Question

I have a document in MongoDB which holds some meta info like the date updated and the _id, and an array of addresses.

{
    "_id": {
        "$oid": "4e73a30466ca1a1f56000001"
    },
    "updated": 1316215062,
    "address": [
        {
            "street": "Rotenturmstrasse 8",
            "postcode": "1020",
            "phone": "Vienna",
            "altitude": -1,
            "geolocation": [
                "11.367464",
                "47.204876"
            ]
        }
    ]
}

Now there could be multiple addresses. I am creating an object for an address which needs to be updated and saving it to the database. This is what the new object to be inserted looks like:

new_object = {
    :_id=>BSON::ObjectId('4e73a30466ca1a1f56000001'), 
    :updated=>1316215099, 
    :address=>[
        nil, 
        nil, 
        {
            :street=>"Reumannplatz 8", 
            :postcode=>"1020", 
            :phone=>"Vienna", 
            :altitude=>-1, 
            :geolocation=>[
                "12.367464", 
                "48.204876"
            ]
        }
    ]
}

Upon calling db.venues.save(new_object) what I would like the document to end up looking like is:

{
    :_id=>BSON::ObjectId('4e73a30466ca1a1f56000001'), 
    :updated=>1316215099, 
    :address=>[         {
            "street": "Rotenturmstrasse 8",
            "postcode": "1020",
            "phone": "Vienna",
            "altitude": -1,
            "geolocation": [
                "11.367464",
                "47.204876"
            ]
        },

        nil,

        {
            :street=>"Reumannplatz 8", 
            :postcode=>"1020", 
            :phone=>"Vienna", 
            :altitude=>-1, 
            :geolocation=>[
                "12.367464", 
                "48.204876"
            ]
        }
    ]
}

Instead it overwrites the entire array and ends up like this:

{
    :_id=>BSON::ObjectId('4e73a30466ca1a1f56000001'), 
    :updated=>1316215099, 
    :address=>[
        nil, 
        nil, 
        {
            :street=>"Reumannplatz 8", 
            :postcode=>"1020", 
            :phone=>"Vienna", 
            :altitude=>-1, 
            :geolocation=>[
                "12.367464", 
                "48.204876"
            ]
        }
    ]
}

What’s the way to do it? I am trying to avoid multiple queries. Would it make things easier if the address array in the database was a hash instead?

Answer 1

To alter the data use mongodb modifiers.

In this case, you want to $push a new value to the array.