My first adventure into Mongo. Please save me some time by answering the following. This is the schema.
"_id" : 1,
"FullName" : "Full Name",
"Email" : "email#email.com",
"FacebookId" : NumberLong(0),
"LastModified" : ISODate("2012-04-11T09:26:10.955Z"),
"Connections" : [{
"_id" : 7,
"FullName" : "Fuller name",
"Email" : "connections#email.com",
"FacebookId" : NumberLong(0),
"LastModified" : ISODate("0001-01-01T00:00:00Z")
},
....
Given an id of a single top user, i'd like to return all of the Emails in the Connections array, and preferably, just the emails. What's the querystring? Much obliged!
You can't get only values from the sub-objects in MongoDB.
If you do a query like this:
db.test.find({"_id": 1}, {"Connections.Email":1});
you will get this kind of response:
{
"_id": 1,
"Connections" : [ {"Email":"connections#email.com"},
{"Email":"foo#example.com"} ]
}
This is the closest you can get with a simple query and field selection from MongoDB.
You can then filter out the e-mails values in your code with a simple foreach.
Related
Following is example of table in mongodb, I have multiple records for companies like this, which I need help with.
I wanted to query the below table wherein using value from company I should be able to retrieve the name of all the cars.
"vehicles" : [
{
"source" : "jeep",
"tag" : [
{
"company" : "toyota",
"name" : "fortuner"
},
{
"company" : "rangerover",
"name" : "discovery"
]
}
]
Thanks...
try this :
db.vehicles.find({tag: {$elemMatch: {company:'toyota'}}}).pretty();
read more here : https://docs.mongodb.com/manual/reference/operator/query/elemMatch/
I found a question similar to mine regarding updating a document if a certain field does not exist. But in the question, it is not an array of documents like what I have
{
"_id" : ObjectId("5a5f814487c320156094c144"),
"sender_id" : "123",
"iso_number" : "ABC-DEF-123",
"subject" : "Sample Memo",
"content" : "This is a sample memorandum sent through postman.",
"recipients" : [
{
"faculty_number" : 222,
"_id" : ObjectId("5a5f814487c320156094c146"),
"status" : "Sent"
},
{
"faculty_number" : 111,
"_id" : ObjectId("5a5f814487c320156094c145"),
"status" : "Sent"
}
],
"memo_created" : ISODate("2018-01-17T17:00:52.104Z"),
"__v" : 0
}
I'm trying to attach a memo_seen to recipient with faculty_number 111, I'm using the query.
db.getCollection('memos').update({"_id": id, "recipients.faculty_number": faculty_number, "recipients.$.memo_seen": {$exists: false}}, {$set: {"recipients.$.memo_seen": timestamp}})
The timestamp should not update when I repeat the query. Can someone help me out? Been stuck for quite some time now.
I'm new to mongodb and javascript, and have been reading the manual, but I can't seem to put the pieces together to solve the following problem.. I was wondering if you can kindly help.
I have two collections "places" and "reviews".
One document in "places" collection is as follows:
{
"_id" : "004571a7-afe4-4124-996e-b6ec779db494",
"name" : "wakawaka place",
"address" : {
"address" : "12 ad avenue",
"city" : "New York",
},
"review" : [
{
"id" : "i32347",
"review_list" : [
"r123456",
"r123457"
],
}
]
}
The "review" array can be empty for some documents.
And in the "reviews" collection, every document in the collection represents a review:
{
"_id" : ObjectId("53c913689c8e91a5a9c4047f"),
"user_id" : "useridhere",
"review_id" : "r123456",
"attraction_id" : "i32347",
"content" : "review content here"
}
What I would like to achieve is, for each place that has reviews, get the content of each review from the "review" collection and store them together in another new collection.
I'd be grateful for any suggestions on how to go about this.
Thanks
I've got this structure of document, saved in MongoDB 2.6.1, running on Linux:
{
"_id" : "1",
"name" : "Level0",
"childs" : [
{
"id" : "2",
"name" : "Level1",
"childs" : [
{
"id" : "3",
"name" : "Level2",
"childs" : [
{
"id" : "4",
"name" : "Level3-1",
},
{
"id" : "5",
"name" : "Level3-2",
}
]
}
...
Every Element got his childs and every child-element got his own childs until the technical end.
Now I want to Query my MongoDB with something like:
db.categories.find({'childs':{$elemMatch:{$all:['Level19-23']}}})
This Query dont work by the way.
What is a good query to get my elements?
I dont know anything about the children or parents, I've got only the name of the element, and I need the element with all his children.
Anyone got an advise for me, the MongoDB Newbe? :)
Thanks in advance!
I have two collection as bellow products has reference of user. i search product by name & in return i want combine output of product and user using map reduce method
user collection
{
"_id" : ObjectId("52ac5dd1fb670c2007000000"),
"company" : {
"about" : "This is textile machinery dealer",
"contactAddress" : [{
"address" : "abcd",
"city" : "52ac4bc6fb670c1007000000",
"zipcode" : "39as46as80"
},{
"address" : "abcd",
"city" : "52ac4bc6fb670c1007000000",
"zipcode" : "39as46as80"
}],
"fax" : "58784868",
"mainProducts" : "ads,asd,asd",
"mobileNumber" : "9537236588",
"name" : "krishna steels",
}
"user" : ObjectId("52ac4eb7fb670c0c07000000")
}
product colletion
{
"_id" : ObjectId("52ac5722fb670cf806000002"),
"category" : "52a2a9cc48a508b80e00001d",
"deliveryTime" : "10 days after received the ",
"price" : {
"minPrice" : "2000",
"maxPrice" : "3000",
"perUnit" : "5288ac6f7c104203e0976851",
"currency" : "INR"
},
"productName" : "New Mobile Solar Charger with Carabiner",
"rejectReason" : "",
"status" : 1,
"user" : ObjectId("52ac4eb7fb670c0c07000000")
}
This cannot be done. Mongo support Map Reduce only on one collection. You could try to fetch and merge in a java collection. Couple of days back I solved a similar problem using java collection.
Click to see similar response about joins and multi collection not supported in mongo.
This can be done using two map reduces.
You run your first MR and then you reduce out the second MR onto the results of the first.
You shouldn't do this though. JOINs are not designed to be done through MR, in fact it sounds like you are trying to do this MR with inline output which in itself is a very bad idea.
MRs are not designed to run inline to the application.
You would be better off doing the JOIN else where.