I have the following schema into my DB:
{ name: 'AFG',
documents: [
{ name: 'doc1',
templates: [
{ name: 'templ1',
lastModified: <Date>},
...]
},
...]
}
I am trying to make a query to look for the template with name 'templ1'. If I find it, I have to compare the last modification date with another and update the value. If I don't find it, I have to push it into the array.
I have tried to do it with the following query:
Country.findOne({name : countrySelected, documents : {$elemMatch: {name: documentSelected}}, 'documents.templates' : {$elemMatch: {name: templateSelected}}}, function(err, templateFound){...}
But I get the following error:
MongoError: cannot use the part (documents of documents.templates) to traverse the element ({documents: [ { name: "Passport", templates: [] }, { name: "Visa", templates: [] }, { name: "Driver's Licence", templates: [] }, { name: "Id Card", templates: [] }, { name: "Other", templates: [] } ]})
Someone knows how can I do it? Thanks!!
You have to use the $in operator to search in arrays.
Country.findOne({
name : countrySelected,
documents: {
$elemMatch: {
$and: [{
name: {
$in: documentSelected //<-- must be array like ['doc1']
}
}, {
'templates.name': {
$in: documentSelected //<-- must be array like ['tmpl1']
}
}]
}
}
}, function(err, templateFound){
//do something with err and templateFound
});
To update the LastModified date you need to update it in the callback function and save the document.
See this answer for nested array updates
Related
I have a database of a the employees of a company that looks like this:
{
_id: 7698,
name: 'Blake',
job: 'manager',
manager: 7839,
hired: ISODate("1981-05-01T00:00:00.000Z"),
salary: 2850,
department: {name: 'Sales', location: 'Chicago'},
missions: [
{company: 'Mac Donald', location: 'Chicago'},
{company: 'IBM', location: 'Chicago'}
]
}
I have an exercise in which I need to write the MongoDb command that returns all them employees who did all their missions in Chicago. I struggle with the all because I cannot find a way to check that all the locations of the missions array are equal to 'Chicago'.
I was thinking about doing it in two time: first find the total number of missions the employee has and then compare it to the number of mission he has in Chicago (that how I would do in SQL I guess). But I cannot found the number of mission the employee did in Chicago. Here is what I tried:
db.employees.aggregate([
{
$match: { "missions": { $exists: true } }
},
{
$project: {
name: 1,
nbMissionsChicago: {
$sum: {
$cond: [
{
$eq: [{
$getField: {
field: { $literal: "$location" },
input: "$missions"
}
}, "Chicago"]
}, 1, 0
]
}
}
}
}
])
Here is the result :
{ _id: 7698, name: 'Blake', nbMissionsChicago: 0 }
{ _id: 7782, name: 'Clark', nbMissionsChicago: 0 }
{ _id: 8000, name: 'Smith', nbMissionsChicago: 0 }
{ _id: 7902, name: 'Ford', nbMissionsChicago: 0 }
{ _id: 7499, name: 'Allen', nbMissionsChicago: 0 }
{ _id: 7654, name: 'Martin', nbMissionsChicago: 0 }
{ _id: 7900, name: 'James', nbMissionsChicago: 0 }
{ _id: 7369, name: 'Smith', nbMissionsChicago: 0 }
First of all, is there a better method to check that all the locations of the missions array respect the condition? And why does this commands returns only 0 ?
Thanks!
If all you need is the agents who had all their missions in "Chicago" then you don't need an aggregation pipeline for it, specifically the approach of filtering the array as part of the aggregation can't utilize an index and will make performance even worse.
A simple query should suffice here:
db.collection.find({
$and: [
{
"missions": {
$exists: true
}
},
{
"missions.location": {
$not: {
$gt: "Chicago"
}
}
},
{
"missions.location": {
$not: {
$lt: "Chicago"
}
}
}
]
})
Mongo Playground
This way we can build an index on the missions field and utilize it properly, any documents with a different value other then "Chigaco" will not match as they will fail the $gt or $lt comparion.
Note that an empty array also matches the condition, you can change the generic "missions" exists condition key into "missions.0": {$exists: true}, this will also require at least one mission.
You are unable to get the correct result as it is not the correct way to iterate the element in an array field.
Instead, you need to work with $size operator to get the size of an array and the $filter operator to filter the document.
Updated: You can directly compare the filtered array with the original array.
db.employees.aggregate([
{
$match: {
"missions": {
$exists: true
}
}
},
{
$project: {
name: 1,
nbMissionsChicago: {
$eq: [
{
$filter: {
input: "$missions",
cond: {
$eq: [
"$$this.location",
"Chicago"
]
}
}
},
"$missions"
]
}
}
}
])
Demo # Mongo Playground
I have an object that has an array of page objects and each page object has an array of questions.
Ex object:
{
Id: 1,
UserId: 14,
Deleted: false,
Collaborators: [],
Title: "Awesome",
Pages: [{
Id: 1,
Title: 'Jank',
Questions: [
{ Id: 1, Content: 'Ask me about it' },
{ Id: 2, Content: 'Ask me about it again' }
]
}, {
Id: 2,
Title: 'Janker',
Questions: [
{ Id: 1, Content: 'Tell me about it' },
{ Id: 2, Content: 'Tell me about it again' }
]
}]
}
What I am trying to do is to get a count of all the questions for the entire bas object. I am not sure how to do that. I have tried to use aggregate and $sum the total questions and then do another function to $sum those all together to get a total for the entire object. Unfortunately my $sum is not working like I thought it would.
Ex code (nodejs):
var getQuestionCount = function(id) {
var cursor = mongo.collection('surveys').aggregate([{
$match: {
$or: [{
"UserId": id
}, {
"Collaborators": {
$in: [id]
}
}]
}
}, {
$match: {
"Deleted": false
}
}, {
$unwind: "$Pages"
},
{ $group: { _id: null, number: { $sum: "$Pages.Questions" } } }
], function(err, result) {
//This log just gives me [object Object], [object Object]
console.log('q count ' + result);
});
}
Any idea how to do this? My end result from the example object above would ideally return 4 as the question count for the whole object.
I'd try following shell query.
db.collection.aggregate([
// filter out unwanted documents.
{$match:{Id: 1}},
// Unwind Pages collection to access Questions array
{$unwind:"$Pages"},
// Count items in Questions array
{$project:{count: {$size:"$Pages.Questions"}}},
// Finally sum items previously counted.
{$group:{_id:"$_id", total: {$sum: "$count"}}}
])
Based on your sample document, it should return correct count of Questions.
{
"_id" : ObjectId("57723bb8c10c41c41ff4897c"),
"total" : NumberInt(4)
}
I have an collection with an array of objects in it (I just put some fields out of it, the schema is working perfectly).
Collection Contacts:
title: {
type: String,
label: "Title",
max: 200
},
adresses: {
type: [Object],
optional: true
},
"adresses.$.id": {
type: String,
label: "ID"
},
"adresses.$.street": {
type: String,
label: "street",
decimal: true,
optional: true
}
When i do a :
db.contacts.findOne({_id: "59gXADmH9GLNDjELo"}, {adresses: {$elemMatch:
{id: "xpdYRKGGjHJLnCevM"}}});
on Mongo DB console, it returns:
{
"_id" : "59gXADmH9GLNDjELo",
"adresses" : [
{
"id" : "xpdYRKGGjHJLnCevM",
"street" : "FakeStreet123"
}
]
}
Like I want it - just 1 element of the array back.
When I do the same on Meteor (Browser Console):
Contacts.findOne({_id: "59gXADmH9GLNDjELo"}, {adresses: {$elemMatch:
{id: "xpdYRKGGjHJLnCevM"}}});
I get all elements of the array back. How to solve this? I want the same result as I got in Mongo DB.
You could use the ._find() underscore method to retrieve just the document you want:
var doc = Contacts.findOne(
{_id: "59gXADmH9GLNDjELo"},
{adresses: {
$elemMatch: {id: "xpdYRKGGjHJLnCevM"}
}
}),
address = _.find(doc.adresses, function(address) {
return address._id === "xpdYRKGGjHJLnCevM"
});
Lets say that I have the following document in the books collection:
{
_id:0 ,
item: "TBD",
stock: 0,
info: { publisher: "1111", pages: 430 },
tags: [ "technology", "computer" ],
ratings: [ { _id:id1, by: "ijk", rating: 4 }, {_id:id2 by: "lmn", rating: 5 } ],
reorder: false
}
I would like to update the value of ratings[k].rating and all I know is the id of the collection and the _id of the objects existing in the array ratings.
The tutorial of mongoDB has the following example that uses the position of the object inside the array but I suppose that if the update can only be done by knowing the position, this means that I firstly have to find the position and then proceed with the update? Can I do the update with only one call and if so how I can do that?
db.books.update(
{ _id: 1 },
{
$inc: { stock: 5 },
$set: {
item: "ABC123",
"info.publisher": "2222",
tags: [ "software" ],
"ratings.1": { by: "xyz", rating: 3 }
}
}
)
Sorry for late answer; I think this is what you want to do with mongoose.
Books.findOneAndUpdate({
_id: 1,
'ratings._id': id1
},
{
$set: {
'ratings.$.rating' : 3
}
}, function(err, book){
// Response
});
Positional operator may help you:
db.books.update(
// find book by `book_id` with `rating_id` specified
{ "_id": book_id, "ratings._id": rating_id },
// set new `value` for that rating
{ $set: { 'ratings.$.rating': value }}
);
$ will save position of matched document.
I have a Mongodb document that contains an an array that is deeply imbedded inside the document. In one of my action, I would like to return the entire document but filter out the elements of that array that don't match that criteria.
Here is some simplified data:
{
id: 123 ,
vehicles : [
{name: 'Mercedes', listed: true},
{name: 'Nissan', listed: false},
...
]
}
So, in this example I want the entire document but I want the vehicles array to only have objects that have the listed property set to true.
Solutions
Ideally, I'm looking for a solution using mongo's queries (e.g. `$unwind, $elemMatch, etc...) but I'm also using mongoose so solution that uses Mongoose is OK.
You could use aggregation framework like this:
db.test312.aggregate(
{$unwind:"$vehicles"},
{$match:{"vehicles.name":"Nissan"}},
{$group:{_id:"$_id",vehicles:{$push:"$vehicles"}}}
)
You can use $addToSet on the group after unwinding and matching by listed equals true.
Sample shell query:
db.collection.aggregate([
{
$unwind: "$vehicles"
},
{
$match: {
"vehicles.listed": {
$eq: true
}
}
},
{
$group: {
_id: "$id",
vehicles: {
"$addToSet": {
name: "$vehicles.name",
listed: "$vehicles.listed"
}
}
}
},
{
$project: {
_id: 0,
id: "$_id",
vehicles: 1
}
}
]).pretty();