CODEWITHSUNDEEP
mongodb
Leonardo Minati
Leonardo Minati

Reputation: 360

How do i check with a MongoDB query if a property in an object exists?

I'm building a simple query for my MongoDB Collection. The model looks like this:

{
    a: [],
    user: {
        email: String,
        name: String,
        surname: String
    }
}

What I need to get from the query are all the documents that have 'a' as non-empty array and the 'user.email' set. My query is:

Document.find({
        a: {
            $exists: true,
            $not: {
                $size: 0
            }
        },
        user: {
            $exists: true,
            'email': {
                $exists: true
            }
        }
    })

The problem is when i perform the query, my server returns a 500 Error saying:

{
    "error": {
        "name": "MongoError",
        "message": "unknown operator: email",
        "waitedMS": 0,
        "ok": 0,
        "errmsg": "unknown operator: email",
        "code": 2
    }
}

Where am I going wrong? Can anyone help me with this? Thank you!

Upvotes: 2

Views: 3985

Answers (1)

vladzam
vladzam

Reputation: 5908

Because of the way you structured your query, the MongoDB engine tries parsing the email keyword as an operator on the user field.

If you want to check if a nested attribute is defined on a document, you can use the dot notation:

Document.find({
        a: {
            $exists: true,
            $not: {
                $size: 0
            }
        },
        "user.email": {
            $exists: true
        }
    })

Upvotes: 4

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