Update object with given ID embed in array without restructuring Mongo database

Question

I've got the following document named "clients" which includes id, name and list of projects (array of objects):

{
    "_id": {
        "$oid": "572225d997bb651819f379f7"
    },
    "name": "ppg",
    "projects": [
        {
            "name": "aaa",
            "job_description": "",
            "projectID": 20
        },
        {
            "name": "bbbb",
            "job_description": "",
            "projectID": 21
        }
    ]
}

I would like to update "job_description" of project with given "projectID" like this:

module.exports.saveJobDesc = function(client, idOfProject, textProvided) {
    db.clients.update({ name: client}, 
    { $set: {'projects.0.job_description': textProvided }});
};

But instead of hardcoded index "0" of array I want to find specific project using "projectID". Is there a way to achieve this without changing the structure of collection and/or document?

What about using findOne to get the client object first and then iterating his projects manually? — Gershon Papi
– Gershon Papi, Commented Apr 28, 2016 at 20:50

Ankit Aneja · Accepted Answer · 2016-04-29 16:00:20Z

1

If you want to update the "job_description" where name="ppg" and project_id=20 then you can use below mongo query:-

db.clients.update({ "name":"ppg","projects.projectID":20 },{$set: {"projects.$.job_description": "abcd"}})

Please let me know if any thing else is required

answered Apr 29, 2016 at 16:00

Ankit Aneja

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Comments

achuth · Accepted Answer · 2016-04-29 05:02:51Z

You cannot update multiple array elements in single update operation, instead you can update one by one which takes time depends upon number of elements in array and number of such documents in collection. see New operator to update all matching items in an array

   db.test2.find().forEach( function(doc) {
    var projects = doc.projects;
    for(var i=0;i<projects.length;i++){
        var project = projects[i];
        if(project.projectID == 20){
            var field = "projects."+i+".job_description";
            var query = {};
            query[field] = "textasdsd";
            db.test2.update({ _id: doc._id},{ $set:query});
        }
}
})

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