MongoDB updating fields in nested array

Question

MongoDB updating fields in nested array

How can I set \"play\" to \"play photo\" in the photos array?

I only know its _id.

\"_id\": ObjectId(         


        

Answer 1

This issue has been resoved. Feature of updating fields inside nested array of objects, is available in MongoDB 3.6+ versions. Look positional operators(all and with identifier) here.

//Update all docs in collection matching photo name "play" to "play photo"
db.collectioname.update(
    {},
    { $set: { "albums.$[].photos.$[photo_field].name": "play photo" } },
    { arrayFilters: [  {"photo_field.name": "play"} ], multi: true}
);

//Update this specific doc given in question matching photo name "play" to "play photo"
db.collectioname.update(
    {"_id" : ObjectId("4f41a5c7c32810e404000000")},
    { $set: { "albums.$[].photos.$[photo_field].name": "play photo" } },
    { arrayFilters: [  {"photo_field.name": "play"} ]}
);

This is for the help of people coming here after MongoDB 3.6

Answer 2

You can't. The positional operator is only available for the first array in your document hierarchy. As such you cannot manipulate individual elements of deeper nester arrays.

It's a known issue and is scheduled for development here : https://jira.mongodb.org/browse/SERVER-831

Until that time you'll have to normalize your schema a bit I'm afraid.

Answer 3

Tonilin You Cant Update this type of array directly for this you need to find the index of that array in which you want to update like if you want to update name as play photo then you have to find the index of photos where name is play. For this I used this code like:

$m = new Mongo();
$db=$m->yourdatabase;
//testarray is my collection name
$result=$db->testarray->find();
$index='';
foreach($result as $res)
{
    if(array_key_exists("albums",$res))
    {
        foreach($res['albums'] as $ralbum)
        {
            if(array_key_exists("photos",$ralbum))
            {
                foreach($ralbum['photos'] as $k=>$rphotos)
                {
                    if(array_key_exists("name",$rphotos))
                        if($rphotos['name']=='play')
                            $index=$k;
                }
            }
        }
    }
}
//echo $index;

// Now to update this value in your database use this code...

if($index!=='')
{
    //Run like this in Shell
    //db.testarray.update({"albums.photos._id":ObjectId("4f545d1bc328103812d00000")},{'$set':{"albums.$.photos.1.name":"play132"}})
    $condition=array("albums.photos._id"=>new MongoId("4f545d1bc328103812d00000"));
    $data=array('$set'=>array("albums.$.photos.".$index.".name"=>"play photo"));
    $result=$db->testarray->update($condition,$data);
    $status=$db->Command(array('getlasterror'=>1));
    print_r($status);
}