如何在MongoDb中更新数组值

Question

$set is overtiring complete array value how to update it

                var obj = // contains some other data to update as well 
                obj.images=images;  //  updating obj with images []
                Units.update({_id: 'id', {$set: obj});

finally my mongo object must be something like this

{
"_id" : "ZhBgrNFtr2LRPkQrZ",
"sitouts" : "test",
"interiors" : "test",
"features" : "test",
"keyHolder" : "test",
"images" : [
    "1445481257465-8678-20130520_113154.jpg", ## `updated value ` ##
    "1445481257456-3-20130520_113157.jpg",
    "1445481258058-5771-20130520_113202.jpg",
    "1445481258230-9603-20130521_075648.jpg"
]

}

Answer 1

https://docs.mongodb.org/manual/reference/operator/update/push/ $push, $each, $slice. See the documentation.

Answer 2

Here are a few ways to update the images array without overwriting it:

Update a Specific Index

Units.update({_id: id}, {$set: {'images.0': obj.images[0]}})

Append a Single Value

Units.update({_id: id}, {$push: {images: obj.images[0]}})

Append Multiple Values

Units.update({_id: id}, {$push: {images: {$each: obj.images}}})