Only get sub subarray that matches query in MongooseJs - mongodb

I'm new to mongodb and mongoose and I'm having trouble just getting a sub sub array.
My data is like this:
[
{_id : ...,
name : 'Category name1',
products : [
{
code : 'zxcv'
name : 'T-Shirt 1',
items : [
{code:'zxcv', size : 'S'}
{code:'zxcv', size : 'M'}
{code:'zxcv', size : 'L'}
{code:'zxcv', size : 'XL'}
]
},
{
code : 'qwerty'
name : 'T-Shirt 2',
items : [
{code:'qwerty', size : 'S'}
{code:'qwerty', size : 'M'}
{code:'qwerty', size : 'L'}
{code:'qwerty', size : 'XL'}
]
}
]
},
{_id : ...,
name : 'Category name2',
products : [ ... ]
}
]
I want to get just the products where the code = 'zxcv'
If I do:
ProductGroup.find({'products.code' : 'zxcv'},function(err, products){})
I get all of the first product category - not just the products that have code = 'zxcv'

I figured it out. Since I spend hours searching for an answer and couldn't find one, maybe this will help another noob with the same problem:
To get just the products that match:
ProductGroup.find({'products.code' : 'zxcv'},'products.code.$.items', function(err, products){})

Related

How to search nearest place in array object in mongodb

the mongodb document 'contents' is
{
"_id" : ObjectId("57bd1ff410ea3c38386b9194"),
"name" : "4Fingers",
"locations" : [
{
"id" : "locations1",
"address" : "68 Orchard Rd, #B1-07 Plaza Singapura, Plaza Singapura, Singapura 238839",
"phone" : "+65 6338 0631",
"openhours" : "Sunday-Thursday: 11am - 10pm \nFriday/Saturday/Eve of PH*: 11am - 11pm",
"loc" : [
"1.300626",
"103.845061"
]
}
],
"comments" : [ ],
"modified" : 1472271793525,
"created" : 1472012276724,
"createdby" : "Admin",
"modifiedby" : "Admin",
"createdipaddress" : "localhost",
"modifiedipaddress" : null,
"types" : "Restaurant",
"category" : "FoodAndBeverages",
"logo" : "logo4Fingers.png",
"tags" : "western, chicken, restaurant, food, beverages"
}
I want to find the nearest place to my location that i get from HTML5 navigation. How do i query it? Data should be sorted in near to far order.
Thank you.
To query mongodb geospatial data first you need a geo spatial index on your location field.
Your location field is a string, it needs to be a numeric type, you need to update your data accordingly.
Create your index on numerical location data:
db.collection.createIndex( { "locations.loc" : "2d" });
Query:
var projection = {"locations.loc":1};
var query = {"locations.loc": {"$near":[1.300626, 103.845061], "$maxDistance": 0.5}};
db.collection.find(query, projection).pretty();
//result:
{
"_id" : ObjectId("57bd1ff410ea3c38386b9194"),
"locations" : [
{
"loc" : [
1.300626,
103.845061
]
}
]
}
var query2 = {"locations.loc": {"$near":[2.300626, 103.845061], "$maxDistance": 0.5}};
db.collection.find(query2, projection).pretty();
//result:
{}
The query result will be sorted always, with nearest as first document.
Thanks Sergiu Zaharie.
It's working.
Then how can i returned all the field instead of returning this field only.
{
"_id" : ObjectId("57bd1ff410ea3c38386b9194"),
"locations" : [
{
"loc" : [
103.845061,
1.300626
]
}
]
}
//edit
Solved.
i just clear the projection then it work like charm.
Thank you.

Sorting on GeoWithin MongoDB

So I made this query:
db.zips.find( { loc : { $geoWithin : { $box :[ [ -90 , 30 ] , [ -80 , 40 ] ] } } } )
And here is one (out of many) outputs:
{ "city" : "APISON", "loc" : [ -85.016404, 35.014926 ], "pop" : 1614, "state" : "TN", "_id" : "37302" }
My question is how would i be able to sort this by population and limit it to 10? When i try {$sort{pop:1}} i get errors it doesn't know pop, also when i add {$limit:10} at the end or my query it doesn't limit it to 10 entries but only shows me the last column.
Any help would be greatly appreciated!
db.zips.find({loc:{$geoWithin:{$box:[[-90,30],[-80,40]]}}}).sort({pop:1}).limit(10)

Is it possible to query MongoDB, using ONLY Array([x][y[x][z]]) Approach? NOT knowing Elements' Content?

This is the first of 7 test/example documents, in collection "SoManySins."
{
"_id" : ObjectId("51671bb6a6a02d7812000018"),
"Treats" : "Sin1 = Gluttony",
"Sin1" : "Gluttony",
"Favourited" : "YES",
"RecentActivity" : "YES",
"GoAgain?" : "YeaSure."
}
I would like to be able to query to retrieve any info in any position,
just by referring to the position. The following document,
{
"_id" : ObjectId("51671bb6a6a02d7812000018"),
"Sin1" : "Gluttony",
"?????????" : "??????",
"RecentActivity" : "YES",
"GoAgain?" : "YeaSure."
}
One could retrieve whatever might be in the 3rd key~value
pair. Why should one have to know ahead of time what the
data is, in the key? If one has the same structure for the
collection, who needs to know? This way, you can get
double the efficiency? Like having a whole lot of mailboxes,
and your app's users supply the key and the value; your app
just queries the dbs' documents' arrays' positions.
Clara? finally? I hope?
The sample document you've provided is not saved as an array in BSON:
{
"_id" : ObjectId("51671bb6a6a02d7812000018"),
"Sin1" : "Gluttony",
"?????????" : "??????",
"RecentActivity" : "YES",
"GoAgain?" : "YeaSure."
}
Depending on the MongoDB driver you are using, the fields here are typically represented in your application code as an associative array or hash. These data structures are not order-preserving so you cannot assume that the 3rd field in a given document will correspond to the same field in another document (or even that the same field ordering will be consistent on multiple fetches). You need to reference the field by name.
If you instead use an array for your fields, you can refer by position or select a subset of the array using the $slice projection.
Example document with an array of fields:
{
"_id" : ObjectId("51671bb6a6a02d7812000018"),
"fields": [
{ "Sin1" : "Gluttony" },
{ "?????????" : "??????" },
{ "RecentActivity" : "YES" },
{ "GoAgain?" : "YeaSure." }
]
}
.. and query to find the second element of the fields array (a $slice with skip 1, limit 1):
db.SoManySins.find({}, { fields: { $slice: [1,1]} })
{
"_id" : ObjectId("51671bb6a6a02d7812000018"),
"fields" : [
{
"?????????" : "??????"
}
]
}
This is one way to Query and get back data when you may not
know what the data is, but you know the structure of the data:
examples in Mongo Shell, and in PHP
// the basics, setup:
$dbhost = 'localhost'; $dbname = 'test';
$m = new Mongo("mongodb://$dbhost");
$db = $m->$dbname;
$CursorFerWrites = $db->NEWthang;
// defining a set of data, creating a document with PHP:
$TheFieldGenerator = array( 'FieldxExp' => array(
array('Doc1 K1'=>'Val A1','Doc1 K2'=>'ValA2','Doc1 K3'=>'Val A3'),
array('Doc2 K1'=>'V1','Doc2 K2'=>'V2','Doc2 K3'=>'V3' ) ) ) ;
// then write it to MongoDB:
$CursorFerWrites->save($TheFieldGenerator);
NOTE : In the Shell : This produces the same Document:
> db.NEWthang.insert({"FieldxExp" : [
{"Doc1 K1":"Val A1","Doc1 K2":"Val A2","Doc1 K3":"Val A3"},
{"Doc2 K1":"V1", "Doc2 K2":"V2","Doc2 K3":"V3"}
]
})
#
Now, some mongodb Shell syntax:
> db.NEWthang.find().pretty()
{
"_id" : ObjectId("516c4053baa133464d36e836"),
"FieldxExp" : [
{
"Doc1 K1" : "Val A1",
"Doc1 K2" : "Val A2",
"Doc1 K3" : "Val A3"
},
{
"Doc2 K1" : "V1",
"Doc2 K2" : "V2",
"Doc2 K3" : "V3"
}
]
}
> db.NEWthang.find({}, { "FieldxExp" : { $slice: [1,1]} } ).pretty()
{
"_id" : ObjectId("516c4053baa133464d36e836"),
"FieldxExp" : [
{
"Doc2 K1" : "V1",
"Doc2 K2" : "V2",
"Doc2 K3" : "V3"
}
]
}
> db.NEWthang.find({}, { "FieldxExp" : { $slice: [0,1]} } ).pretty()
{
"_id" : ObjectId("516c4053baa133464d36e836"),
"FieldxExp" : [
{
"Doc1 K1" : "Val A1",
"Doc1 K2" : "Val A2",
"Doc1 K3" : "Val A3"
}
]
}
Finally, how about write the Query in some PHP ::
// these will be for building the MongoCursor:
$myEmptyArray = array();
$TheProjectionCriteria = array('FieldxExp'=> array('$slice' => array(1,1)));
// which gets set up here:
$CursorNEWthang1 = new MongoCollection($db, 'NEWthang');
// and now ready to make the Query/read:
$ReadomgomgPls=$CursorNEWthang1->find($myEmptyArray,$TheProjectionCriteria);
and the second document will be printed out:
foreach ($ReadomgomgPls as $somekey=>$AxMongoDBxDocFromCollection) {
var_dump($AxMongoDBxDocFromCollection);echo '<br />';
}
Hope this is helpful for a few folks.

Map reduce in mongodb

I have mongo documents in this format.
{"_id" : 1,"Summary" : {...},"Examples" : [{"_id" : 353,"CategoryId" : 4},{"_id" : 239,"CategoryId" : 28}, ... ]}
{"_id" : 2,"Summary" : {...},"Examples" : [{"_id" : 312,"CategoryId" : 2},{"_id" : 121,"CategoryId" : 12}, ... ]}
How can I map/reduce them to get a hash like:
{ [ result[categoryId] : count_of_examples , .....] }
I.e. count of examples of each category.
I have 30 categories at all, all specified in Categories collection.
If you can use 2.1 (dev version of upcoming release 2.2) then you can use Aggregation Framework and it would look something like this:
db.collection.aggregate( [
{$project:{"CatId":"$Examples.CategoryId","_id":0}},
{$unwind:"$CatId"},
{$group:{_id:"$CatId","num":{$sum:1} } },
{$project:{CategoryId:"$_id",NumberOfExamples:"$num",_id:0 }}
] );
The first step projects the subfield of Examples (CategoryId) into a top level field of a document (not necessary but helps with readability), then we unwind the array of examples which creates a separate document for each array value of CatId, we do a "group by" and count them (I assume each instance of CategoryId is one example, right?) and last we use projection again to relabel the fields and make the result look like this:
"result" : [
{
"CategoryId" : 12,
"NumberOfExamples" : 1
},
{
"CategoryId" : 2,
"NumberOfExamples" : 1
},
{
"CategoryId" : 28,
"NumberOfExamples" : 1
},
{
"CategoryId" : 4,
"NumberOfExamples" : 1
}
],
"ok" : 1

MongoDB Update Deep Array

I have the following object in my mongo database named music.
I want to update where the genre is Grunge
The band name is Nirvana
The album name is Nevermind
The track order is 1
and change the track's name to "Smells Like Teen Spirit!".
I've tried playing with the positional operator, but can't quite
figure this out.
{
genre : "Grunge",
bands : [ {
name : "Nirvana",
albums : [ {
name : "Nevermind",
tracks : [ {
name : "Smell Like Teen Spirit",
order : 1,
duration : 301
},
{
name : "In Bloom",
order : 2,
duration : 254
} ]
},
{
name : "In Utero",
tracks : [ {
name : "Server the Servants",
order : 1,
duration : 216
},
{
name : "Scentless Apprentice",
order : 2,
duration : 254
} ]
} ]
},
{
name : "Karma++ : A Nirvina Tribute Band",
albums : [ {
name : "Nevermind",
tracks : [ {
name : "Smell Like Teen Spirit",
order : 1,
duration : 301
},
{
name : "In Bloom",
order : 2,
duration : 254
} ]
},
{
name : "In Utero",
tracks : [ {
name : "Server the Servants",
order : 1,
duration : 216
},
{
name : "Scentless Apprentice",
order : 2,
duration : 254
} ]
} ]
} ]
}
Unfortunately, at present it is only possible to use a single "$" positional per update. This limits the update to a single embedded array, similar to the example in the documentation: http://www.mongodb.org/display/DOCS/Updating#Updating-The%24positionaloperator
(From your post, it looks like you have already found this, but I have included the link for the benefit of any other users reading this post.)
In order to make the update, you will have to know the position of two out of the following three: The position of the band in the "bands" array, the position of the album in the albums array, or the position of the track in the "tracks" array.
There is a feature request for this functionality, and it is slated for version 2.3.0 (although this is subject to change).
https://jira.mongodb.org/browse/SERVER-831 "Positional Operator Matching Nested Arrays"
For the time being, you will have to know the position of the sub documents in two out of the three arrays:
db.music.update({genre : "Grunge", "bands.name" : "Nirvana"}, {$set:{"bands.$.albums.0.tracks.0.name":"Smells Like Teen Spirit!"}})
db.music.update({genre : "Grunge", "bands.0.albums.name" : "Nevermind"}, {$set:{"bands.0.albums.$.tracks.0.name":"Smells Like Teen Spirit!"}})
or
db.music.update({genre : "Grunge", "bands.0.albums.0.tracks.order" : 1}, {$set:{"bands.0.albums.0.tracks.$.name":"Smells Like Teen Spirit!"}})