// Item.js
schema: true,
attributes: {
testArray: {
type: 'array',
required: true,
array: true
}
}
I would like to find all items where the testArray attribute have a specific length.
I tried with this code below, but it doesn't work.
Item.find({testArray: {length: 2}}).exec(function (err, items) {
console.log(items);
});
I also tried with minLength, maxLength, size, but still no results.
Is there is a way to do that?
I'm using MongoDB via Sails.js/Waterline.
Actually this is in documentation
Model.where({ property: { '>': 100 }})
http://sailsjs.org/#!documentation/models
Another solution:
var query = { testArray: { $size: { $gt:2 } } };
Item.native(function(err, collection) {
collection.find(query).toArray(function(err, items) {
//items contains objects where testArray.length is greater than 2
});
});
You might run into problems depending on your mongodb version, then read http://www.mkyong.com/mongodb/mongodb-find-all-documents-where-an-array-list-size-is-greater-than-n/
Related
I have MongoDB database (with Mongoose) containing a collection of Products (among others), which looks like this:
[
{
name: 'Product A',
url: 'product-a',
category: 'accesory',
price: 12,
shortDescription: ['example description'],
technicalSpecs: [{ speed: 10, weight: 20 }],
images: [],
reviews: [],
relatedProducts: [
{
url: 'product-b',
name: 'Product B',
// to be added in Update query
//id: id_of_related_product
}
]
} /* other Product objects */
]
As every MongoDB document is provided with _id property by default, but within the relatedProducts array i only have url and name properties, i want to add the id property (associated with corresponding Product) for each object in the relatedProducts array, so i will be able to conveniently query and process those related products.
I came up with an idea to query all Products to get only those, which have non-empty relatedProducts array. Then i loop them and i search for Product model, which has specific url and name properties - this let's me get it's true (added by MongoDB) _id. At the end i want to add this _id to matching object inside relatedProducts array.
My code:
async function assignIDsToRelatedProducts(/* Model constructor */ Product) {
const productsWithRelatedOnes = await Product.find(
{ relatedProducts: { $ne: [] }}, ['relatedProducts', 'name', 'url']
);
for (const productItem of productsWithRelatedOnes) {
for (const relatedProduct of productItem.relatedProducts) {
const product = await Product.findOne(
{ url: relatedProduct.url, name: relatedProduct.name },
'_id'
);
// throws error
await productItem.updateOne(
{ 'relatedProducts.url': relatedProduct.url },
{ $set: { 'relatedProducts.$.id': product._id } }
);
}
}
}
However it throws the following error:
MongoError: Cannot create field 'url' in element {relatedProducts: [ /* array's objects here */ ]}
I don't know why MongoDB tries to create field 'url', as i use it to project/query url field (not create it) in updateOne method. How to fix this?
And - as i am newbie to MongoDB - is there a simpler way of achieving my goal? I feel that those two nested for..of loops are unnecessary, or even preceding creation of productsWithRelatedOnes variable is.
Is it possible to do with Mongoose Virtuals? I have tried it, but i couldn't match virtual property within the same Product Model - attach it to each object in relatedProducts array - after calling .execPopulate i received either an empty array or undefined (i am aware i should post at-the-time code of using Virtual, but for now i switched to above solution).
Although i didn't find solution or even reason of my problem, i solved it with a slightly other approach:
async function assignIDsToRelatedProducts(Product) {
const productsHavingRelatedProducts = Product.find({ relatedProducts: { $ne: [] }});
for await (const withRelated of productsHavingRelatedProducts) {
for (const relatedProductToUpdate of withRelated.relatedProducts) {
const relatedProduct = await Product
.findOne(
{ url: relatedProductToUpdate.url, name: relatedProductToUpdate.name },
['url', '_id']
);
await Product.updateMany(
{ 'relatedProducts.url': relatedProduct.url },
{ $set: { 'relatedProducts.$.id': relatedProduct._id } }
);
}
}
const amountOfAllProducts = await Product.find({}).countDocuments();
const amountOfRelatedProductsWithID = await Product
.find({ 'relatedProducts.id': { $exists: true } }).countDocuments();
console.log('All done?', amountOfAllProducts === amountOfRelatedProductsWithID);
}
Yet, i still suppose it can be done more concisely, without the initial looping. Hopefully somebody will suggest better solution. :)
I'm using mongoose to handle my DB queries. I'm trying to update a set of records entirely using this method. Mode code looks like this:
// prepare database query
const filter = { type: 'company' };
const update = req.body.payload; // payload contains the array of objects (i.e. updated records)
const options = { new: true, runValidators: true }
// find and update the taxonomy record
await Taxonomy.updateMany(filter, update, options);
But whenever I run this query I'm getting following error in the console:
Error [MongooseError]: Invalid update pipeline operator: "_id"
I suppose there is something wrong in my update payload. The req.body.payload looks like this:
[
{
_id: '5ef3d08c745428001d92f896',
type: 'company',
name: 'Company Size',
__v: 0
},
{
_id: '5ef3cdc5745428001d92f893',
type: 'company',
name: 'Company Industry',
__v: 0
}
]
Can you please tell me what actually is wrong here?
This is not the right usage of updateMany() - it is aimed to update many documents with a single change.
To update many documents use bulkwrite() (docs) :
async function myUpdateMany(Model, objectsArray) {
try {
let ops = []
for (let obj of (objectsArray || [])) {
ops.push({
updateOne: {
filter: { platformId: obj.platformId },
update: obj,
upsert: false, // set "true" if you want to add a new document if it doesn't exist
}
})
}
Model.bulkWrite(ops, { ordered: false });
} catch (err) {
throw Error("myUpdateMany error: " + err)
}
}
Regarding runValidators, according to this, it seems to work by default.
Assuming I have a collection in MongoDB with 5000 records, each containing something similar to:
{
"occupation":"Doctor",
"name": {
"first":"Jimmy",
"additional":"Smith"
}
Is there an easy way to rename the field "additional" to "last" in all documents? I saw the $rename operator in the documentation but I'm not really clear on how to specify a subfield.
You can use:
db.foo.update({}, {$rename:{"name.additional":"name.last"}}, false, true);
Or to just update the docs which contain the property:
db.foo.update({"name.additional": {$exists: true}}, {$rename:{"name.additional":"name.last"}}, false, true);
The false, true in the method above are: { upsert:false, multi:true }. You need the multi:true to update all your records.
Or you can use the former way:
remap = function (x) {
if (x.additional){
db.foo.update({_id:x._id}, {$set:{"name.last":x.name.additional}, $unset:{"name.additional":1}});
}
}
db.foo.find().forEach(remap);
In MongoDB 3.2 you can also use
db.students.updateMany( {}, { $rename: { "oldname": "newname" } } )
The general syntax of this is
db.collection.updateMany(filter, update, options)
https://docs.mongodb.com/manual/reference/method/db.collection.updateMany/
You can use the $rename field update operator:
db.collection.update(
{},
{ $rename: { 'name.additional': 'name.last' } },
{ multi: true }
)
If ever you need to do the same thing with mongoid:
Model.all.rename(:old_field, :new_field)
UPDATE
There is change in the syntax in monogoid 4.0.0:
Model.all.rename(old_field: :new_field)
Anyone could potentially use this command to rename a field from the collection (By not using any _id):
dbName.collectionName.update({}, {$rename:{"oldFieldName":"newFieldName"}}, false, true);
see FYI
I am using ,Mongo 3.4.0
The $rename operator updates the name of a field and has the following form:
{$rename: { <field1>: <newName1>, <field2>: <newName2>, ... } }
for e.g
db.getCollection('user').update( { _id: 1 }, { $rename: { 'fname': 'FirstName', 'lname': 'LastName' } } )
The new field name must differ from the existing field name. To specify a in an embedded document, use dot notation.
This operation renames the field nmae to name for all documents in the collection:
db.getCollection('user').updateMany( {}, { $rename: { "add": "Address" } } )
db.getCollection('user').update({}, {$rename:{"name.first":"name.FirstName"}}, false, true);
In the method above false, true are: { upsert:false, multi:true }.To update all your records, You need the multi:true.
Rename a Field in an Embedded Document
db.getCollection('user').update( { _id: 1 }, { $rename: { "name.first": "name.fname" } } )
use link : https://docs.mongodb.com/manual/reference/operator/update/rename/
This nodejs code just do that , as #Felix Yan mentioned former way seems to work just fine , i had some issues with other snipets hope this helps.
This will rename column "oldColumnName" to be "newColumnName" of table "documents"
var MongoClient = require('mongodb').MongoClient
, assert = require('assert');
// Connection URL
//var url = 'mongodb://localhost:27017/myproject';
var url = 'mongodb://myuser:mypwd#myserver.cloud.com:portNumber/databasename';
// Use connect method to connect to the server
MongoClient.connect(url, function(err, db) {
assert.equal(null, err);
console.log("Connected successfully to server");
renameDBColumn(db, function() {
db.close();
});
});
//
// This function should be used for renaming a field for all documents
//
var renameDBColumn = function(db, callback) {
// Get the documents collection
console.log("renaming database column of table documents");
//use the former way:
remap = function (x) {
if (x.oldColumnName){
db.collection('documents').update({_id:x._id}, {$set:{"newColumnName":x.oldColumnName}, $unset:{"oldColumnName":1}});
}
}
db.collection('documents').find().forEach(remap);
console.log("db table documents remap successfully!");
}
If you are using MongoMapper, this works:
Access.collection.update( {}, { '$rename' => { 'location' => 'location_info' } }, :multi => true )
I want to exclude some fields from result.
I have code:
users = db.select('users');
users.find( {}, { sort: { points:1 }, privateKey:0, publicKey:0}, function(err,data){
res.send(data);
});
I want to exclude private and public key from results.
Can I do that using monk?
You can also do it like this:
users.find( {}, { sort: { points:1 }, fields : { privateKey:0, publicKey:0} },
function(err,data){
res.send(data);
}
);
According to documentation first argument in find is filter and second is projection .But you have used sort . It will not able to interpret . You are trying to confuse projection with sort .Sorting should be after find and projection.
You can write projection like { field1: <boolean>, field2: <boolean> ... }
Note :
The find() method always includes the _id field even if the field is not explicitly stated to return in the projection parameter.
users.find({}, { privateKey: 0, publicKey: 0 }).sort({points: 1}).toArray(
function (err, data) {
res.send(data);
});
For me, I need to use the .project() method:
const someFunction = async () => {
const result = await users
.find({}, { sort: { points: 1 })
.project({ privateKey: 0, publicKey: 0});
};
This is what worked for me for excluding the _id field.
const courseChapters = await db
.collection("users")
.find({}, { projection: { _id: 0 } })
.toArray();
So the example in the question would look something like this.
users.find(
{},
{ projection: { points: 1, privateKey: 0, publicKey: 0 } },
function (err, data) {
res.send(data);
}
);
Check out this other answer that says you may need the fields field instead of projection depending upon your driver
I have a data set like this:
{
name : 'Doc Name',
photos: [
{
name: 'photo1',
url: 'http://.....'
},
{
name: 'photo2',
url: 'http://......'
}
],
etc ...
Using Monk https://github.com/LearnBoost/monk how do I update photo2? I can use an index as I am iterating over the fields at the moment.
My current attempt below gives me an error, and I can't use a variable for the JSON selector (as in the index).
collection.update({_id: data._id}, {photos[i].data: filename}, function(err, updatedata) {
});
Updating items at a position in an array can be done using the positional $ operator
collection.update(
{ _id: data.id, "photos.name": "photo2" },
{ $set: { "photos.$.data": "yourdata" } }
)
So I found a solution to my problem but there may be some better options and I will leave it unanswered. But for anyone else with the same issue this is what I did:
I extracted the MongoDB document as an object in Node.js, manipulated the document, and then replaced the entire array in a single update statement. For example here is some pseudo code:
collection.find({id: 1}, function(err, doc){
for(i=0; i< doc.array.length; i++) {
//do what you gotta do
doc.array[i].property = 'new value';
}
collection.update({id: 1}, {$set : {"doc.array": doc.array}}, function(err,doc){
console.log(err);
}
})