CODEWITHSUNDEEP
pythonmongodb
gleb1783
gleb1783

Reputation: 461

MongoDB: How to determine is specific value does not exist

I can only find examples to find if specific Keys do not exist.

I have specific documents in my MongoDB instance that have fields like this:

        "actions" : [
            {
                    "date" : "2015-03-09T15:28:03Z",
                    "reason" : "",
                    "begin_date" : "2015-03-09T15:28:03Z",
                    "end_date" : "2015-03-09T15:28:03Z",
                    "action_type" : "Block",
                    "performed_date" : "2015-03-09T15:28:03Z",
                    "active" : "on",
            },
            {
                    "date" : "2015-03-09T15:28:03Z",
                    "reason" : "",
                    "begin_date" : "2015-03-09T15:28:03Z",
                    "end_date" : "2015-03-09T15:28:03Z",
                    "action_type" : "Alert",
                    "performed_date" : "2015-03-09T15:28:03Z",
                    "active" : "on",
            },
            {
                    "date" : "2015-03-09T15:28:03Z",
                    "reason" : "None",
                    "begin_date" : "2015-03-09T15:28:03Z",
                    "end_date" : "2015-03-09T15:28:03Z",
                    "action_type" : "History",
                    "performed_date" : "2015-03-09T15:28:03Z",
                    "active" : "on",
            }
    ],

Now, I am trying to generate a query to return all records where the "action_type": "History" does not exist.

I know the $exists operator can tell me if the "action_type" key doesn't exist, but I can't find any examples to tell me where I can specify what value doesn't exist.

In my head I want to say it's something like this (but obviously this doesn't work):

db.collection.find({ "actions":{"$elemMatch":{"action_type": "History"}} : { '$exists': false} } )

Hopefully this is a lot easier than I am making it out to be.

Upvotes: 3

Views: 2664

Answers (2)

Pierre
Pierre

Reputation: 6237

This should work:

db.collection.find({"actions.action_type": {"$ne": "History"}})

Upvotes: 3

Pseudonymous
Pseudonymous

Reputation: 884

Are you essentially looking to check if a value is not something? i.e. the key will always exist but you want matches where the value is not "history".

If so, there's the Not Equals operator:

http://docs.mongodb.org/manual/reference/operator/query/ne/

Upvotes: 1

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