I have an 'users' collection. I store id's of users I follow in 'following' field.
{
"_id": {
"$oid": "5eab360253ec352e3cc791d6"
},
"email": "koray#gmail.com",
"password": "81dc9bdb52d04dc20036dbd8313ed055",
"following": ["5ea8879dfc286e1154a866cb", "5ea8879dfc286e1154a866c"],
"posts": [{
"head": "deneme header",
"body": "deneme body",
"is_private": false
}]
}
I want to get posts of users I follow as well as posts belogs to me but can't manage to pull it off.
You can use $lookup with custom pipeline and fetch documents from the same collection:
db.collection.aggregate([
{ $match: { _id: "5eab360253ec352e3cc791d6" } },
{
$lookup: {
from: "collection",
let: { following_users: "$following" },
pipeline: [
{ $match: { $expr: { $in: [ "$_id", "$$following_users" ] } } },
{ $project: { posts: 1 } }
],
as: "following_posts"
}
}
])
Mongo Playground
I'm having some problem to write a query to return a triple nested value from a document. The documents I'm using are structured like this
{
"areaname": "name1",
"places": [
{
"placename": "place1",
"objects": [
{
"objname": "obj1",
"tags": [
"tag1",
"tag2"
]
},
{
"objname": "obj2",
"tags": [
"tag6",
"tag7"
]
}
]
},
{
"placename": "place2",
"objects": [
{
"objname": "obj45",
"tags": [
"tag46",
"tag34"
]
},
{
"objname": "obj77",
"tags": [
"tag56",
"tag11"
]
}
]
}
]
}
It is quite simple actually but I can't find a solution to a simple query like:
"return the objname of the object that contains tag1 inside their tag"
So for the give document if I use "tag1" as a parameter it is expected for the query to return "obj1"
It should give me the same result if I use "tag2" as a parameter
Other example: using "tag56" it should return only "obj77"
Right now i have no problem returning the whole document using the dot-notation or top level field such as areaname or others
db.users.find( {"places.objects.tags":"tag1"}, { areaname: 1, _id:0 } )
Is this even possible?
Keeping it simple:
[
{
"$match" : {
"places.objects.tags" : "tag1"
}
},
{
"$unwind" : "$places"
},
{
"$unwind" : "$places.objects"
},
{
"$match" : {
"places.objects.tags" : "tag1"
}
},
{
"$group" : {
"_id" : "$_id",
"obj_names" : {
"$push" : "$places.objects.objname"
}
}
}
],
You should add any other fields you want to keep to the group stage,
this can also be done without the double $unwind stage but i choose this for read-ability.
Here is the sample JSON
Sample JSON:
[
{
"_id": "123456789",
"YEAR": "2019",
"VERSION": "2019.Version",
"QUESTION_GROUPS": [
{
"QUESTIONS": [
{
"QUESTION_NAME": "STATE_CODE",
"QUESTION_VALUE": "MH"
},
{
"QUESTION_NAME": "COUNTY_NAME",
"QUESTION_VALUE": "IN"
}
]
},
{
"QUESTIONS": [
{
"QUESTION_NAME": "STATE_CODE",
"QUESTION_VALUE": "UP"
},
{
"QUESTION_NAME": "COUNTY_NAME",
"QUESTION_VALUE": "IN"
}
]
}
]
}
]
Query that am using :
db.collection.find({},
{
"QUESTION_GROUPS.QUESTIONS.QUESTION_NAME": "STATE_CODE"
})
My requirement is retrive all QUESTION_VALUE whose QUESTION_NAME is equals to STATE_CODE.
Thanks in Advance.
If I get you well, What you are trying to do is something like:
db.collection.find(
{
"QUESTION_GROUPS.QUESTIONS.QUESTION_NAME": "STATE_CODE"
},
{
"QUESTION_GROUPS.QUESTIONS.QUESTION_VALUE": 1
})
Attention: you will get ALL the "QUESTION_VALUE" for ANY document which has a QUESTION_GROUPS.QUESTIONS.QUESTION_NAME with that value.
Attention 2: You will get also the _Id. It is by default.
In case you would like to skip those issues, you may need to use Aggregations, and unwind the "QUESTION_GROUPS"-> "QUESTIONS". This way you can skip both the irrelevant results, and the _id field.
It sounds like you want to unwind the arrays and grab only the question values back
Try this
db.collection.aggregate([
{
$unwind: "$QUESTION_GROUPS"
},
{
$unwind: "$QUESTION_GROUPS.QUESTIONS"
},
{
$match: {
"QUESTION_GROUPS.QUESTIONS.QUESTION_NAME": "STATE_CODE"
}
},
{
$project: {
"QUESTION_GROUPS.QUESTIONS.QUESTION_VALUE": 1
}
}
])
I have a MongoDB that is structured as below:
[
{
"subject_id": "1",
"name": "Maria",
"dob": "1/1/00",
"gender": "F",
"visits": {
"1/1/18": {
"date_entered": "1/2/18",
"entered_by": "Sally"
},
"1/2/18": {
"date_entered": "1/2/18",
"entered_by": "Tim",
}
},
"samples": {
"XXX123": {
"collected_by": "Sally",
"collection_date": "1/3/18"
}
}
},
{
"subject_id": "2",
"name": "Bob",
"dob": "1/2/00",
"gender": "M",
"visits": {
"1/3/18": {
"date_entered": "1/4/18",
"entered_by": "Tim"
}
},
"samples": {
"YYY456": {
"collected_by": "Sally",
"collection_date": "1/5/18"
},
"ZZZ789": {
"collected_by": "Tim",
"collection_date": "1/6/18"
},
"AAA123": {
"collected_by": "Sally",
"collection_date": "1/7/18"
}
}
}
]
If I wanted to query the database to find all samples collected by Sally or all visits entered by Tim, what would be the best way of doing that?
I'm new to MongoDB and my attempts with various regex's haven't produced results. Any advice would be greatly appreciated.
I first used project on the required fields to use objectToArray followed by unwind to create separate records for array created in project.
The results are then filtered using match.
This works for the data provided in the question -
db.so.aggregate([
{$project: {visits: {$objectToArray: "$visits"}, samples: {$objectToArray: "$samples"}}},
{$unwind: "$visits"},
{$unwind: "$samples"},
{ $match: {
$or : [
{ "visits.v.entered_by" : "Tim" },
{ "samples.v.collected_by" : "Sally" }
]
}
}
])
The examples here don't go nearly far enough in explaining how to produce a more complicated structure...
If I want to end up with something like:
{
"data": {
"type": "mobile_screens",
"id": "1",
"attributes": {
"title": "Watch"
},
"relationships": {
"mobile_screen_components": {
"data": [
{
"id": "1_1",
"type": "mobile_screen_components"
},
{
"id": "1_2",
"type": "mobile_screen_components"
},
...
]
}
}
},
"included": [
{
"id": "1_1",
"type": "mobile_screen_components",
"attributes": {
"title": "Featured Playlist",
"display_type": "shelf"
},
"relationships": {
"playlist": {
"data": {
"id": "938973798001",
"type": "playlists"
}
}
}
},
{
"id": "938973798001",
"type": "playlists",
"relationships": {
"videos": {
"data": [
{
"id": "5536725488001",
"type": "videos"
},
{
"id": "5535943875001",
"type": "videos"
}
]
}
}
},
{
"id": "5536725488001",
"type": "videos",
"attributes": {
"duration": 78321,
"live_stream": false,
"thumbnail": {
"width": 1280,
"url":
"http://xxx.jpg?pubId=694940094001",
"height": 720
},
"last_published_date": "2017-08-09T18:26:04.899Z",
"streams": [
{
"url":
"http://xxx.m3u8",
"mime_type": "MP4"
}
],
"last_modified_date": "2017-08-09T18:26:27.621Z",
"description": "xxx",
"fn__media_tags": [
"weather",
"personality"
],
"created_date": "2017-08-09T18:23:16.830Z",
"title": "NOAA predicts most active hurricane season since 2010",
"fn__tve_authentication_required": false
}
},
...,
]
}
what is the most simple data structure and serializer I can set up?
I get stumped after something like:
const mobile_screen_components = responses.map((currentValue, index) => {
id[`id_${index}`];
});
const dataSet = {
id: 1,
title: 'Watch',
mobile_screen_components,
};
const ScreenSerializer = new JSONAPISerializer('mobile_screens', {
attributes: ['title', 'mobile_screen_components'],
mobile_screen_components: {
ref: 'id',
}
});
Which only gives me:
{
"data": {
"type": "mobile_screens",
"id": "1",
"attributes": { "title": "Watch" },
"relationships": {
"mobile-screen-components": {
"data": [
{ "type": "mobile_screen_components", "id": "1_0" },
{ "type": "mobile_screen_components", "id": "1_1" },
{ "type": "mobile_screen_components", "id": "1_2" },
{ "type": "mobile_screen_components", "id": "1_3" },
{ "type": "mobile_screen_components", "id": "1_4" },
{ "type": "mobile_screen_components", "id": "1_5" }
]
}
}
}
}
I have no idea how to get the "included" sibling to "data." etc.
So, the question is:
what is the most simple data structure and serializer I can set up?
Below is the simplest object that can be converted to JSON similar to JSON in the question using jsonapi-serializer:
let dataSet = {
id: '1',
title: 'Watch',
mobile_screen_components: [
{
id: '1_1',
title: 'Featured Playlists',
display_type: 'shelf',
playlists: {
id: 938973798001,
videos: [
{
id: 5536725488001,
duration: 78321,
live_stream: false
},
{
id: 5535943875001,
duration: 52621,
live_stream: true
}
]
}
}
]
};
To serialize this object to JSON API, I used the following code:
let json = new JSONAPISerializer('mobile_screen', {
attributes: ['id', 'title', 'mobile_screen_components'],
mobile_screen_components: {
ref: 'id',
attributes: ['id', 'title', 'display_type', 'playlists'],
playlists: {
ref: 'id',
attributes: ['id', 'videos'],
videos: {
ref: 'id',
attributes: ['id', 'duration', 'live_stream']
}
}
}
}).serialize(dataSet);
console.log(JSON.stringify(json, null, 2));
The first parameter of JSONAPISerializer constructor is the resource type.
The second parameter is the serialization options.
Each level of the options equals to the level of the nested object in serialized object.
ref - if present, it's considered as a relationships.
attributes - an array of attributes to show.
Introduction
First of all we have to understand the JSON API document data structure
[0.1] Refering to the top level (object root keys) :
A document MUST contain at least one of the following top-level
members:
data: the document’s “primary data”
errors: an array of error objects
meta: a meta object that contains non-standard meta-information.
A document MAY contain any of these top-level members:
jsonapi: an object describing the server’s implementation
links: a links object related to the primary data.
included: an array of resource objects that are related to the primary data and/or each other (“included resources”).
[0.2]
The document’s “primary data” is a representation of the resource or
collection of resources targeted by a request.
Primary data MUST be either:
a single resource identifier object, or
null, for requests that target single resources
an array of resource identifier
objects, or an empty array ([]), for reqs. that target
collections
Example
The following primary data is a single resource object:
{
"data": {
"type": "articles",
"id": "1",
"attributes": {
// ... this article's attributes
},
"relationships": {
// ... this article's relationships
}
}
}
In the (jsonapi-serializer) documentation : Available serialization option (opts argument)
So in order to add the included (top-level member) I performed the following test :
var JsonApiSerializer = require('jsonapi-serializer').Serializer;
const DATASET = {
id:23,title:'Lifestyle',slug:'lifestyle',
subcategories: [
{description:'Practices for becoming 31337.',id:1337,title:'Elite'},
{description:'Practices for health.',id:69,title:'Vitality'}
]
}
const TEMPLATE = {
topLevelLinks:{self:'http://example.com'},
dataLinks:{self:function(collection){return 'http://example.com/'+collection.id}},
attributes:['title','slug','subcategories'],
subcategories:{ref:'id',attributes:['id','title','description']}
}
let SERIALIZER = new JsonApiSerializer('pratices', DATASET, TEMPLATE)
console.log(SERIALIZER)
With the following output :
{ links: { self: 'http://example.com' },
included:
[ { type: 'subcategories', id: '1337', attributes: [Object] },
{ type: 'subcategories', id: '69', attributes: [Object] } ],
data:
{ type: 'pratices',
id: '23',
links: { self: 'http://example.com/23' },
attributes: { title: 'Lifestyle', slug: 'lifestyle' },
relationships: { subcategories: [Object] } } }
As you may observe, the included is correctly populated.
NOTE : If you need more help with your dataSet, edit your question with the original data.