I am using Meteor/Mongo with Typescript/Javascript.
I have a chat app I am developing. I get a result set from Mongo.
const chats: Mongo.Cursor<Chat> = Chats.find(
{ memberIds: 'J65'},
{
sort: { lastMessageCreatedAt: -1 },
transform: this.transformChat.bind(this),
fields: { memberIds: 1, lastMessageCreatedAt: 1 }
}
);
This returns the Chats for J65 .
Question
Is it possible to have multiple memberIds? i.e. return the results for more than one matching id
More info
I have tried this with no success, i.e. it returns nothing even though there is a match (no errors though).
let registeredIds: String[] = ['J65', 'J66'];
...
{ memberIds: registeredIds },
this is what is in the database:
[
{
"_id": "CHb8FSuGSfZMPhkrW",
"memberIds": [
"P9",
"J64"
]
},
{
"_id": "uMSJjHheTp7RhGdH3",
"memberIds": [
"P9",
"J65"
]
},
{
"_id": "e6ZMmRaJLPptF63z8",
"memberIds": [
"P9",
"J66"
]
}
]
You should use the $in operator.
Your code shall look like:
const chats: Mongo.Cursor<Chat> = Chats.find(
{ memberIds: {$in:['J65','J66','J67']},
{
sort: { lastMessageCreatedAt: -1 },
transform: this.transformChat.bind(this),
fields: { memberIds: 1, lastMessageCreatedAt: 1 }
}
);
Refer docs for more information.
Related
Is it possible do same filtering as in js
const list = [
{
a: 1,
"mostImportant": "qwer",
"lessImportant": "rty"
},
{
a: 2,
"lessImportant": "weRt",
"notImportant": "asd",
},
{
a: 3,
"mostImportant": "qwe2",
"notImportant": "asd",
}
];
list.filter((data) => {
data.attrToSearch = data.mostImportant || data.lessImportant || data.notImportant;
return data.attrToSearch.match(/wer/i);
});
in MongoDB?
Loot at example:
https://mongoplayground.net/p/VQdfoQ-HQV4
So I want to attrToSearch contain value of first not blank attr with next order mostImportant, lessImportant, notImportant
and then match by regex.
Expected result is receive first two documents
Appreciate your help
Approach 1: With $ifNull
Updated
$ifNull only checks whether the value is null but does not cover checking for the empty string.
Hence, according to the attached JS function which skips for null, undefined, empty string value and takes the following value, you need to set the field value as null if it is found out with an empty string via $cond.
db.collection.aggregate([
{
$addFields: {
mostImportant: {
$cond: {
if: {
$eq: [
"$mostImportant",
""
]
},
then: null,
else: "$mostImportant"
}
},
lessImportant: {
$cond: {
if: {
$eq: [
"$lessImportant",
""
]
},
then: null,
else: "$lessImportant"
}
},
notImportant: {
$cond: {
if: {
$eq: [
"$notImportant",
""
]
},
then: null,
else: "$notImportant"
}
}
}
},
{
"$addFields": {
"attrToSearch": {
$ifNull: [
"$mostImportant",
"$lessImportant",
"$notImportant"
]
}
}
},
{
"$match": {
attrToSearch: {
$regex: "wer",
$options: "i"
}
}
}
])
Demo Approach 1 # Mongo Playground
Approach 2: With $function
Via $function, it allows you to write a user-defined function (UDF) with JavaScript support.
db.collection.aggregate([
{
"$addFields": {
"attrToSearch": {
$function: {
body: "function(mostImportant, lessImportant, notImportant) { return mostImportant || lessImportant || notImportant; }",
args: [
"$mostImportant",
"$lessImportant",
"$notImportant"
],
lang: "js"
}
}
}
},
{
"$match": {
attrToSearch: {
$regex: "wer",
$options: "i"
}
}
}
])
Demo Approach 2 # Mongo Playground
how to find array length from a specific mongoose model ?
{
"_id": {
"$oid": "626cf1ccb6da65761db4b146"
},
"ID_NUM": "ID=2796414693",
"SET_ARRAY": [
"sruMkdGUeRbWZz6FSz",
"6U7ugxem7Y0/ellBUF"
],
"__v": 0
}
I did
const lens = await model.findOne({ ID_NUM: "ID=2796414693" })
then
console.log(lens.SET_ARRAY.length)
I get no error and no result.
You can use $size of mongo aggregate:
const lens = await model.findOne(
[{
$match: {
ID_NUM: "ID=2796414693",
}
},
{
$project: {
_id: 0,
ARRAY_LEN: {
$size: "$SET_ARRAY"
}
}
}
]
)
I have two collections: Sharing and Material.
Sharing:
{
from_id: 2
to_id: 1
material_id: material1
}
Material:
{
_id: material1
organization_id: 2
},
{
_id: material2
organization_id: 1
},
{
_id: material3
organization_id: 1
},
--Edit:
There are three materials, 2 belong to organization_id(1) and 1 belongs to organization_id(2). The organization_id does not match 1 in material1 (and instead belongs to material2), but in the Sharing collection, the to_id does match 1. If the match exists, I'd like to find the Material document _id which is equal to the material_id of Sharing AND find the Material documents where the organization_id is equal to 1.
I'd like to check if a field in Sharing (to_id) has a value that is equal to a field in Material (organization_id) AND check if organization_id is equal to 1. If there is a document that exists from this, do another check to find whether the _id of Material is equal to the material_id of Sharing and return all documents & the total count.
If there is no equal value, I'd like to omit that result and send the object with only organization_id equal to 1 and get the total count of this result.
Right now, I do it in a very inefficient way using .map() to find this. Below is my code:
export const getMaterials = async (req, res) => {
const sharing = await Sharing.find({to_id: 1});
let doneLoad;
try {
if (sharing && sharing.length>0) {
const sharingTotal = await Material.find( {$or: [ {organization_id: 1}, {_id: sharing.map((item) => item.material_id)} ] } ).countDocuments();
const sharingMats = await Material.find( {$or: [ {organization_id: 1}, {_id: sharing.map((item) => item.material_id)} ] } );
res.status(200).json({data: sharingMats});
doneLoad= true;
}
else if (!doneLoad) {
const materialTotal = await Material.find({organization_id: 1}).countDocuments();
const materials = await Material.find({organization_id: 1});
res.status(200).json({data: materials});
}
} catch (error) {
res.status(404).json({ message: error.message });
}
}
I have tried using aggregation to get my desired result but I cannot find any solution that fits my requirements. Any help would be great as I am quite new to using mongodb. Thanks.
Edit (desired result):
Materials: [
{
_id: material1,
organization_id: 1
},
{
_id: material2,
organization_id: 1
},
{
_id: material3,
organization_id: 1
}
]
You can use sub-pipeline in a $lookup to perform the filtering. $addFields the count using $size later.
db.Sharing.aggregate([
{
"$match": {
to_id: 1
}
},
{
"$lookup": {
"from": "Material",
"let": {
to_id: "$to_id",
material_id: "$material_id"
},
"pipeline": [
{
"$match": {
$expr: {
$or: [
{
$eq: [
"$$to_id",
"$organization_id"
]
},
{
$eq: [
"$$material_id",
"$_id"
]
}
]
}
}
},
{
"$addFields": {
"organization_id": 1
}
}
],
"as": "materialLookup"
}
},
{
"$addFields": {
"materialCount": {
$size: "$materialLookup"
}
}
}
])
Here is the Mongo playground for your reference.
I have such a schema:
doc:
{
//Some fields
visits:
[
{
userID: Int32
time: Int64
}
]
}
I want to first check if a specific userID exists, if not, push a document with that userID and system time, else just update time value. I know neither $push nor $addToSet are not able to do that. Also using $ with upsert:true doesn't work, because of official documentation advice which says DB will use $ as field name instead of operator when trying to upsert.
Please guide me about this. Thanks
You can use $addToSet to add an item to the array and $set to update an existing item in this array.
The following will add a new item to the array if the userID is not found in the array :
db.doc.update({
visits: {
"$not": {
"$elemMatch": {
"userID": 4
}
}
}
}, {
$addToSet: {
visits: {
"userID": 4,
"time": 1482607614
}
}
}, { multi: true });
The following will update the subdocument array item if it matches the userId :
db.doc.update({ "visits.userID": 2 }, {
$set: {
"visits.$.time": 1482607614
}
}, { multi: true });
const p = await Transaction.findOneAndUpdate(
{
_id: data.id,
'products.id': { $nin: [product.id] },
},
{
$inc: {
actualCost: product.mrp,
},
$push: {
products: { id: product.id },
},
},
{ new: true }
);
or
db.collection.aggregate([
{
"$match": {
"_id": 1
}
},
{
"$match": {
"sizes.id": {
"$nin": [
7
]
}
}
},
{
"$set": {
"price": 20
}
}
])
https://mongoplayground.net/p/BguFa6E9Tra
I know it's very late. But it may help others. Starting from mongo4.4, we can use $function to use a custom function to implement our own logic. Also, we can use the bulk operation to achieve this output.
Assuming the existing data is as below
{
"_id" : ObjectId("62de4e31daa9b8acd56656ba"),
"entrance" : "Entrance1",
"visits" : [
{
"userId" : 1,
"time" : 1658736074
},
{
"userId" : 2,
"time" : 1658736671
}
]
}
Solution 1: using custom function
db.visitors.updateMany(
{_id: ObjectId('62de4e31daa9b8acd56656ba')},
[
{
$set: {
visits: {
$function: {
lang: "js",
args: ["$visits"],
body: function(visits) {
let v = []
let input = {userId: 3, time: Math.floor(Date.now() / 1000)};
if(Array.isArray(visits)) {
v = visits.filter(x => x.userId != input.userId)
}
v.push(input)
return v;
}
}
}
}
}
]
)
In NodeJS, the function body should be enclosed with ` character
...
lang: 'js',
args: ["$visits"],
body: `function(visits) {
let v = []
let input = {userId: 3, time: Math.floor(Date.now() / 1000)};
if(Array.isArray(visits)) {
v = visits.filter(x => x.userId != input.userId)
}
v.push(input)
return v;
}`
...
Solution 2: Using bulk operation:
Please note that the time here will be in the ISODate
var bulkOp = db.visitors.initializeOrderedBulkOp()
bulkOp.find({ _id: ObjectId('62de4e31daa9b8acd56656ba') }).updateOne({$pull: { visits: { userId: 2 }} });
bulkOp.find({ _id: ObjectId('62de4e31daa9b8acd56656ba') }).updateOne({$push: {visits: {userId: 2, time: new Date()}}})
bulkOp.execute()
Reference link
A great explanation of how to use new $position operator of Mongodb 2.6 by using Mongoose was given in the answer to my question. The suggested solution works perfect for simple arrays. If array is in subdocument or each element of array is array the suggested solution doesn't work. I mean something like this:
List.collection.update(
{/*....*/},
{ "$push": {
"subdocument.list": {
"$each": [ 1, 2, 3 ],
"$position": 0 }
}
},function(err,NumAffected) {
console.log("done");
});
List.collection.update(
{/*....*/},
{ "$push": {
"list1.$.list2": {
"$each": [ 1, 2, 3 ],
"$position": 0 }
}
},function(err,NumAffected) {
console.log("done");
});
In the current Mongoose version (4.4.2) you can use position like this:
Foo.update(query.id,
{
$push: {
arrayData: {
$each: [{
date: new Date
}], $position: 0
}
}
});
No sure what the issue is here:
db.list.insert({ "list": { "sub": [4] } })
db.list.update(
{},
{ "$push": { "list.sub": { "$each": [1,2,3], "$position": 0 } } }
)
{ "list" : { "sub" : [ 1, 2, 3, 4 ] } }
So that works as expected.
And for the other example:
db.list.insert({
outer: [
{
key: "a",
inner: [4]
},
{
key: "b",
inner: [4]
}
]
})
db.list.update(
{ "outer.key": "b" },
{ "$push": {
"outer.$.inner": {
"$each": [1,2,3], "$position": 0
}
}}
)
Again is as expected:
{
"outer" : [
{
"key" : "a",
"inner" : [
4
]
},
{
"key" : "b",
"inner" : [
1,
2,
3,
4
]
}
]
}
The interaction with specific drivers was already explained so there must be something different in the data, but if so then those statements are not valid.
And so exactly the same using Mongoose:
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
mongoose.connect('mongodb://localhost/nodetest');
var listSchema = new Schema({
});
var List = mongoose.model( "List", listSchema );
var Other = mongoose.model( "Other", listSchema );
List.collection.update(
{},
{ "$push": {
"list.sub": {
"$each": [ 1, 2, 3 ],
"$position": 0 }
}
},function(err,NumAffected) {
console.log("done");
}
);
Other.collection.update(
{ "outer.key": "b" },
{ "$push": {
"outer.$.inner": {
"$each": [ 1, 2, 3 ],
"$position": 0
}
}},function(err,NumAffected) {
console.log("done2")
}
);
I have found the code in the MongooseJS Model.update that omits support for the $position modifier.
In version 3.8.8, line 1928-1941 of query.js:
if ('$each' in val) {
obj[key] = {
$each: this._castUpdateVal(schema, val.$each, op)
}
if (val.$slice) {
obj[key].$slice = val.$slice | 0;
}
if (val.$sort) {
obj[key].$sort = val.$sort;
}
}
Here, obj[key] will be set to val.$each. You can see explicit support for setting the $slice & $sort modifiers, but the $position modifier will never be copied into obj[key].
So, although you may be able to by-pass the Model.update function of MongooseJS to directly access MongoDB's update function, it is clear that MongooseJS's Model.update function does not support the $position modifier.