var ConversationSchema = new Schema({
conversationName:String,
conversationID: String,
participants: [
{
Id:String
}
]
})
I'm trying to query the conversation schema to return every conversation where the participant array contain the id of the user i'm looking at. In node js please
The simplest way to query a array of subdocuments in mongo (using example given in question)
// just query here
{ 'participants.Id': <value> }
Here is more documentation https://docs.mongodb.com/manual/tutorial/query-array-of-documents/
Related
This is a simple question for you guys...I am wondering how can I acess a specific Id that is inside the "followers", after querying the User by its id. In other words i am searching for the user by its Id, and then I want to check the ids that are inside the followers.
For example: I have an Id saved in one variable "x", and I want to check if this Id "x" is inside of the followers array.
The model looks like this:
var UserSchema = new mongoose.Schema({
followers: [
{
type: mongoose.Schema.Types.ObjectId,
ref: 'User'
}
]
});
module.exports = mongoose.model("User", UserSchema);
And the code that I am using is this one:
User.findById(req.params.id,'followers', function(err,name){
if(err){
console.log(err)
} else{
console.log(name);
}
});
It looks like I can print the user id and the id's that are inside the "followers", but i am not managing to see if the desired Id is inside of "followers" array or not.Can anyone help me with it?
Thank you for your attention!
I think you need to create nested for loop because you have an array of users according to user schema and each user has an array of followers and to solve this, you need to create for loop for user schema and inside that loop you will loop through all followers inside that user and check whether the id that you have equals to their id.
Since followers is an array of IDs (document references), if the query is for a single follower match you can use a shorthand of {followers: SOME_ID} or if it is an array then you can use {followers: {$all: [SOME_ID, SOME_OTHER_ID]}}. See the Mongo documentation for more information.
Using an array to match for example would look like the following.
User.findOne({_id: req.params.id, followers: {$all: [SOME_ID, SOME_OTHER_ID]}}, function(err, name) {
if (err) {
console.log(err)
} else {
console.log(name);
}
});
I originally have these two schemas:
var UserSchema = new Schema({
first: String,
last: String
});
var SaleSchema = new Schema({
createdAt: Date,
registeredBy: { type: Schema.ObjectId, ref: 'User' }
});
But I want to edit my SaleSchema to save the user name instead of the ID, so I changed it for:
var SaleSchema = new Schema({
createdAt: Date,
registeredBy: String
});
Next, I wanted to edit all the Sales documents and replace the user IDs on registeredBy for the user's full name, but I can't seem to be able to perform a find query for the old ID's.
Long story short, this query returns no matches on mongoose, but it works perfectly using the mongo console:
Mongoose
Sale.find({ registeredBy: '57ea0cbb47431f0b43b87d42' })
.then(results => res.json(results))
.catch(err => res.status(500).json(err));
// result: []
MongoDB console
db.sales.find({ registeredBy: '57ea0cbb47431f0b43b87d42' })
// result: 8 elements
After I modify my schema's property back to ObjectId, the mongoose query works again. Since I need to migrate to a new datatype, I want to be able to query and store both types of values. Is this possible?
Good question this is a complicated edge case. I am not super familiar with Mongoose specifically, but one way to do this would be to migrate your data at a lower level. For example, create a mongo script that uses the low-level mongo API to do the migration, something along the lines of:
db.sales.find().forEach(function(doc){
var user = db.users.find({ _id: doc.registeredBy });
db.sales.update({ _id: doc._id, }, {
$set: { registeredBy: user.first + ' ' + user.last }
});
});
This is similar to what a module like https://github.com/balmasi/migrate-mongoose does, but I've personally found it easier to use mongo scripts on the cli directly.
mongo < sale-schema-migration.js
Using: node/express/mongodb/mongoose
With the setup listed above, I have created my schema and model and can query as needed. What I'm wondering how to do though is, pass the express request.query object to Model.find() in mongoose to match and query the _id of a nested document. In this instance, the query may look something like:
http://domain.com/api/object._id=57902aeec07ffa2290f179fe
Where object is a nested object that exists elsewhere in the database. I can easily query other fields. _id is the only one giving an issue. It returns an empty array of matches.
Can this be done?
This is an example and not the ACTUAL schema but this gets the point across..
let Category = mongoose.Schema({
name: String
})
let Product = mongoose.Schema({
name: String,
description:String,
category:Category
})
// sample category..
{
_id:ObjectId("1234567890"),
name: 'Sample Category'
}
// sample product
{
_id:ObjectId("0987654321"),
name:'Sample Product',
description:'Sample Product Description',
category: {
_id:ObjectId("1234567890"),
name: 'Sample Category'
}
}
So, what I'm looking for is... if I have the following in express..
app.get('/products',function(req,res,next){
let query = req.query
ProductModel.find(query).exec(function(err,docs){
res.json(docs)
})
})
This would allow me to specify anything I want in the query parameters as a query. So I could..
http://domain.com/api/products?name=String
http://domain.com/api/products?description=String
http://domain.com/api/products?category.name=String
I can query by category.name like this, but I can't do:
http://domain.com/api/products?category._id=1234567890
This returns an empty array
Change your query to http://domain.com/api/object/57902aeec07ffa2290f179fe and try
app.get('/api/object/:_id', function(req, res) {
// req._id is Mongo Document Id
// change MyModel to your model name
MyModel.findOne( {'_id' : req._id }, function(err, doc){
// do smth with this document
console.log(doc);
});
});
or try this one
http://domain.com/api/object?id=57902aeec07ffa2290f179fe
app.get('/api/object', function(req, res) {
var id = req.param('id');
MyModel.findOne( {'_id' : id }, function(err, doc){
console.log(doc);
});
})
First of all increase your skills in getting URL and POST Parameters by this article.
Read official Express 4.x API Documentation
Never mind I feel ridiculous. It works just as I posted above.. after I fixed an error in my schema.
I have the following (simplified) Schema
var options = {discriminatorKey:'kind'};
var activitySchema = new Schema(
{
title:{type:String}
},options
);
var Activity = mongoose.model('Activity', activitySchema);
var dateActivitySchema = new Schema({
postedBy:{type:Schema.Types.ObjectId,ref:'User',required:true}
},options);
var eventActivitySchema = new Schema({
details:{
eventType:{type:String, enum:['mixed','women','men']}
}
},options);
I have a function that returns a mix of both child documents - date activities and event activities. However when I try to populate the postedBy field it does not populate the data as expected.
Activity.aggregate([
{
$match:{
$or:[{
postedBy:{$in:results[0].userIDs}
},
{
'details.eventType':eventGenderInterestedInMapper(user.gender,user.preferences.interestedInGenders),
kind:'Event'
}]
}
}
],function(err,results){
Activity.populate(results,{path:'postedBy'},function(err,results){
if (err) return cb(err,null);
return cb(null,results);
});
});
Any way I can populate this child field from the base schema call or do I have to include the field in the base schema? I'm using the latest version of mongoose and from what I've found this functionality seems to be supported but it's not populating.
Edit: It populates only if the returned documents are ALL date activities. If there is one event activity then it populates none of the documents
Due to a management decision, we are using userId for the users collection, postId for the posts collection, and topicId for the topics collection, instead of '_id' for each collection as the unique identifier.
This causes a few problems getting started - one of the problems I have encountered is with upserts -
Using Mongoose, we have a schema that restricts userId to be a unique value - but when doing an update on a user model, with upsert set to true, MongoDB appears to only look at the ObjectIds of a collection to see if the same one exists - it doesn't check to see if a model already exists with the same userId - therefore Mongo does an insert instead of an update.
let me illustrate this with some data:
let's say the user's collection has one document:
{
_id:'561b0fad638e99481ab6d84a'
userId:3,
name:'foo'
}
we then run:
User.update({userId:3},{"$set":{name:'bar'},{upsert:true},function(err,resp){
if(err){
// "errMessage": "insertDocument :: caused by :: 11000 E11000 duplicate key error index: app42153482.users.$userId_1 dup key: { : 3 }",
}
});
one would think that MongoDB would find the existing document with userId:3 and udpate it, so there must be something I am doing wrong since it's giving me the duplicate key error?
Typically the default value ObjectId is more ideal for the _id. Here, in this situation you can either override the default _id or you can have your own field for id(like userId in your case).
Use a separate counters collection to track the last number sequence used. The _id field contains the sequence name and the seq field contains the last value of the sequence.
Insert into the counters collection, the initial value for the userid:
db.counters.insert( {
_id: "userid",
seq: 0 } )
Create a getNextSequence function that accepts a name of the sequence. The function uses the findAndModify() method to atomically increment the seq value and return this new value:
function getNextSequence(name) {
var ret = db.counters.findAndModify(
{
query: { _id: name },
update: { $inc: { seq: 1 } },
new: true
}
);
return ret.seq;
}
Use this getNextSequence() function during insert().
db.users.insert(
{
_id: getNextSequence("userid"),
name: "Sarah C."
}
)
db.users.insert(
{
_id: getNextSequence("userid"),
name: "Bob D."
}
)
This way you can maintain as many sequences as you want in the same counter collection. For the upsert issue, check out the Optimistic Loop block in this link Create an auto-increment sequence field.
The second approach is to use a mongoose middleware like mongodb-autoincrement.
Hope it helps.
I don't know which versions of MongoDB and Mongoose you are using, but I couldn't reproduce your problem with MongoDB 3.0 and Mongoose 4.1.10.
I made a sample for you which will create and save a new user, update (using upsert) it, and create another one through an upsert. Try running this code:
"use strict";
var mongoose=require("mongoose");
var Schema = require('mongoose').Schema;
var ObjectId = mongoose.Schema.Types.ObjectId;
// Connect to test
mongoose.connect("mongodb://localhost:27017/test");
// Lets create your schema
var userSchema = new Schema({
_id: ObjectId,
userId: {type: Number, unique: true },
name: String
});
var User = mongoose.model("User", userSchema, "Users");
User.remove() // Let's prune our collection to start clean
.then( function() {
// Create our sample record
var myUser = new User({
_id:'561b0fad638e99481ab6d84a',
userId:3,
name:'foo'
});
return myUser.save();
})
.then( function() {
// Now its time to update (upsert userId 3)
return User.update({userId:3},{"$set":{name:'bar'}},{upsert:true});
})
.then( function() {
// Now its time to insert (upsert userId 4)
return User.update({userId:4},{"$set":{name:'bee'}},{upsert:true});
})
.then( function() {
// Lets show what we have inserted
return User.find().then(function(data) {console.log(data)});
})
.catch( function(err) {
// Show errors if anything goes wrong
console.error("ERROR", err);
})
.then( function() {
mongoose.disconnect();
});
Following the documentation (of MongoDB 3.0) upsert:true will only not insert a non-existing document if your query conditions match on the _id field.
See: https://docs.mongodb.org/manual/reference/method/db.collection.update/#mongodb30-upsert-id
Why are you not using the user_name for a user as unique id?
Because auto-incrementing fields as ids are a bad practice to use in a mongodb environment, especially if you want to use sharding
=> all your inserts will occur on the latest shard
=> the mongodb cluster will have to rebalance often / redistribute the data around.
(Currently this will not occur on your system as you still use the generated _id field)
You can off course also create a unique index on the user_id field:
https://docs.mongodb.org/manual/core/index-unique/#index-type-unique