I have a collection of the form
{ id : 1,
data: [ [ { name : "alice" }, { name : "bob" } ],
[ { name : "dan" }, { name : "rob" } ] ] }
and the structure of the array has meaning. How would I update the first element ([0][0]) and set name = "alex". I've seen many questions addressing how to update array elements that match a query but not specific elements. To be clear, after the update, the record should look like this:
{ id : 1,
data: [ [ { name : "alex" }, { name : "bob" } ],
[ { name : "dan" }, { name : "rob" } ] ] }
Assuming, you have created the structure with some purpose, which ideally becomes tougher to query, you could update it by specifying the index explicitly:
db.collection.update({"id":1},{$set:{"data.0.0.name":"alex"}})
If we don't have a fixed position and is known at runtime or Dynamic
then this approach works perfectly
var setObject = {};
setObject["board."+ x +"."+ y] = player;
gamesColl.update({_id: realId},{
$set:setObject
}, function(err,doc){
console.log(err,doc);
});
you can go further!!
if you want to paste indexes as a variable use string template like this
db.collection.update({"id":1},{$set:{[`data.${index}.${index}.name`]:"alex"}})
Related
I have the following document structure in a MongoDB collection :
{
"A" : [ {
"B" : [ { ... } ]
} ]
}
I'd like to update this to :
{
"A" : [ {
"B" : [ { ... } ],
"x" : [],
"y" : { ... }
} ]
}
In other words, I want the "x" and "y" fields to be added to the first element of the "A" array without loosing "B".
Ok as there is only one object in A array you could simply do as below :
Sample Collection Data :
{
"_id" : ObjectId("5e7c3cadc16b5679b4aeec26"),
A:[
{
B: [{ abc: 1 }]
}
]
}
Query :
/** Insert new fields into 'A' array's first object by index 0 */
db.collection.updateOne(
{ "_id" : ObjectId("5e7c3f77c16b5679b4af4caf") },
{ $set: { "A.0.x": [] , "A.0.y" : {abcInY :1 }} }
)
Output :
{
"_id" : ObjectId("5e7c3cadc16b5679b4aeec26"),
"A" : [
{
"B" : [
{
"abc" : 1
}
],
"x" : [],
"y" : {
"abcInY" : 1.0
}
}
]
}
Or Using positional operator $ :
db.collection.updateOne(
{ _id: ObjectId("5e7c3cadc16b5679b4aeec26") , 'A': {$exists : true}},
{ $set: { "A.$.x": [] , "A.$.y" : {abcInY :1 }} }
)
Note : Result will be the same, but functionally when positional operator is used fields x & y are inserted to first object of A array only when A field exists in that documents, if not this positional query would not insert anything (Optionally you can check A is an array condition as well if needed). But when you do updates using index 0 as like in first query if A doesn't exist in document then update would create an A field which is an object & insert fields inside it (Which might cause data inconsistency across docs with two types of A field) - Check below result of 1st query when A doesn't exists.
{
"_id" : ObjectId("5e7c3f77c16b5679b4af4caf"),
"noA" : 1,
"A" : {
"0" : {
"x" : [],
"y" : {
"abcInY" : 1.0
}
}
}
}
However, I think I was able to get anothe#whoami Thanks for the suggestion, I think your first solution should work. However, I think I was able to get another solution to this though I'm not sure if its better or worse (performance wise?) than what you have here. My solution is:
db.coll.update( { "_id" : ObjectId("5e7c4eb3a74cce7fd94a3fe7") }, [ { "$addFields" : { "A" : { "x" : [ 1, 2, 3 ], "y" : { "abc" } } } } ] )
The issue with this is that if "A" has more than one array entry then this will update all elements under "A" which is not something I want. Just out of curiosity is there a way of limiting this solution to only the first entry in "A"?
Followup Question
Thanks #4J41 for your spot on resolution. Along the same lines, I'd also like to validate one other thing.
I have a mongo document that contains an array of Strings, and I need to convert this particular array of strings into an array of object containing a key-value pair. Below is my curent appraoch to it.
Mongo Record:
Same mongo record in my initial question below.
Current Query:
templateAttributes.find({platform:"V1"}).map(function(c){
//instantiate a new array
var optionsArray = [];
for (var i=0;i< c['available']['Community']['attributes']['type']['values'].length; i++){
optionsArray[i] = {}; // creates a new object
optionsArray[i].label = c['available']['Community']['attributes']['type']['values'][i];
optionsArray[i].value = c['available']['Community']['attributes']['type']['values'][i];
}
return optionsArray;
})[0];
Result:
[{label:"well-known", value:"well-known"},
{label:"simple", value:"simple"},
{label:"complex", value:"complex"}]
Is my approach efficient enough, or is there a way to optimize the above query to get the same desired result?
Initial Question
I have a mongo document like below:
{
"_id" : ObjectId("57e3720836e36f63695a2ef2"),
"platform" : "A1",
"available" : {
"Community" : {
"attributes" : {
"type" : {
"values" : [
"well-known",
"simple",
"complex"
],
"defaultValue" : "well-known"
},
[......]
}
I'm trying to query the DB and retrieve only the value of defaultValue field.
I tried:
db.templateAttributes.find(
{ platform: "A1" },
{ "available.Community.attributes.type.defaultValue": 1 }
)
as well as
db.templateAttributes.findOne(
{ platform: "A1" },
{ "available.Community.attributes.type.defaultValue": 1 }
)
But they both seem to retrieve the entire object hirarchy like below:
{
"_id" : ObjectId("57e3720836e36f63695a2ef2"),
"available" : {
"Community" : {
"attributes" : {
"type" : {
"defaultValue" : "well-known"
}
}
}
}
}
The only way I could get it to work was with find and map function, but it seems to be convoluted a bit.
Does anyone have a simpler way to get this result?
db.templateAttributes.find(
{ platform: "A1" },
{ "available.Community.attributes.type.defaultValue": 1 }
).map(function(c){
return c['available']['Community']['attributes']['type']['defaultValue']
})[0]
Output
well-known
You could try the following.
Using find:
db.templateAttributes.find({ platform: "A1" }, { "available.Community.attributes.type.defaultValue": 1 }).toArray()[0]['available']['Community']['attributes']['type']['defaultValue']
Using findOne:
db.templateAttributes.findOne({ platform: "A1" }, { "available.Community.attributes.type.defaultValue": 1 })['available']['Community']['attributes']['type']['defaultValue']
Using aggregation:
db.templateAttributes.aggregate([
{"$match":{platform:"A1"}},
{"$project": {_id:0, default:"$available.Community.attributes.type.defaultValue"}}
]).toArray()[0].default
Output:
well-known
Edit: Answering the updated question: Please use aggregation here.
db.templateAttributes.aggregate([
{"$match":{platform:"A1"}}, {"$unwind": "$available.Community.attributes.type.values"},
{$group: {"_id": null, "val":{"$push":{label:"$available.Community.attributes.type.values",
value:"$available.Community.attributes.type.values"}}}}
]).toArray()[0].val
Output:
[
{
"label" : "well-known",
"value" : "well-known"
},
{
"label" : "simple",
"value" : "simple"
},
{
"label" : "complex",
"value" : "complex"
}
]
In MongoDB, I'm trying to write a query to add elements from an array to an existing document, but instead of adding the elements as objects:
property: ObjectID(xxx)
the elements are getting added as just
ObjectID(xxx)
Forgive me if I get the terminology wrong. I'm completely new to MongoDB; I normally only work with relational databases. How do I properly add these new elements?
I have a collection called auctions which has two fields: ID and properties. Properties is an array of objects named property. Here's an example with two auction documents:
** I changed the object IDs to make them easier to reference in our discussion
Collection db.auctions
{
"_id" : ObjectId("abc"),
"properties" : [
{
"property" : ObjectId("prop1")
},
{
"property" : ObjectId("prop2")
},
{
"property" : ObjectId("prop3")
}]
}
{
"_id" : ObjectId("def"),
"properties" : [
{
"property" : ObjectId("prop97")
},
{
"property" : ObjectId("prop98")
}]
}
I want to add 3 new properties to auction "abc". How do I do this?
Here's is what I tried:
I have an array of properties that looks like this:
Array PropsToAdd
[
ObjectId("prop4"),
ObjectId("prop5"),
ObjectId("prop6")
]
I wrote an update query to push these properties into the properties array in auctions:
db.auctions.update(
{"_id": "abc"}
,
{ $push: { properties: { $each: PropsToAdd } } }
);
This query gave the result below. Notice that instead of adding elements named property with a value from my array, it's just added my values from my array. I obviously need to add that "property" part, but how do I do that?
Collection db.auctions (_id "abc" only)
{
"_id" : ObjectId("abc"),
"properties" : [
{
"property" : ObjectId("prop1")
},
{
"property" : ObjectId("prop2")
},
{
"property" : ObjectId("prop3")
},
ObjectId("prop4"),
ObjectId("prop5"),
ObjectId("prop6"),
ObjectId("prop7")]
}
The result I'm looking for is this:
Collection db.auctions (_id "abc" only)
{
"_id" : ObjectId("abc"),
"properties" : [
{
"property" : ObjectId("prop1")
},
{
"property" : ObjectId("prop2")
},
{
"property" : ObjectId("prop3")
},
{
"property" : ObjectId("prop4")
},
{
"property" : ObjectId("prop5")
},
{
"property" : ObjectId("prop6")
}
}
Here is some further information on that array of properties I'm adding. I get it from running these queries. Perhaps one of them needs changed?
This query gets an array of current properties:
var oldActiveProperties = db.properties.distinct( "saleNumber", { "active": true, "auction": ObjectId("abc") } );
Then those results are used to find properties in the new file that weren't in the old file:
var PropsToAdd = db.newProperties.distinct(
"_id"
, { "saleNumber": { "$nin": oldActiveProperties }, "active": true}
);
The resulting array is what I need to add to the auctions collection.
Use the JavaScript's native map() method to map the array into an array of documents. The following shows this:
var PropsToAdd = db.newProperties.distinct("_id",
{ "saleNumber": { "$nin": oldActiveProperties }, "active": true}
).map(function (p) { return { property: p }; });
db.auctions.update(
{"_id": "abc"},
{ $push: { "properties": { "$each": PropsToAdd } } }
);
I'm using Mongoose and have a schema like this:
var chat = new mongoose.Schema({
chatId : String,
members : [{
id : String,
name : String
}]
});
Suppose I have two chat document like this
{
chatId : 'Edcjjb',
members : [
{
id : 'a1',
name : 'aaa'
},
{
id : 'b1',
name : 'bbb'
}
]
}
{
chatId : 'Fxcjjb',
members : [
{
id : 'a1',
name : 'aaa'
},
{
id : 'b1',
name : 'bbb'
},
{
id : 'c1',
name : 'ccc'
}
]
}
I want to find all those documents which have only specfied members Id.
For example, if I specify a1 and b1
then only the first document should be retrieved as the second document contains id c1 as well.
And if I specifiy a1,b1,c1
then only second document should be specified.
Please tell me how to do this in mongoose
You can specify a clause on the array size, like
{ members : { $size : 2 } } in your first example and
{ members : { $size : 3 } } in the second one.
Can that work for you?
EDIT: I should also mention that the other part of the query should be
{ "members.id": { $all: [ "a1" , "b1" ] } }
and, for the second example,
{ "members.id": { $all: [ "a1" , "b1", "c1" ] } }
I have a weird problem with MongoDB (2.0.2) map reduce.
So, the story goes like this:
I have Ad model (look for model source extract below) and I need to group up to n ads per category in order to have a nice ordered listing I can later use to do more interesting things.
# encoding: utf-8
class Ad
include Mongoid::Document
cache
include Mongoid::Timestamps
field :title
field :slug, :unique => true
def self.aggregate_latest_active_per_category
map = "function () {
emit( this.category, { id: this._id });
}"
reduce = "function ( key, value ) {
return { ads:v };
}"
self.collection.map_reduce(map, reduce, { :out => "categories"} )
end
All fun and games up until now.
What I expect is to get a result in a form which resembles (mongo shell for db.categories.findOne() ):
{
"_id" : "category_name",
"value" : {
"ads" : [
{
"id" : ObjectId("4f2970e9e815f825a30014ab")
},
{
"id" : ObjectId("4f2970e9e815f825a30014b0")
},
{
"id" : ObjectId("4f2970e9e815f825a30014b6")
},
{
"id" : ObjectId("4f2970e9e815f825a30014b8")
},
{
"id" : ObjectId("4f2970e9e815f825a30014bd")
},
{
"id" : ObjectId("4f2970e9e815f825a30014c1")
},
{
"id" : ObjectId("4f2970e9e815f825a30014ca")
},
// ... and it goes on and on
]
}
}
Actually, it would be even better if I could get value to contain only array but MongoDB complains about not supporting that yet, but, with later use of finalize function, that is not a big problem I want to ask about.
Now, back to problem. What actually happens when I do map reduce is that it spits out something like :
{
"_id" : "category_name",
"value" : {
"ads" : [
{
"ads" : [
{
"ads" : [
{
"ads" : [
{
"ads" : [
{
"id" : ObjectId("4f2970d8e815f825a3000011")
},
{
"id" : ObjectId("4f2970d8e815f825a3000017")
},
{
"id" : ObjectId("4f2970d8e815f825a3000019")
},
{
"id" : ObjectId("4f2970d8e815f825a3000022")
},
// ... on and on and on
... and while I could probably work out a way to use this it just doesn't look like something I should get.
So, my questions (finally) are:
Am I doing something wrong and what is it?
I there something wrong with MongoDB map reduce (I mean besides all the usual things when compared to hadoop)?
Yes, you're doing it wrong. Inputs and outputs of map and reduce should be uniform. Because they are meant to be executed in parallel, and reduce might be run over partially reduced results. Try these functions:
var map = function() {
emit(this.category, {ads: [this._id]});
};
var reduce = function(key, values) {
var result = {ads: []};
values.forEach(function(v) {
v.ads.forEach(function(a) {
result.ads.push(a)
});
});
return result;
}
This should produce documents like:
{_id: category, value: {ads: [ObjectId("4f2970d8e815f825a3000011"),
ObjectId("4f2970d8e815f825a3000019"),
...]}}