I have a data like below in MongoDB.
const A = { uid: '1234',
works: [
{ name: 'car',
item:['tire','wheel']
},
{ name: 'ship',
item:['tire','wheel']
}
]
My goal is to find whether the name duplicated exists or not.
In conclusion, I want to get only the names.
So 'res.send(result)' gives me like '[car, ship]'.
But the code below doesn't work. How can I make that function? Thank you so much.
const workName = await User.findOne({
uid: userID, works:{$in:['name']}
});
The easy way is to find the aggregate of name and check if the count is greater than one. Since it is inside the the array we need to unwind it.
The below query works, to detect if a sub document contain duplicates for each document.
db.getCollection('collection_name').aggregate([{"$unwind":"$works"} ,{"$group":{"_id":{"name":"$works.name","uid":"$uid"},"count":{"$sum":1}}},{"$match":{"count":{"$gte":2}}}])
if you want to find in all the documents remove uid from _id of group.
Related
I just started using Primsa 2 so I am still a noob at this but all I am trying to do is create a flat array of strings(Array<number>) based on the values I get from a specific field. Right now when I target that field it gives me an array of objects like this: userIds: [{ issueId: 1, userId: 1 }]
All I want is the value I get from the userId key and the array to return like this userIds: [ 1 ]. I was able to fix this with some formatting code after the query which was done like so:
const issues = project.issues.map(issue => ({ ...issue, userIds: [...issue.userIds.map((id) => id.userId)] }))
const _project = { ...project, issues }
However, this doesn't seem like the most optimal solution. If this is the only way that is fine but I assume with the power that Prisma has for querying, this is something I can do just in the query alone?
For reference, my query currently looks like this:
const project = await prisma.project.findFirst({
where: { id: req.currentUser.projectId },
include: { users: true, issues: { include: { userIds: true } } },
})
Thanks in advance!
Can you show your schema? Perhaps you can model the relation differently. However, unless if you provide a field, userIds, that is a flat array and not a field of a an other relation it will be returned as a list of objects as you have already.
How do you go about formatting the data response from mongoose? For a simple Post Schema
const postSchema = new mongoose.Schema({
title: {
type: String,
required: true,
}
},{
timestamps: true
});
Whenever I do a GET request to find all the post, It returns me all its fields including _id and __v in which I wouldn't want to return those fields in an API.
Is there a way I would select only certain fields that I would want to return?
As far as I've found was that I could set a second parameter of title onto my query and it would return only the _id and title.
const post = await Post.find({},'title');
I find the method above isn't the proper way to filter fields in cases in the future where the values are deeply nested object and we would like to pick out certain values.
Is there perhaps a way to create a Model/Class and pick the fields based on the Model/Class and return the respond?
You can use select from mongoose.
You can either select only the fields you want.
var find = await model.find({}).select("my_field")
Or not show the fields you don't want
var find = await model.find({}).select("-my_field")
Check the documentation
In our Mongoose model, we have a product referring to an article.
this is a piece of the schema:
const product = new Schema({
article_id: Schema.Types.ObjectId,
title: String,
description: String,
...
In the API we are looking for products that are referring to a list of specific articles, and I wanted to use the $in operator:
const articles = ["5dcd2a95d7e2999332441825",
"5dcd2a95d7e2999332441827",
"5dcd2a96d7e2999332441829"]
filter.article_id = {
$in: articles.map(
article => new mongoose.Types.ObjectId(article)
),
};
return Product.find({ ...filter })
This returns 0 records, whereas I know for sure it should have returned at least 3. Looking at the console log, all that has happened is that the double quotes have been removed from the array during the ObjectId conversion.
Then I tried a different approach by returning {$oid: "id goes here"} for each mapped array item:
const articles = ["5dcd2a95d7e2999332441825",
"5dcd2a95d7e2999332441827",
"5dcd2a96d7e2999332441829"]
filter.article_id = {
$in: articles.map(
article => ({$oid: article})
),
};
return Product.find({ ...filter })
This gives a different array:
console.log(filter);
// {article_id: {$in: [{$oid: "5dcd2a95d7e2999332441825"}, {$oid: "5dcd2a95d7e2999332441827"}, {$oid: "5dcd2a96d7e2999332441829"}]}}
But in this case I get following error:
CastError: Cast to ObjectId failed for value "\"{$oid: \"5dcd2a95d7e2999332441825\"}\"".
Though - if I take that particular console logged filter and pass it in Studio 3T as a filter, I do indeed get the desired results.
Any idea what I doing wrong in this case?
Frick me! I am just a big idiot.. Apparently there was a .skip(10) added after the find() method -.-'.... Now I understand why 0 records where returned... Been spending hours on this..
For future references, Mongoose casts strings to ObjectIds automatically if defined in Schema. Therefor following is working exactly as it should given you don't skip the first 10 records:
const articles = ["5dcd2a95d7e2999332441825",
"5dcd2a95d7e2999332441827",
"5dcd2a96d7e2999332441829"]
filter.article_id = {
$in: articles
};
return Product.find({ ...filter }) // Note that I DON'T put .skip() here..
I'm still in the middle of getting familiar with mongoDB queries so my problem might be very easy for you guys.
The problem is -
I have a document as shown in 'document.jpg'
document.jpg
Both of these documents are having one entry '5ac649444f3df45be852df84' under their products array. I want to remove this entry. I have the name of these two documents in an array and also have this entry '5ac649444f3df45be852df84' -
arr = ['andwived', 'QA Infotech']
productId = 5ac649444f3df45be852df84
Now the query I am using is -
enter code here
productId = mongoose.Types.ObjectId(productId)
Org.update(
{
'name':{"$in":[arr]}
},
{
$pull: {'products': productId}
},
callback
)
This is not giving any error but not removing the mentioned id either. Please help.
Try this..
const productId = mongoose.Types.ObjectId('5ac649444f3df45be852df84');
const arr = ['andwived', 'QA Infotech'];
Org.updateMany(
{
name: {$in: arr}
},
{
$pull: {products: productId}
},
callback
);
I am very new to meteor.js and try to build an application with it. This time I wanted to try it over MEAN stack but at this point I am struggled to understand how to join two collection on server side...
I want very identical behaviour like mongodb populate to fetch some properties of inner document.
Let me tell you about my collection it is something like this
{
name: 'Name',
lastName: 'LastName',
anotherObject: '_id of another object'
}
and another object has some fields
{
neededField1: 'asd',
neededField2: 'zxc',
notNeededField: 'qwe'
}
So whenever I made a REST call to retrieve the first object I want it contains only neededFields of inner object so I need join them at backend but I cannot find a proper way to do it.
So far while searching it I saw some packages here is the list
Meteor Collections Helper
Publish with Relations
Reactive joins in Meteor (article)
Joins in Meteor.js (article)
Meteor Publish Composite
You will find the reywood:publish-composite useful for "joining" related collections even though SQL-like joins are not really practical in Mongo and Meteor. What you'll end up with is the appropriate documents and fields from each collection.
Using myCollection and otherCollection as pseudonyms for your two collections:
Meteor.publishComposite('pseudoJoin', {
find: function() {
return myCollection.find();
},
children: [
{
find: function(doc) {
return otherCollection.find(
{ _id: post.anotherObject },
{ fields: { neededField1: 1, neededField2: 1 } });
}
}
]
});
Note that the _id field of the otherCollection will be included automatically even though it isn't in the list of fields.
Update based on comments
Since you're only looking to return data to a REST call you don't have to worry about cursors or reactivity.
var myArray = myCollection.find().fetch();
var myOtherObject = {};
var joinedArray = myArray.map(function(el){
myOtherObject = otherCollection.findOne({ _id: el.anotherObject });
return {
_id: el._id,
name: el.name,
lastName: el.lastName,
neededField1: myOtherObject.neededField1,
neededField2: myOtherObject.neededField2
}
});
console.log(joinedArray); // These should be the droids you're looking for
This is based on a 1:1 relation. If there are many related objects then you have to repeat the parent object to the number of children.