Is this possible? I have a collection C, with an array of attributes A1. Each attribute has an array of subattributes A2.
How can I add a subdocument to a specific C.A1 subdocument ?
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A before and after example document illustrating what you're looking for would be helpful.JohnnyHK– JohnnyHK2012-10-08 16:42:45 +00:00Commented Oct 8, 2012 at 16:42
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3 Answers
Here is an example.
db.docs.insert({_id: 1, A1: [{A2: [1, 2, 3]}, {A2: [4, 5, 6]}]})
If you know the index of the subdocument you want to insert, you can use dot notation with the index (starting from 0) in the middle:
db.docs.update({_id: 1}, {$addToSet: {'A1.0.A2': 9}})
This results in:
{
"A1" : [
{
"A2" : [
1,
2,
3,
9
]
},
{
"A2" : [
4,
5,
6
]
}
],
"_id" : 1
}
1 Comment
jcollum
"If you know the index of the subdocument you want to insert, " -- how would you know the index if you're inserting it?
Yes, this is possible. If you post an example I can show you more specifically what the update query would look like. But here's a shot:
db.c.update({ A1: value }, { $addToSet: { "A1.$.A2": "some value" }})
I haven't actually tried this (I'm not in front of a Mongo instance right now) and I'm going off memory, but that should get you pretty close.
Comments
Yes, $push can be used to do the same. Try below given code.
db.c.update({ A1: value }, { $push: { "A1.$.A2": num }});
Comments
