Set same value on multiple fields

Question

I have the following document structure:

{
    ...
    timings: {
        mon: "",
        tue: "",
        wed: "",
        thu: "",
        fri: "",
        sat: "",
        sun: "",
    }
    ...
}

I want to set the value "Open 24 Hours" for all the days of the week.

Currently I am using the query:

db.collection.update({_id: ObjectId("someId")}, {$set: {"timings.mon": "Open 24 Hours"}});

And then running the same for the rest of the days of the week.

I can also set all the fields in the same query explicitly, but it's faster to just change the day and run it again.

Is there a way to set the value of multiple fields in a subdocument in a more efficient way?

UPDATE

I tried the following query, but it doesn't work:

db.collection.update({_id: ObjectId("someId")}, {$set: {"timings.$": "Open 24 Hours"}});

chridam · Accepted Answer · 2015-05-09T14:46:17.597

You could try first creating the update object where you can set the multiple fields of that object before updating the document this way:

var days = ["mon", "tue", "wed", "thu", "fri", "sat", "sun"],
    timings = {},
    query = {"_id" : ObjectId("554e12e4674dec7517e692eb")},
    update = {
        "$set": { "timings": timings }
    },
    options = {"upsert": true};

days.forEach(function (day){ timings[day] = "Open 24 Hours" });
db.collection.update(query, update, options);

Querying the collection for that document using db.collection.findOne(query) will yield:

/* 0 */
{
    "_id" : ObjectId("554e12e4674dec7517e692eb"),
    "timings" : {
        "mon" : "Open 24 Hours",
        "tue" : "Open 24 Hours",
        "wed" : "Open 24 Hours",
        "thu" : "Open 24 Hours",
        "fri" : "Open 24 Hours",
        "sat" : "Open 24 Hours",
        "sun" : "Open 24 Hours"
    }
}

-- UPDATE --

Another approach (as suggested by @Michael in the comments) is to use the JavaScript's native Object.keys() method which returns an array of a given object's own enumerable properties, in the same order as that provided by a for...in loop (the difference being that a for-in loop enumerates properties in the prototype chain as well):

> var days = Object.keys(db.collection.findOne().timings);
> print(days);
mon,tue,wed,thu,fri,sat,sun
>

And thus can be implemented as:

var days = Object.keys(db.collection.findOne().timings),
    timings = {},
    query = {"_id" : ObjectId("554e12e4674dec7517e692eb")},
    update = {
        "$set": { "timings": timings }
    },
    options = {"upsert": true};

instead of creating the `days` array manually you could do `Object.keys(db.collection.findOne().timings)` — styvane, May 09 '15 at 14:18
@Michael You are right, that's one elegant way. The approach above takes into consideration selective updates, the OP might want to update certain properties so the `days` array may be adjusted accordingly. — chridam, May 09 '15 at 14:21

Set same value on multiple fields

1 Answers1