So I'm working on a comments, I'm inserting them into collection of existing posts and I want to have more than one comment in my Mongo document.
This is how I set one property in a single document:
let result = await db.collection('posts').update({
_id : mongo.ObjectId(id)},
{$set : {comment : req.body.newComment }})
So how to insert more of them in a particular document?
You can use push operator to do that.
let result = await db.collection('posts').update(
{ _id: mongo.ObjectId(id) },
{ $push: {comment: req.body.newComment} })
MongoDB Official Documentation for push operator
Related
I'd like to configure an upsert. If _id already exists on my object, it recognizes that and updates the match. If _id doesn't exist, it should insert the new document and generate an _id. I'd expect { _id: obj._id } to work, but that overrides the auto-generation of _id. The document appears with _id: null. Is there a filter that would work for this? Do I need to route to insert/update in-code?
Edit: add query.
collection.updateOne(
{ _id: entity._id },
{ $set: entity },
{ upsert: true }
)
Edit: try delete.
Even when I delete the property, no luck.
const upsertTest = (collection) => {
const entity = { date: new Date() };
console.log(entity);
// { date: 2019-11-19T22:16:00.914Z }
const _id = entity._id;
delete entity._id;
console.log(entity);
// { date: 2019-11-19T22:16:00.914Z }
collection.updateOne(
{ _id: _id },
{ $set: entity },
{ upsert: true }
);
console.log(entity);
// { date: 2019-11-19T22:16:00.914Z }
}
But the new document is this:
screenshot of new document
You have to use $setOnInsert to Insert _id
let ObjectID = require('mongodb').ObjectID;
collection.updateOne(
{ _id: entity._id },
{ $set: entity,$setOnInsert:{_id:new ObjectID()}},
{ upsert: true }
)
As the name suggests it will set the _id on insert
If you are using mongodb then new ObjectID() should work,
If its mongoose then you can use mongoose.Types.ObjectId() to generate new ObjectID
Well I Found your Issue
Changed in version 3.0: When you execute an update() with upsert: true and the query matches no existing document, MongoDB will refuse to insert a new document if the query specifies conditions on the _id field.
So in a nutshell you cannot insert a new doc using upsert:true if your query is using _id, Reference
First of all, the _id property WILL always exist, whether you set it yourself or let it auto-generate. So there's no need to check if it exists.
The syntax for upsert is as follows:
db.collection.update({
_id: 'the id you want to check for' // can put any valid 'find' query here
}, {
$set: {
foo: 'bar',
biz: 'baz'
}
}, {
upsert: true
});
If a document with the given _id exists, it will be updated with the $set object. If it does not exist, a new one will be created with the properties of the $set object. If _id is not specified in the $set object, a new _id value will be auto-generated, or will keep using the existing _id value.
The key here is using $set, rather than putting the object right in there. Using set will merge and replace the properties. Without $set it will replace the entire document, removing any unset properties.
Edit: Now seeing the actual query you made, I would suggest you delete the _id property from the entity before setting it. This will make sure it is left alone.
const _id = entity._id;
delete entity._id;
// now do your query using the new `_id` value for the ID.
From our comments you mentioned you were using the local database. The local database allows _id to be null. Using any other DB should fix your issue.
If the entity._id is null then it will create a doc with _id null, We can solve this issue by adding Types.ObjectId(). If the _id doesn't exist then it will create a new document with the proper _id. otherwise, it will update the existing document.
const { Types } = require("mongoose")
collection.updateOne({ _id: Types.ObjectId(entity._id) },{ $set: entity },{ upsert: true})
I want update an _id field of one document. I know it's not really good practice. But for some technical reason, I need to update it.
If I try to update it I get:
db.clients.update({ _id: ObjectId("123")}, { $set: { _id: ObjectId("456")}})
Performing an update on the path '_id' would modify the immutable field '_id'
And the update is rejected. How I can update it?
You cannot update it. You'll have to save the document using a new _id, and then remove the old document.
// store the document in a variable
doc = db.clients.findOne({_id: ObjectId("4cc45467c55f4d2d2a000002")})
// set a new _id on the document
doc._id = ObjectId("4c8a331bda76c559ef000004")
// insert the document, using the new _id
db.clients.insert(doc)
// remove the document with the old _id
db.clients.remove({_id: ObjectId("4cc45467c55f4d2d2a000002")})
To do it for your whole collection you can also use a loop (based on Niels example):
db.status.find().forEach(function(doc){
doc._id=doc.UserId; db.status_new.insert(doc);
});
db.status_new.renameCollection("status", true);
In this case UserId was the new ID I wanted to use
In case, you want to rename _id in same collection (for instance, if you want to prefix some _ids):
db.someCollection.find().snapshot().forEach(function(doc) {
if (doc._id.indexOf("2019:") != 0) {
print("Processing: " + doc._id);
var oldDocId = doc._id;
doc._id = "2019:" + doc._id;
db.someCollection.insert(doc);
db.someCollection.remove({_id: oldDocId});
}
});
if (doc._id.indexOf("2019:") != 0) {... needed to prevent infinite loop, since forEach picks the inserted docs, even throught .snapshot() method used.
Here I have a solution that avoid multiple requests, for loops and old document removal.
You can easily create a new idea manually using something like:_id:ObjectId()
But knowing Mongo will automatically assign an _id if missing, you can use aggregate to create a $project containing all the fields of your document, but omit the field _id. You can then save it with $out
So if your document is:
{
"_id":ObjectId("5b5ed345cfbce6787588e480"),
"title": "foo",
"description": "bar"
}
Then your query will be:
db.getCollection('myCollection').aggregate([
{$match:
{_id: ObjectId("5b5ed345cfbce6787588e480")}
}
{$project:
{
title: '$title',
description: '$description'
}
},
{$out: 'myCollection'}
])
You can also create a new document from MongoDB compass or using command and set the specific _id value that you want.
As a very small improvement to the above answers i would suggest using
let doc1 = {... doc};
then
db.dyn_user_metricFormulaDefinitions.deleteOne({_id: doc._id});
This way we don't need to create extra variable to hold old _id.
Slightly modified example of #Florent Arlandis above where we insert _id from a different field in a document:
> db.coll.insertOne({ "_id": 1, "item": { "product": { "id": 11 } }, "source": "Good Store" })
{ "acknowledged" : true, "insertedId" : 1 }
> db.coll.aggregate( [ { $set: { _id : "$item.product.id" }}, { $out: "coll" } ]) // inserting _id you want for the current collection
> db.coll.find() // check that _id is changed
{ "_id" : 11, "item" : { "product" : { "id" : 11 } }, "source" : "Good Store" }
Do not use $match filter + $out as in #Florent Arlandis's answer since $out fully remove data in collection before inserting aggregate result, so effectively you will loose all data that don't match to $match filter
I'm new in MongoDB.I have read almost all relative posts but cannot find a proper answer for my case. Suppose you have the document:
{ "_id" : "5ad1..",
"linkedin" : { "linkedinId" : "NB..J", "username" : "dolguldur",
"followers":[{name:"John",email:"john#example.com},{name:"Elsa",email:"elsa#example.com}]
}
}
If a follower changes his email, how can i update his record with the new one;
Use the $elemMatch operator to select your desired nested object :
db.collection.update({
followers: {
$elemMatch: {
name: _follower_name,
email: _follower_email
}
}
}, {
"followers.$.email": new_mail
});
The $ positional operator will select the first nested object that match the filter in $elemMatch and update it.
I want update an _id field of one document. I know it's not really good practice. But for some technical reason, I need to update it.
If I try to update it I get:
db.clients.update({ _id: ObjectId("123")}, { $set: { _id: ObjectId("456")}})
Performing an update on the path '_id' would modify the immutable field '_id'
And the update is rejected. How I can update it?
You cannot update it. You'll have to save the document using a new _id, and then remove the old document.
// store the document in a variable
doc = db.clients.findOne({_id: ObjectId("4cc45467c55f4d2d2a000002")})
// set a new _id on the document
doc._id = ObjectId("4c8a331bda76c559ef000004")
// insert the document, using the new _id
db.clients.insert(doc)
// remove the document with the old _id
db.clients.remove({_id: ObjectId("4cc45467c55f4d2d2a000002")})
To do it for your whole collection you can also use a loop (based on Niels example):
db.status.find().forEach(function(doc){
doc._id=doc.UserId; db.status_new.insert(doc);
});
db.status_new.renameCollection("status", true);
In this case UserId was the new ID I wanted to use
In case, you want to rename _id in same collection (for instance, if you want to prefix some _ids):
db.someCollection.find().snapshot().forEach(function(doc) {
if (doc._id.indexOf("2019:") != 0) {
print("Processing: " + doc._id);
var oldDocId = doc._id;
doc._id = "2019:" + doc._id;
db.someCollection.insert(doc);
db.someCollection.remove({_id: oldDocId});
}
});
if (doc._id.indexOf("2019:") != 0) {... needed to prevent infinite loop, since forEach picks the inserted docs, even throught .snapshot() method used.
Here I have a solution that avoid multiple requests, for loops and old document removal.
You can easily create a new idea manually using something like:_id:ObjectId()
But knowing Mongo will automatically assign an _id if missing, you can use aggregate to create a $project containing all the fields of your document, but omit the field _id. You can then save it with $out
So if your document is:
{
"_id":ObjectId("5b5ed345cfbce6787588e480"),
"title": "foo",
"description": "bar"
}
Then your query will be:
db.getCollection('myCollection').aggregate([
{$match:
{_id: ObjectId("5b5ed345cfbce6787588e480")}
}
{$project:
{
title: '$title',
description: '$description'
}
},
{$out: 'myCollection'}
])
You can also create a new document from MongoDB compass or using command and set the specific _id value that you want.
As a very small improvement to the above answers i would suggest using
let doc1 = {... doc};
then
db.dyn_user_metricFormulaDefinitions.deleteOne({_id: doc._id});
This way we don't need to create extra variable to hold old _id.
Slightly modified example of #Florent Arlandis above where we insert _id from a different field in a document:
> db.coll.insertOne({ "_id": 1, "item": { "product": { "id": 11 } }, "source": "Good Store" })
{ "acknowledged" : true, "insertedId" : 1 }
> db.coll.aggregate( [ { $set: { _id : "$item.product.id" }}, { $out: "coll" } ]) // inserting _id you want for the current collection
> db.coll.find() // check that _id is changed
{ "_id" : 11, "item" : { "product" : { "id" : 11 } }, "source" : "Good Store" }
Do not use $match filter + $out as in #Florent Arlandis's answer since $out fully remove data in collection before inserting aggregate result, so effectively you will loose all data that don't match to $match filter
I want update an _id field of one document. I know it's not really good practice. But for some technical reason, I need to update it.
If I try to update it I get:
db.clients.update({ _id: ObjectId("123")}, { $set: { _id: ObjectId("456")}})
Performing an update on the path '_id' would modify the immutable field '_id'
And the update is rejected. How I can update it?
You cannot update it. You'll have to save the document using a new _id, and then remove the old document.
// store the document in a variable
doc = db.clients.findOne({_id: ObjectId("4cc45467c55f4d2d2a000002")})
// set a new _id on the document
doc._id = ObjectId("4c8a331bda76c559ef000004")
// insert the document, using the new _id
db.clients.insert(doc)
// remove the document with the old _id
db.clients.remove({_id: ObjectId("4cc45467c55f4d2d2a000002")})
To do it for your whole collection you can also use a loop (based on Niels example):
db.status.find().forEach(function(doc){
doc._id=doc.UserId; db.status_new.insert(doc);
});
db.status_new.renameCollection("status", true);
In this case UserId was the new ID I wanted to use
In case, you want to rename _id in same collection (for instance, if you want to prefix some _ids):
db.someCollection.find().snapshot().forEach(function(doc) {
if (doc._id.indexOf("2019:") != 0) {
print("Processing: " + doc._id);
var oldDocId = doc._id;
doc._id = "2019:" + doc._id;
db.someCollection.insert(doc);
db.someCollection.remove({_id: oldDocId});
}
});
if (doc._id.indexOf("2019:") != 0) {... needed to prevent infinite loop, since forEach picks the inserted docs, even throught .snapshot() method used.
Here I have a solution that avoid multiple requests, for loops and old document removal.
You can easily create a new idea manually using something like:_id:ObjectId()
But knowing Mongo will automatically assign an _id if missing, you can use aggregate to create a $project containing all the fields of your document, but omit the field _id. You can then save it with $out
So if your document is:
{
"_id":ObjectId("5b5ed345cfbce6787588e480"),
"title": "foo",
"description": "bar"
}
Then your query will be:
db.getCollection('myCollection').aggregate([
{$match:
{_id: ObjectId("5b5ed345cfbce6787588e480")}
}
{$project:
{
title: '$title',
description: '$description'
}
},
{$out: 'myCollection'}
])
You can also create a new document from MongoDB compass or using command and set the specific _id value that you want.
As a very small improvement to the above answers i would suggest using
let doc1 = {... doc};
then
db.dyn_user_metricFormulaDefinitions.deleteOne({_id: doc._id});
This way we don't need to create extra variable to hold old _id.
Slightly modified example of #Florent Arlandis above where we insert _id from a different field in a document:
> db.coll.insertOne({ "_id": 1, "item": { "product": { "id": 11 } }, "source": "Good Store" })
{ "acknowledged" : true, "insertedId" : 1 }
> db.coll.aggregate( [ { $set: { _id : "$item.product.id" }}, { $out: "coll" } ]) // inserting _id you want for the current collection
> db.coll.find() // check that _id is changed
{ "_id" : 11, "item" : { "product" : { "id" : 11 } }, "source" : "Good Store" }
Do not use $match filter + $out as in #Florent Arlandis's answer since $out fully remove data in collection before inserting aggregate result, so effectively you will loose all data that don't match to $match filter