How to add a sub document to sub document array in MongoDB - mongodb

Question

I have a collection in mogodb like this:
{
"_id" : ObjectId("5393006538efaae30ec2d458"),
"userName" : "shiva",
"userUnderApiKey" : 123456,
"groups" : [
{
"groupName" : "Default",
"groupMembers" : [ ]
}
]
}
I want to add a new group in the groups array as sub document, like the below
{
"_id" : ObjectId("5393006538efaae30ec2d458"),
"userName" : "shiva",
"userUnderApiKey" : 123456,
"groups" : [
{
"groupName" : "Default",
"groupMembers" : [ ]
},
{
"groupName" : "Family",
"groupMembers" : [ ]
}
]
}
How to insert new sub document in the array of sub documents.Any help would be appriciated

Answer 1

To add a new member to the array you just use $push as you normally would:
db.collection.update(
{ "_id": ObjectId("5393006538efaae30ec2d458") },
{
"$push": {
"groups": {
"groupName" : "Family",
"groupMembers" : [ ]
}
}
}
)
If you then wanted to add members to the array that member contains then you need to match the element you want to add to:
db.collection.update(
{
"_id": ObjectId("5393006538efaae30ec2d458"),
"groups.groupName" : "Family",
},
{
"$push": {
"groups.$.groupMembers" : "bill"
}
}
)

Answer 2

I think you would be interested in $push
The $push operator appends a specified value to an array.
and $addToSet
The $addToSet operator adds a value to an array only if the value is not already in the array. If the value is in the array, $addToSet does not modify the array.
you can find examples in the documents above. It would be something like:
db.collection.update({
_id: ObjectId("5393006538efaae30ec2d458")
}, {
$push: {
groups: {
"groupName": "Family",
"groupMembers": []
}
}
});

Answer 3

SampleModel:
{
"Name":String,
"brandid": {
type: Schema.ObjectId,
ref: 'BrandList.BrandItems',
}
}
BrandModel:
{
"BrandName" : String,
"BrandItems": [{
"KG": Number,
"_id" : {type: Schema.ObjectId}
}]
}
How to refered subdocument array Object id to another model..and also how to use populate for this "brandid"..
Pls give me some solutin to solve this problem....