monger.collection/update (collection.clj:310)
repl =>
repl =>
repl => (clojure.repl/pst *e)
ClassCastException clojure.lang.Var$Unbound cannot be cast to com.mongodb.DB
monger.collection/update (collection.clj:310)
bkell.run.run-ring/eval2254 (NO_SOURCE_FILE:46)
clojure.lang.Compiler.eval (Compiler.java:6406)
clojure.lang.Compiler.eval (Compiler.java:6372)
clojure.core/eval (core.clj:2745)
clojure.main/repl/read-eval-print--6016 (main.clj:244)
clojure.main/repl/fn--6021 (main.clj:265)
clojure.main/repl (main.clj:265)
user/eval27/acc--3869--auto----30/fn--32 (NO_SOURCE_FILE:1)
java.lang.Thread.run (Thread.java:619)
Had anyone come across this and solved it?
Thanks

Answer 1

You have a three part question, with some inconsistencies and holes in the description. So here is my best guess, hope that it is close.
I can get all three to work given schema matched to your update requests, see test/core.clj below for complete details.
First part: Yes, you can push to the child-collection of the 3rd parent, exactly as you have written.
Second part: You want to move your "$where" clause into the criteria, and use $ in the objNew.
Third part: Yes, your basic update works for me below, exactly as you have written.
The output of "lein test" follows at the bottom. All the best to you in your endeavors.
test/core.clj
(ns free-11749-clojure-subdoc.test.core
(:use [free-11749-clojure-subdoc.core])
(:use [clojure.test])
(:require [monger.core :as mg] [monger.collection :as mgcol] [monger.query])
(:use [monger.operators])
(:import [org.bson.types ObjectId] [com.mongodb DB WriteConcern]))
(deftest monger-sub-document
(mg/connect!)
(mg/set-db! (mg/get-db "test"))
(def mycollection "free11749")
;; first part
(mgcol/remove mycollection)
(is (= 0 (mgcol/count mycollection)))
(def doc1 {
:my-criteria-key "my-criteria-value"
:parent [
{ :child-collection [ "cc0" ] }
{ :child-collection [ "cc1" ] }
{ :child-collection [ "cc2" ] }
{ :child-collection [ "cc3" ] }
{ :child-collection [ "cc4" ] }
]
}
)
(mgcol/insert mycollection doc1)
(is (= 1 (mgcol/count mycollection)))
(mgcol/update mycollection { :my-criteria-key "my-criteria-value" } { $push { "parent.3.child-collection" "fubar" }} )
(def mymap1 (first (mgcol/find-maps mycollection { :my-criteria-key "my-criteria-value" })))
(is (= "fubar" (peek (:child-collection (get (:parent mymap1) 3)))))
(prn (mgcol/find-maps mycollection { :my-criteria-key "my-criteria-value" }))
;; second part
(mgcol/remove mycollection)
(is (= 0 (mgcol/count mycollection)))
(def doc2 {
:doc-criteria-key "doc-criteria-value"
:parent [
{ :child { :lastname [ "Alias" ] } }
{ :child { :lastname [ "Smith" ] } }
{ :child { :lastname [ "Jones" ] } }
]
}
)
(mgcol/insert mycollection doc2)
(is (= 1 (mgcol/count mycollection)))
(mgcol/update mycollection { :doc-criteria-key "doc-criteria-value" "parent.child.lastname" "Smith"} { $push { :parent.$.child.lastname "fubar" } } )
(def mymap2 (first (mgcol/find-maps mycollection { :doc-criteria-key "doc-criteria-value" })))
(is (= "fubar" (peek (:lastname (:child (get (:parent mymap2) 1))))))
(prn (mgcol/find-maps mycollection { :doc-criteria-key "doc-criteria-value" }))
;; third part
(mgcol/remove "fubar")
(is (= 0 (mgcol/count "fubar")))
(def doc3 {
:owner "fubar#gmail.com"
:content [
{ :content [ "cc0" ] }
{ :content [ "cc1" ] }
{ :content [ "cc2" ] }
]
}
)
(mgcol/insert "fubar" doc3)
(is (= 1 (mgcol/count "fubar")))
(mgcol/update "fubar" { :owner "fubar#gmail.com" } { $push { "content.1.content" { "fu" "bar" } } } )
(def mymap3 (first (mgcol/find-maps "fubar" { :owner "fubar#gmail.com" })))
(is (= { :fu "bar" } (peek (:content (get (:content mymap3) 1)))))
(prn (mgcol/find-maps "fubar" { :owner "fubar#gmail.com" }))
)
lein test
Testing free-11749-clojure-subdoc.test.core
({:_id #<ObjectId 4fb3e98447281968f7d42cac>, :my-criteria-key "my-criteria-value", :parent [{:child-collection ["cc0"]} {:child-collection ["cc1"]} {:child-collection ["cc2"]} {:child-collection ["cc3" "fubar"]} {:child-collection ["cc4"]}]})
({:_id #<ObjectId 4fb3e98447281968f7d42cad>, :doc-criteria-key "doc-criteria-value", :parent [{:child {:lastname ["Alias"]}} {:child {:lastname ["Smith" "fubar"]}} {:child {:lastname ["Jones"]}}]})
({:_id #<ObjectId 4fb3e98447281968f7d42cae>, :content [{:content ["cc0"]} {:content ["cc1" {:fu "bar"}]} {:content ["cc2"]}], :owner "fubar#gmail.com"})
Ran 1 tests containing 9 assertions.
0 failures, 0 errors.