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I am trying to construct a Mongodb query to return a field value. My JSON looks like this:
"question" : "Global_Deployment",
"displayOrder" : 1,
"answerOptions" : {
"fieldId" : "1001",
"fieldType" : "radiobutton",
"fieldName" : "Global Deployment?",
"fieldLabel" : "Global Deployment?",
"helpText" : "Help will go here",
"emailTagFormControl" : "Global_Deployment?",
"source" : "custom",
"status" : "active",
"required" : "true",
"multiSelect" : "false",
"purgeFlag" : "false",
"enableAuditTrack" : "false",
"fields" : [],
"fieldValue" : "Yes",
"options" : [
{
"optionName" : "Yes"
},
{
"optionName" : "No"
}
],
"comments" : {
"commentId" : "C1001",
"commentDetails" : []
}
My query to reach the field with the fieldName "Global Deployment" is this:
db.getCollection('requests').find({"sections.questions.answerOptions.fieldName":"Global Deployment?"})
What I want to know is what to add to this query to return the value of "fieldValue", which is on a different line in the JSON. I am new to Mongodb. Any help would be greatly appreciated.
1) If you've multiple documents in DB with "fieldName" : "Global Deployment?", then .find() would return all the matching documents i.e; in the output what you get is an array of documents then you need to iterate through the array to get answerOptions.fieldValue for each document, Check the below scenario, as I've explained there are chances of getting multiple documents if "sections.questions.answerOptions.fieldName" is not an unique field.
db.getCollection('requests').find({"sections.questions.answerOptions.fieldName":"Global Deployment?"}, {'sections.questions.answerOptions.fieldValue':1})
Output of find :
/* 1 */
[{
"_id" : ObjectId("5d4e19826e173840500f5674"),
"answerOptions" : {
"fieldValue" : "Yes"
}
},
/* 2 */
{
"_id" : ObjectId("5d4e19826e073840500f5674"),
"answerOptions" : {}
}]
If you only need documents which has fieldValue in it then do this :
db.getCollection('requests').find({"sections.questions.answerOptions.fieldName":"Global Deployment?", 'sections.questions.answerOptions.fieldValue':{$exists: true}}, {'answerOptions.fieldValue':1})
Ok now you've array of documents then do iterate thru each to retrieve your value, check this mongoDB cursor tutorial .
2) If you think fieldName is unique across collection, then you can use .findOne() , which would exactly return one document (In case if you've multiple matching documents it would return first found doc) :
db.getCollection('requests').findOne({"sections.questions.answerOptions.fieldName":"Global Deployment?"}, {'sections.questions.answerOptions.fieldValue':1})
Output of findOne :
{
"_id" : ObjectId("5d4e19826e173840500f5674"),
"answerOptions" : {
"fieldValue" : "Yes"
}
}
If you see .find({},{}) has two arguments, second one is called projection which literally be useful if you want to retrieve only required fields in the response, By default mongoDB will return the entire document what ever you've posted in the question will be retrieved, Data in mongoDB flows as JSON's so operating will be similar to using JSON's, Here you can retrieve the required fields out of result, but for best use of network efficiency if you don't need entire document you'll only get the required fields using projection.
You can specify the second condition separated by comma. Either you are trying to filter data with $and or with $or
With simple approach:
{"sections.questions.answerOptions.fieldName":"Global Deployment?","sections.questions.answerOptions.fieldValue":"Yes" }
By using $and method:
.find(
{
$and: [
{"sections.questions.answerOptions.fieldName":"Global Deployment?"},
{"sections.questions.answerOptions.fieldValue":"Yes"}
]
}
)
Same way you can use $or method. Just replace $and with $or.
Edit:
If you want to retrieve specific value (in your case fieldValue), query would be:
db.getCollection('requests').find({
"sections.questions.answerOptions.fieldName":"Global Deployment?"
}).map(function(item){
return item.fieldValue
})
The correct answer here is the method .distinct() (docs)
In your case try it like this:
db.getCollection('requests').find({"sections.questions.answerOptions.fieldName":"Global Deployment?"}).distinct('fieldValue');
That will return only the value you want.
If you use findOne you can use dot notation.
For example, if we start with creating a collection to test using the following to get close to your sample:
db.stackOverflow.insertOne({
sections: {
questions: {
question: "Global_Deployment",
displayOrder: 1,
answerOptions: {
fieldId: "1001",
fieldType: "radiobutton",
fieldName: "Global Deployment?",
fieldLabel: "Global Deployment?",
helpText: "Help will go here",
emailTagFormControl: "Global_Deployment?",
source: "custom",
status: "active",
required: "true",
multiSelect: "false",
purgeFlag: "false",
enableAuditTrack: "false",
fields: [],
fieldValue: "Yes",
options: [
{
optionName: "Yes",
},
{
optionName: "No",
},
],
comments: {
commentId: "C1001",
commentDetails: [],
},
},
},
},
})
then, this query will return "Yes".
db.stackOverflow.findOne({}).sections.questions.answerOptions.fieldValue
In my database.collection i.e. db.blog.posts I am trying to add a key and value that itself has multiple keys and values.
Current collection:
db.blog.posts.findOne()
"title":"blog posts"
I tried using $set, $push but nothing seems to work.
This also didn't work when I tried adding single collection:
db.blog.posts.updateOne({"title":"blog posts"}, {"$set":{"comments":[{"comment":"good post", "author":"john","votes":0}]}})
Nor insertOne instead of updateOne and I even tried with:
var myEmployee=[
{"comment":"good post", "author":"john", "votes":0},
{"comment":"i thought it was too short", "author":"claire","votes":3},
{"comment":"free watches", "author":"claire","votes":-1},
];
db.blog.posts.insert(myEmployee)
This is what I want:
"title" : "A blog post",
"comments" : [
{
"name" : "joe",
"email" : "joe#example.com",
"content" : "nice post."
},
{
"name" : "bob",
"email" : "bob#example.com",
"content" : "good post."
}
]
The updateOne command you have should have created an array for comments with a single entry. If you wanted multiple entries, you can just add multiple objects to the array in the update. The $set operator will change the value of the key to what you set as the second parameter.
db['blog.posts'].updateOne({"title":"blog posts"}, {
"$set": {
"comments":[
{
"name" : "joe",
"email" : "joe#example.com",
"content" : "nice post."
},
{
"name" : "bob",
"email" : "bob#example.com",
"content" : "good post."
}
]
}
})
If you want to add additional items to the comments, this can be done with $push. The $push operator adds to the array.
db['blog.posts'].updateOne({"title":"blog posts"}, {
"$push": {
"comments": {
"comment": "good post",
"author": "john",
"votes": 0
}
}
})
Docs for $set
Docs for $push
NB the examples above are for a collection named 'blog.posts' rather than a database named 'blog' and a collection names 'posts'. Ideally, brackets should be used for the property accessor where the collection name is not a valid JavaScript identifier although the dot notation in the question still works.
I have a collection named authors with the following schema:
authors: {
_id,
firstName,
lastName,
posts: [
post 1: {...},
post 2: {...},
post 3: {
_id,
title,
content,
tags: [
tag 1: {...},
tag 2: {...},
tag 3: {
_id,
name,
description,
},
],
},
],
}
As can be seen, posts is an array of objects inside the authors collection. Each object inside this array, in turn, has tags, another array of objects. And each of these tags objects has three fields: _id, name, and description.
I'm trying to write a GraphQL mutation to update this name field on matching documents in the collection.
const updatedTagInAuthor = await Author
.updateMany({ 'posts.tags._id': args.newTagInfo._id },
{
$set: {
'posts.$.tags.$.name': args.newTagInfo.name,
'posts.$.tags.$.description': args.newTagInfo.description,
},
}, opts);
The above snippet obviously fails since MongoDB doesn't allow multiple positional elements ($) in a query. So is there any economical alternative to accomplish what I'm trying to do?
I tried the ArrayFilter method as MongoDB suggests:
const updatedTagInAuthor = await Author.update(
{},
{ $set: { 'posts.$[].tags.$[tag].name': args.newTagInfo.name } },
{ arrayFilters: [{ 'tag._id': args.newTagInfo._id }], multi: true }
);
But this throws the following error:
Cannot read property 'castForQuery' of undefined
Still confused!
These are the documents I'm updating with the kind of query I have given,
{"name" : "Steve","details" : [ {
"work" : [ {
"Company" : "Byjus",
"id" : 1,
"country" : "India"
},
{
"Company" : "Vodafone",
"id" : 2,
"country" : "UK"
}]
}]},{"name" : "Virat","details" : [ {
"work" : [ {
"Company" : "Byjus",
"id" : 1,
"country" : "India"
},
{
"Company" : "Verizon",
"id" : 3,
"country" : "US"
}]
}]}
QUERY:
db.getCollection('Users').update({"details": {"$elemMatch": {"work.id": 1}}}, {'$set': {'details.$[].work.$.Company': 'Boeing', 'details.$[].work.$.country': 'US'} }, {multi: true});
It's similar to what you asked right?
Try inserting those two Documents in a collection called User and try the above query in Mongo CONSOLE directly, not in GUI. Use the Query completely not just the $set method.
Try this,
Author.update({"posts": { "$elemMatch": { "tags.id": args.newTagInfo._id } }},
{'$set': {'posts.$[].tags.$.name': args.newTagInfo.name, 'posts.$[].tags.$.description': args.newTagInfo.description} },
{multi: true});
I should start with: I'm knew to MongoDB, and document-style databases in general.
I have a collection that looks something like this:
{
"_id" : ObjectId("554a5e72b16f31ff0894310e"),
"title" : "ABC",
"admins" : [
"personA",
"personB",
],
"email_address" : "ABC#mysite.com"
}
{
"_id" : ObjectId("554a5e72b16f31ff0894310f"),
"title" : "Junk Site",
"admins" : [
"personA",
"personB"
],
"email_address" : "garbage#mysite.com"
}
{
"_id" : ObjectId("554a5e72b16f31ff08943110"),
"title" : "Company Three Site",
"admins" : [
"personC"
"personD",
],
"email_address" : "company2plus1#mysite.com"
}
What I need to do, is append the admins list from Company One, to Company Three such that Company Three now has four admins (A, B, C, D).
I tried the following, because it seemed pretty straight forward to me - get the data from the origin and append to destination directly:
db.runCommand({
findAndModify : 'sites',
query : {'title' : 'Company Three Site'},
update : { '$addToSet' :
{'admins' :
db.projects.find({'title' : 'ABC'}, {'_id' : 0, 'admins' : 1}
}
}
})
However, this does not work correctly.
I am still trying to figure out ways I could do this directly, but questions...
1) Is this even possible by using single command, or do I need to split this up?
2) Does my train of logical thought make sense, or should I be doing this some other/easier way that is more conventional for MongoDB style databases?
db.projects.find actually returns a cursor, which you definitely don't want to add to your set. Since you know ahead of time that you will be only finding one value, you can get the properties out of the cursor specifically by using .next().admin -- but remember that this will only work with the first value returned from .find. Otherwise, I think you will have to use a loop.
$addToSet will also add the array as a whole, so instead you have to append multiple values using $each
All together:
db.runCommand({
findAndModify: 'sites',
query: {'title': 'Company Three Site'},
update: {
$addToSet: {
"admins": {
$each: db.projects.find(
{"title": "ABC"},
{"_id": 0, "admins": 1}
).next().admins
}
}
}
})
This is not possible with an atomic update. However, a workaround is to query the source collection using the find() method and use the cursor's forEach() method to iterate over the results, get the array and update the destination collection using the $addToSet operator and the $each modifier.
Let's demonstrate this with the above sample documents inserted to a test collection:
db.test.insert([
{
"title" : "ABC",
"admins" : [
"personA",
"personB"
],
"email_address" : "ABC#mysite.com"
},
{
"title" : "Junk Site",
"admins" : [
"personA",
"personB"
],
"email_address" : "garbage#mysite.com"
},
{
"title" : "Company Three Site",
"admins" : [
"personC",
"personD"
],
"email_address" : "company2plus1#mysite.com"
}
])
The following operation will add the admins array elements from company "ABC" to the company "Company Three Site" admin array:
db.test.find({"title" : "ABC"}).forEach(function (doc){
var admins = doc.admins;
db.test.update(
{"title" : "Company Three Site"},
{
"$addToSet": {
"admins": { "$each": admins }
}
},
{ "multi": true }
);
});
Querying the collection for the document with company "Company Three Site" db.collection.find({"title" : "Company Three Site"});
will yield:
/* 0 */
{
"_id" : ObjectId("554a7dc35c5e0118072dd885"),
"title" : "Company Three Site",
"admins" : [
"personC",
"personD",
"personA",
"personB"
],
"email_address" : "company2plus1#mysite.com"
}
So, what I'm trying to do is query all documents that have a City of 'Paris' and a State of 'France'. I need to do some kind of join, but I haven't been able to figure out how to construct it.
I'm using the c# driver, but I'll gladly accept help using any method.
{
"_id" : ObjectId("519b407f3c22a73a7c29269f"),
"DocumentID" : "1",
"Meta" : [{
"Name" : "City",
"Value" : "Paris",
}, {
"Name" : "State",
"Value" : "France",
}
}]
}
{
"_id" : ObjectId("519b407f3c22a73a7c29269g"),
"DocumentID" : "2",
"Meta" : [{
"Name" : "City",
"Value" : "Paris",
}, {
"Name" : "State",
"Value" : "Texas",
}
}]
}
The $elemMatch operator is used to indicate that all the conditions within it must be matched by the same array element. So (to switch to shell syntax) to match all documents which have meta city Paris you would do
db.collection.find( {Meta:{$elemMatch:{Name:"City",Value:"Paris"}}} )
This assures you won't match something which has Name: "somethingelse", Value: "Paris" somewhere in its array with a different array element matching the Name:"City".
Now, default combination for combining query conditions is "and" so you can continue adding attributes:
db.collection.find( {Meta: {
$elemMatch:{Name:"City",Value:"Paris"},
$elemMatch:{Name:"State",Value:"France"}
}
}
)
Now if you want to add another condition you keep adding it but if you want a NOT then you do it like this:
db.collection.find( {Meta: {
$elemMatch:{Name:"City",Value:"Paris"},
$elemMatch:{Name:"State",Value:"France"},
$not: {$elemMatch:{Name:"Arrondissement",Value:"Louvre"}}
}
}
)
I might be answering my own question here, but I'm new to MongoDB, so while this appears to give me the results I'm after, it might not be the optimum approach.
var result = collection.Find(
Query.And(
Query.ElemMatch("Meta", Query.EQ("Name", "City")),
Query.ElemMatch("Meta", Query.EQ("Value", "Paris")),
Query.ElemMatch("Meta", Query.EQ("Name", "State")),
Query.ElemMatch("Meta", Query.EQ("Value", "France")))
);
Which leads to a follow up - how would I get all of the documents whose 'City' is 'Paris' and 'State' is 'France' but whose 'Arrondissement' is not 'Louvre'?