I have a situation where a model changed at some point in time and I am faced with (for argument sake) half my data liks like this
{
_id: OID,
things: [{
_id:OID,
arm: string,
body: string
}],
other: string
}
and the other half of my data look like this
{
_id: OID,
things: [{
_id:OID,
upper_appendage: string,
body: string
}],
other: string
}
I would like to 'correct' half of the data - so that I DON'T have to accommodate both names for 'arm' in my application code.
I have tried a couple different things:
The first errors
db.getCollection('x')
.find({things:{$exists:true}})
.forEach(function (record) {
record.things.arm = record.things.upper_appendage;
db.users.save(record);
});
and this - which destroys all the other data in
db.getCollection('x')
.find({things:{$exists:true}})
.forEach(function (record) {
record.things = {
upper_appendage.arm = record.things.upper_appendage
};
db.users.save(record);
});
Keeping in mind that there is other data I want to maintain...
How can I do this???
the $rename operator should have worked for this job but unfortunately it doesn't seem to support nested array fields (as of mongodb server 4.2). instead you'd need a forEach like the following:
db.items.find({
things: {
$elemMatch: {
arm: {
$exists: true
}
}
}
}).forEach(function(item) {
for (i = 0; i != item.things.length; ++i)
{
item.things[i].upper_appendage = item.things[i].arm;
delete item.things[i].arm; ;
}
db.items.update({
_id: item._id
}, item);
})
note: i've assumed you want to make all records have upper_appendageand get rid of 'arm' field. if it's the other way you want, just switch things around.
Related
In my Movie schema, I have a field "release_date" who can contain nested subdocuments.
These subdocuments contains three fields :
country_code
date
details
I need to guarantee the first two fields are unique (primary key).
I first tried to set a unique index. But I finally realized that MongoDB does not support unique indexes on subdocuments.
Index is created, but validation does not trigger, and I can still add duplicates.
Then, I tried to modify my update function to prevent duplicates, as explained in this article (see Workarounds) : http://joegornick.com/2012/10/25/mongodb-unique-indexes-on-single-embedded-documents/
$ne works well but in my case, I have a combination of two fields, and it's a way more complicated...
$addToSet is nice, but not exactly what I am searching for, because "details" field can be not unique.
I also tried plugin like mongoose-unique-validator, but it does not work with subdocuments ...
I finally ended up with two queries. One for searching existing subdocument, another to add a subdocument if the previous query returns no document.
insertReleaseDate: async(root, args) => {
const { movieId, fields } = args
// Searching for an existing primary key
const document = await Movie.find(
{
_id: movieId,
release_date: {
$elemMatch: {
country_code: fields.country_code,
date: fields.date
}
}
}
)
if (document.length > 0) {
throw new Error('Duplicate error')
}
// Updating the document
const response = await Movie.updateOne(
{ _id: movieId },
{ $push: { release_date: fields } }
)
return response
}
This code works fine, but I would have preferred to use only one query.
Any idea ? I don't understand why it's so complicated as it should be a common usage.
Thanks RichieK for your answer ! It's working great.
Just take care to put the field name before "$not" like this :
insertReleaseDate: async(root, args) => {
const { movieId, fields } = args
const response = await Movie.updateOne(
{
_id: movieId,
release_date: {
$not: {
$elemMatch: {
country_code: fields.country_code,
date: fields.date
}
}
}
},
{ $push: { release_date: fields } }
)
return formatResponse(response, movieId)
}
Thanks a lot !
So I have found quite few related posts on SO on how to update a field in a sub array, such as this one here
What I want to achieve is basically the same thing, but updating a field in a subarray dynamically, instead of just calling the field name in the query.
Now I also found how to do that straight in the main object, but cant seem to do it in the sub array.
Code to insert dynamically in sub-object:
_.each(data.data, function(val, key) {
var obj = {};
obj['general.'+key] = val;
insert = 0 || (Documents.update(
{ _id: data._id },
{ $set: obj}
));
});
Here is the tree of what I am trying to do:
Documents: {
_id: '123123'
...
smallRoom:
[
_id: '456456'
name: 'name1'
description: 'description1'
],
[
...
]
}
Here is my code:
// insert a new object in smallRoom, with only the _id so far
var newID = new Mongo.ObjectID;
var createId = {_id: newID._str};
Documents.update({_id: data._id},{$push:{smallRooms: createId}})
And the part to insert the other fields:
_.each(data.data, function(val, key) {
var obj = {};
obj['simpleRoom.$'+key] = val;
console.log(Documents.update(
{
_id: data._id, <<== the document id that I want to update
smallRoom: {
$elemMatch:{
_id : newID._str, <<== the smallRoom id that I want to update
}
}
},
{
$set: obj
}
));
});
Ok, having said that, I understand I can insert the whole object straight away, not having to push every single field.
But I guess this question is more like, how does it work if smallRoom had 50 fields, and I want to update 3 random fields ? (So I would NEED to use the _each loop as I wouldnt know in advance which field to update, and would not want to replace the whole object)
I'm not sure I 100% understand your question, but I think the answer to what you are asking is to use the $ symbol.
Example:
Documents.update(
{
_id: data._id, smallRoom._id: newID._str
},
{
$set: { smallroom.$.name: 'new name' }
}
);
You are finding the document that matches the _id: data._id, then finding the object in the array smallRoom that has an _id equal to newId._str. Then you are using the $ sign to tell Mongo to update that object's name key.
Hope that helps
I'm trying to update a sub document on an existing collection. I'm getting a MongoDB error message.
"MongoError: The positional operator did not find the match needed from the query. Unexpanded update: articleWords.$ [409]"
From my Articles Simple Schema
"articleWords.$": {
type: Object
},
"articleWords.$.wordId": {
type: String,
label: 'Word ID'
},
"articleWords.$.word": {
type: String,
label: 'Word'
},
Update Function
function updateArticle(_id,wordArr) {
_.each(wordArr,function(elem) {
var ret = Articles.update(
{'_id': _id},
{ $set: { 'articleWords.$': { 'wordId': elem.wordId, 'word': elem.word } }
});
});
return true;
}
As you can see I am passing an array of objects. Is there a better way to do this than _.each ?
CLARIFICATION
Thank you to #corvid for the answer. I think I didn't make my question clear enough. There does exist an article record, but there is no data added to the articleWords attribute. Essentially we are updating a record but insert into the articleWords array.
A second attempt, is also not working
_.each(wordArr,function(elem) {
var ret = Articles.update(
{'_id': _id},
{ $set: { 'articleWords.$.wordId': elem.wordId, 'articleWords.$.word': elem.word } }
);
});
Yes, you need your selector to match something within the subdocument. For example,
Articles.update({
'_id': <someid>,
'words.wordId': <somewordid>
}, {
$set: {
'words.$.word': elem.word,
'words.$.wordId': elem.wordId
}
});
If the array doesn't exist yet then you're going about this in the hardest way possible. You can just set the entire array at one go:
var ret = Articles.update(
{'_id': _id},
{ $set: { articleWords: wordArr }}
);
I can see that wordArr already has the id and string. This will work as long as it doesn't have more content. If it does then you can just make a second version with the parts you want to keep.
Within a collection I am storing some data, mapped against a mobile device UID which is generated elsewhere. For example:
{
devices: {
'b2e4fe52d4ab57fd55fa': { model: 'aPhone', number: 1111111 },
'b2e4fe52d4ab57fd55fb': { model: 'bPhone', number: 2222222 },
'b2e4fe52d4ab57fd55fc': { model: 'cPhone', number: 3333333 }
}
}
Is there a way to retrieve the object representing one device without using the UID?
This would be easy for an array simply using an $elemMatch on either the model or number, but it seems it's use is limited only Arrays, is there an analogue operator for Documents?
is there an analogue operator for Documents
No. There is no operator to match and project a single key value pair inside a document, without knowing the key.
You will have to write the code to do the post processing on each devices document, which may look like:
var devices = db.devices.findOne().devices;
var keys = Object.keys(devices);
for(var i=0;i<keys.length;i++){
var device = devices[keys[i]];
if(device.model == 'aPhone' && device.number == 1111111)
{
print(keys[i]);
// do the processing here
break;
}
}
In case you had an option to change your schema as below, which is much more flexible and looks logically correct too,
db.devices.insert({
devices: [
{"id":"b2e4fe52d4ab57fd55fa", model: 'aPhone', number: 1111111 },
{"id":"b2e4fe52d4ab57fd55fb", model: 'bPhone', number: 2222222 },
{"id":"b2e4fe52d4ab57fd55fc", model: 'cPhone', number: 3333333 }
]
})
Then you have the luxury of achieving it with a simple find and project query.
db.devices.findOne({"devices.model":"aPhone",
"devices.number":1111111},
{"devices.$":1})
Use $where though not recommended if you have large data due to performance.
db.collection.find(
{ $where: function() {
var input = { model: 'aPhone', number: 1111111 };
if(this.devices != undefined){
for(var key in this.devices){
d = this.devices[key];
if (d.model==input.model && d.number==input.number) return true;
}
}
return false;
}})
I have a Collection that has documents with an array of nested objects.
Here is fixture code to populate the database:
if (Parents.find().count() == 0) {
var parentId = Parents.insert({
name: "Parent One"
});
Children.insert({
parent: parentId,
fields: [
{
_id: new Meteor.Collection.ObjectID(),
position: 3,
name: "three"
},
{
_id: new Meteor.Collection.ObjectID(),
position: 1,
name: "one"
},
{
_id: new Meteor.Collection.ObjectID(),
position: 2,
name: "two"
},
]
});
}
You might be asking yourself, why do I even need an ObjectID when I can just update based off of the names. This is a simplified example to a much more complex schema that I'm currently working on and the the nested object are going to be created dynamically, the ObjectID's are definitely going to be necessary to make this work.
Basically, I need a way to save those nested objects with a unique ID and be able to update the fields by their _id.
Here is my Method, and the call I'm making from the browser console:
Meteor.methods({
upChild: function( options ) {
console.log(new Meteor.Collection.ObjectID());
Children.update({_id: options._id, "fields._id": options.fieldId }, {$set: {"fields.$.position": options.position}}, function(error){
if(error) {
console.log(error);
} else {
console.log("success");
}
});
}
});
My call from the console:
Meteor.call('upChild', {
_id: "5NuiSNQdNcZwau92M",
fieldId: "9b93aa1ef3868d762b84d2f2",
position: 1
});
And here is a screenshot of the html where I'm rendering all of the data for the Parents and Children collections:
Just an observation, as I was looking how generate unique IDs client side for a similar reason. I found calling new Meteor.Collection.ObjectID() was returning a object in the form 'ObjectID("abc...")'. By assigning Meteor.Collection.ObjectID()._str to _id, I got string as 'abc...' instead, which is what I wanted.
I hope this helps, and I'd be curious to know if anyone has a better way of handling this?
Jason
Avoid using the _str because it can change in the future. Use this:
new Meteor.Collection.ObjectID().toHexString() or
new Meteor.Collection.ObjectID().valueOf()
You can also use the official random package:
Random.id()