I have two arrays A and B of length n defined by the input,
fruit_ids = [{id: "id1"}, {id: "id2"}, {id:"id3"}];
fruit_names = [{name: "Orange"},{name: "Kiwi"},{name: "Banana"}]
and MongoDB documents
{ farm_id: "3344", fruits: [{name: "Orange", id:"id1"}, {name: "Kiwi", id:"id67"}]}
Now I want to write a Mongo query such that it pulls items from particular farm_id specified at array fruit_ids and fruit_names but at same index,
for example for the above input, I want for farm_id: 3344 {name: "Orange", id:"id1"} to get deleted.
Can anyone please help me.
You can use $pullAll operator to remove all the matching elements and build your update statement dynamically using below code:
var fruit_ids = [{id: "id1"}, {id: "id2"}, {id:"id3"}];
var fruit_names = [{name: "Orange"},{name: "Apple"},{name: "Banana"}];
var pullAll = {
$pullAll: { fruits: fruit_ids.map((id, index) => Object.assign(fruit_names[index], id)) }
}
db.col.update({ farm_id: 3344 }, pullAll)
This will only try to update the farm_id: 3344.
I was trying $pullAll as suggested by #mickl in his answer, but the thing is I had other fields inside my embedded documents and because $pullAll works only for exact matches, that's why I currently I am using $pull with $or on the array of embedded docs. I found this solution from this answer how-to-force-mongodb-pullall-to-disregard-document-order.
let arr = [{name: "Orange", id:"id1"}, {name: "Kiwi", id:"id67"}];
db.col.update(
{ farm_id: 3344 },
{ "$pull": { "fruits": { "$or": arr } }}
)
I have one array which has document ids.:
var ids = [ '5b3c7db4c079dc17dc75fc26', '5b3c7db4c079dc17dc75fc28' ]
I have one collection called Machines with documents inside.
I am trying to get documents from Machines collection using ids which are in my array.
Machines.find({ _id : { $in : ids } }).fetch();
this returns []
Try this:
var ids = [ ObjectId("5b3c7db4c079dc17dc75fc26"), ObjectId("5b3c7db4c079dc17dc75fc28") ]
Because Mongodb stores id as ObjectId("Actual Id")
Your
var ids = [ '5b3c7db4c079dc17dc75fc26', '5b3c7db4c079dc17dc75fc28' ]
looks like they're either hex string or native MongoDB BSON type ObjectID.
Try this for Meteor's Mongo:
import { Mongo } from 'meteor/mongo';
const ids = [
new Mongo.ObjectID('5b3c7db4c079dc17dc75fc26'),
new Mongo.ObjectID('5b3c7db4c079dc17dc75fc28'),
]
Machines.find({ _id : { $in : ids } }).fetch();
For better syntax, use .map() to get a new array of Mongo.ObjectID type IDs.
import { Mongo } from 'meteor/mongo';
const ids = ['5b3c7db4c079dc17dc75fc26', '5b3c7db4c079dc17dc75fc28', ...];
const mongoIds = ids.map(id => new Mongo.ObjectID(id));
Machines.find({ _id : { $in : mongoIds } }).fetch();
// if ids were ObjectIDs instead of literal strings
const objectIdToMongoIds = ids.map(id => new Mongo.ObjectID(id.toString()));
Machines.find({ _id: { $in: objectIdToMongoIds } });
meteor mongo es6 functional-programming
You can also try Machine.findById(req.params.id, () => {}
I have a one to many relationship between Dish and Review. One dish can have many reviews. Here is the Mongoose Schema for Dish and Review:
const mongoose = require('mongoose')
const Review = require('./reviewSchema')
// defining the structore of your document
let dishSchema = mongoose.Schema({
name : String,
price :Number,
imageURL :String,
reviews : [Review.schema]
})
// convert the schema into a model class which you can use in your code
const Dish = mongoose.model('Dish',dishSchema)
module.exports = Dish
const mongoose = require('mongoose')
let reviewSchema = mongoose.Schema({
title : String,
description :String
})
const Review = mongoose.model('Review',reviewSchema)
module.exports = Review
The problem I am having is that I want to fetch all the dishes if they have at least one review. Here is the code I wrote which returns an empty array.
Dish.find({
"reviews.length" : { $gt : 0 }
},function(error,dishes){
console.log(dishes)
})
What am I missing?
You can't explicitly refer to length property of an array. To check if array is not empty you can check if it's of $type "array" and if its $size is $not 0.
Dish.find({ reviews: { $type: "array", $not: { $size: 0 } } },
function(error,dishes){
console.log(dishes)
})
I have the following schema:
{
_id: objectID('593f8c591aa95154cfebe612'),
name: 'test'
businesses: [
{
_id: objectID('5967bd5f1aa9515fd9cdc87f'),
likes: [objectID('595796811aa9514c862033a1'), objectID('593f8c591ba95154cfebe790')]
}
{
_id: objectID('59579ff91aa9514f600cbba6'),
likes: [objectID('693f8c554aa95154cfebe146'), objectID('193f8c591ba95154cfeber790')]
}
]
}
I need to update "businesses.likes" where businesses._id equal to a center value and where businesses.likes contains certain objectID.
If the objectID exists in the array, I want to remove it.
This is what I have tried and didn't work correctly, because $in is searching in all the subdocuments, instead of the only subdocument where businesses._id = with my value:
db.col.update(
{ businesses._id: objectID('5967bd5f1aa9515fd9cdc87f'), 'businesses.likes': {$in: [objectID('193f8c591ba95154cfeber790')]}},
{$pull: {'businesses.$.likes': objectID('193f8c591ba95154cfeber790')}}
)
Any ideas how how I can write the query? Keep in mind that businesses.likes from different businesses can have the same objectID's.
Is there a way to update values in an object?
{
_id: 1,
name: 'John Smith',
items: [{
id: 1,
name: 'item 1',
value: 'one'
},{
id: 2,
name: 'item 2',
value: 'two'
}]
}
Lets say I want to update the name and value items for item where id = 2;
I have tried the following w/ mongoose:
var update = {name: 'updated item2', value: 'two updated'};
Person.update({'items.id': 2}, {'$set': {'items.$': update}}, function(err) { ...
Problem with this approach is that it updates/sets the entire object, therefore in this case I lose the id field.
Is there a better way in mongoose to set certain values in an array but leave other values alone?
I have also queried for just the Person:
Person.find({...}, function(err, person) {
person.items ..... // I might be able to search through all the items here and find item with id 2 then update the values I want and call person.save().
});
You're close; you should use dot notation in your use of the $ update operator to do that:
Person.update({'items.id': 2}, {'$set': {
'items.$.name': 'updated item2',
'items.$.value': 'two updated'
}}, function(err) { ...
model.update(
{ _id: 1, "items.id": "2" },
{
$set: {
"items.$.name": "yourValue",
"items.$.value": "yourvalue",
}
}
)
MongoDB Document
There is a mongoose way for doing it.
const itemId = 2;
const query = {
item._id: itemId
};
Person.findOne(query).then(doc => {
item = doc.items.id(itemId );
item["name"] = "new name";
item["value"] = "new value";
doc.save();
//sent respnse to client
}).catch(err => {
console.log('Oh! Dark')
});
There is one thing to remember, when you are searching the object in array on the basis of more than one condition then use $elemMatch
Person.update(
{
_id: 5,
grades: { $elemMatch: { grade: { $lte: 90 }, mean: { $gt: 80 } } }
},
{ $set: { "grades.$.std" : 6 } }
)
here is the docs
For each document, the update operator $set can set multiple values, so rather than replacing the entire object in the items array, you can set the name and value fields of the object individually.
{'$set': {'items.$.name': update.name , 'items.$.value': update.value}}
Below is an example of how to update the value in the array of objects more dynamically.
Person.findOneAndUpdate({_id: id},
{
"$set": {[`items.$[outer].${propertyName}`]: value}
},
{
"arrayFilters": [{ "outer.id": itemId }]
},
function(err, response) {
...
})
Note that by doing it that way, you would be able to update even deeper levels of the nested array by adding additional arrayFilters and positional operator like so:
"$set": {[`items.$[outer].innerItems.$[inner].${propertyName}`]: value}
"arrayFilters":[{ "outer.id": itemId },{ "inner.id": innerItemId }]
More usage can be found in the official docs.
cleaner solution using findOneAndUpdate
await Person.findOneAndUpdate(
{ _id: id, 'items.id': 2 },
{
$set: {
'items.$.name': 'updated item2',
'items.$.value': 'two updated',
}
},
);
In Mongoose, we can update array value using $set inside dot(.) notation to specific value in following way
db.collection.update({"_id": args._id, "viewData._id": widgetId}, {$set: {"viewData.$.widgetData": widgetDoc.widgetData}})
Having tried other solutions which worked fine, but the pitfall of their answers is that only fields already existing would update adding upsert to it would do nothing, so I came up with this.
Person.update({'items.id': 2}, {$set: {
'items': { "item1", "item2", "item3", "item4" } }, {upsert:
true })
I had similar issues. Here is the cleanest way to do it.
const personQuery = {
_id: 1
}
const itemID = 2;
Person.findOne(personQuery).then(item => {
const audioIndex = item.items.map(item => item.id).indexOf(itemID);
item.items[audioIndex].name = 'Name value';
item.save();
});
Found this solution using dot-object and it helped me.
import dot from "dot-object";
const user = await User.findByIdAndUpdate(id, { ...dot.dot(req.body) });
I needed to update an array element with dynamic key-value pairs.
By mapping the update object to new keys containing the $ update operator, I am no longer bound to know the updated keys of the array element and instead assemble a new update object on the fly.
update = {
name: "Andy",
newKey: "new value"
}
new_update = Object.fromEntries(
Object.entries(update).map(
([k, v], i) => ["my_array.$." + k, v]
)
)
console.log({
"$set": new_update
})
In mongoose we can update, like simple array
user.updateInfoByIndex(0,"test")
User.methods.updateInfoByIndex = function(index, info) ={
this.arrayField[index]=info
this.save()
}
update(
{_id: 1, 'items.id': 2},
{'$set': {'items.$[]': update}},
{new: true})
Here is the doc about $[]: https://docs.mongodb.com/manual/reference/operator/update/positional-all/#up.S[]