CODEWITHSUNDEEP
javascriptmongodbmongoose
Lightningz1
Lightningz1

Reputation: 63

ArrayFilter is failing to match any elements

I'm working on a simple web forum system and i've come across this problem when trying to give the users a way to post messages to a thread. Each thread is a document inside an array in a group document, and then inside each thread document is a message array which should contain message documents.

My query is:

 db.grops.update({},{$push:{"threads.$[elem].messages":"hello"}},{arrayFilters:[{"elem._id":ObjectId("602645582fa6cb13f8449057")}]})

And my group table of the db is:

{
    "_id" : ObjectId("60264286f5440e114c189212"),
    "members" : [ ],
    "name" : "Computer Science London",
    "location" : {
            "coordinates" : [
                    51.503391,
                    -0.12763
            ],
            "_id" : ObjectId("60264286f5440e114c189213"),
            "type" : "Point"
    },
    "description" : "A group for computing students to learn, talk and share!",
    "pictureURL" : "/images/computer.jpg",
    "threads" : [
            {
                    "_id" : ObjectId("602645582fa6cb13f8449057"),
                    "title" : "What is a lambda function",
                    "openingPost" : "I am reading this textbook and it mentions this thing called a lambda function, but it doesnt seem to outline what it is. Can someone help me understand?",
                    "postedBy" : "ElBarto88",
                    "updatedAt" : ISODate("2021-02-12T09:07:36.833Z"),
                    "createdAt" : ISODate("2021-02-12T09:07:36.833Z"),
                    "messages" : [ ]
            },
            {
                    "_id" : ObjectId("602645af2fa6cb13f8449058"),
                    "title" : "How do i install linux?",
                    "openingPost" : "This server assignment requires i have linux installed, how do install it?",
                    "postedBy" : "ElBarto88",
                    "updatedAt" : ISODate("2021-02-12T09:09:03.123Z"),
                    "createdAt" : ISODate("2021-02-12T09:09:03.123Z"),
                    "messages" : [ ]
            }
    ],
    "createdAt" : ISODate("2021-02-12T08:55:34.273Z"),
    "updatedAt" : ISODate("2021-02-12T09:09:03.123Z"),
    "__v" : 0
}

I can not seem to get any query to get any matches, and then push "hello" to the sub-array. I have also tried matching by {"elem.postedBy:"ElBarto88"}, to no avail. For all the queries involving arrayFilters i get back:

WriteResult({ "nMatched" : 0, "nUpserted" : 0, "nModified" : 0 })

Currently i am just testing by posting the queries directly to the mongo shell(i am using mongoose for the main application). My shell version is: v4.4.2 , and my server version (MongoDB atlas cluster) is: v4.4.3

Upvotes: 0

Views: 98

Answers (2)

Lightningz1
Lightningz1

Reputation: 63

I've been really stupid, it was a spelling mistake causing my problems. group not grop, not the code.

facepalms and closes thread quickly

Upvotes: 0

Vo Quoc Thang
Vo Quoc Thang

Reputation: 1396

I believe you can do this:

db.grops.update({"threads.$._id":ObjectId("602645582fa6cb13f8449057")},{$push:{"threads.$.messages":"hello"}})

Let me know if it doesn't work. Remember: it wil update ONLY FIRST matching element.

Upvotes: 1

Related Questions