I am trying to update an Array object based on a condition. Following is my scenario :-
I want to update status from current to archive.
I have tried many things for hours but still no luck. Like this :-
db.user.update({
'injury._id': ObjectId("5374cb4d1e0386c02800006a"),
'injury.injurydata.locationaddressinjury': {
$elemMatch: {
'status': 'current'
}
}
}, {
$set: {
'injury.injurydata.locationaddressinjury.status': 'archive'
}
})
The picture made it hard to read the structure of your data. But I guess the update you are looking for would be something like this:
db.user.update({
'injury._id': ObjectId("5374cb4d1e0386c02800006a"),
'injury.injurydata.locationaddressinjury': {
$elemMatch: {
'status': 'current'
}
}
}, {
$set: {
'injury.injurydata.locationaddressinjury.$.status': 'archive'
}
});
The $ would refer to the element you found. While if you are looking for a way to update all element at one time. I'm afraid $elemMatch would just match the first element that satisfies your condition.
Related
I hate to risk asking a duplicate question, but perhaps this is different from Passing Variables to a MongoDB View which didn't have any clear solution.
Below is a query to find the country for IP Address 16778237. (Outside the scope of this query, there is a formula that turns an IPV4 address into a number.)
I was wondering if we could abstract away this query out of NodeJS code, and make a view, so the view could be called from NodeJS. But the fields ipFrom and ipTo are indexed to get the query to run fast against millions of documents in the collection, so we can't return all the rows to NodeJS and filter there.
In MSSQL maybe this would have to be a stored procedure, instead of a view. Just trying to learn what is possible in MongoDB. I know there are functions, which are written in JavaScript. Is that where I need to look?
db['ip2Locations'].aggregate(
{
$match:
{
$and: [
{
"ipFrom": {
$lte: 16778237
}
},
{
"ipTo": {
$gte: 16778237
}
},
{
"active": true
}
],
$comment: "where 16778237 between startIPRange and stopIPRange and the row is 'Active',sort by createdDateTime, limit to the top 1 row, and return the country"
}
},
{
$sort:
{
'createdDateTime': - 1
}
},
{
$project:
{
'countryCode': 1
}
},
{
$limit: 1
}
)
Part 2 - after more research and experimenting, I found this is possible and runs with success, but then see trying to make a view below this query.
var ipaddr = 16778237
db['ip2Locations'].aggregate(
{
$match:
{
$and: [
{
"ipFrom": {
$lte: ipaddr
}
},
{
"ipTo": {
$gte: ipaddr
}
},
{
"active": true
}
],
$comment: "where 16778237 between startIPRange and stopIPRange and the row is 'Active',sort by createdDateTime, limit to the top 1 row, and return the country"
}
},
{
$sort:
{
'createdDateTime': - 1
}
},
{
$project:
{
'countryCode': 1
}
},
{
$limit: 1
}
)
If I try to create a view with a "var" in it, like this;
db.createView("ip2Locations_vw-lookupcountryfromip","ip2Locations",[
var ipaddr = 16778237
db['ip2Locations'].aggregate(
I get error:
[Error] SyntaxError: expected expression, got keyword 'var'
In the link I provided above, I think the guy was trying to figure how the $$user-variables work (no example here: https://docs.mongodb.com/manual/reference/aggregation-variables/). That page refers to $let, but never shows how the two work together. I found one example here: https://www.tutorialspoint.com/mongodb-query-to-set-user-defined-variable-into-query on variables, but not $$variables. I'm
db.createView("ip2Locations_vw-lookupcountryfromip","ip2Locations",[
db['ip2Locations'].aggregate(
...etc...
"ipFrom": {
$lte: $$ipaddr
}
I tried ipaddr, $ipaddr, and $$ipaddr, and they all give a variation of this error:
[Error] ReferenceError: $ipaddr is not defined
In a perfect world, one would be able to do something like:
get['ip2Locations_vw-lookupcountryfromip'].find({$let: {'ipaddr': 16778237})
or similar.
I'm getting that it's possible with Javascript stored in MongoDB (How to use variables in MongoDB query?), but I'll have to re-read that; seems like some blogs were warning against it.
I have yet to find a working example using $$user-variables, still looking.
Interpretation
You want to query a view from some server side code, passing a variable to it.
Context
Can we use an external variable to recompute a View? Take the following pipeline:
var pipeline = [{ $group:{ _id:null, useless:{ $push:"$$NOW" } } }]
We can pass system variables using $$. We can define user variables too, but the user defined variables are made out of:
Collection Data
System Variables.
Also, respect to your Part2:
A variable var variable="what" will be computed only once. Redefine variable="whatever" makes no difference in the view, it uses "what".
Conclusion
Views can only be re-computed with system variables, or user variables dependant on those system variables or collection data.
Added an answer to the post you link too.
I've recently started using MongoDB using Mongoose (from NodeJS), but now I got stuck updating a subdocument in an array.
Let me show you...
I've set up my Restaurant in MongoDB like so:
_id: ObjectId("5edaaed8d8609c2c47fd6582")
name: "Some name"
tables: Array
0: Object
id: ObjectId("5ee277bab0df345e54614b60")
status: "AVAILABLE"
1: Object
id: ObjectId("5ee277bab0df345e54614b61")
status: "AVAILABLE"
As you can see a restaurant can have multiple tables, obviously.
Now I would like to update the status of a table for which I know the _id. I also know the _id of the restaurant that has the table.
But....I only want to update the status if we have the corresponding tableId and this table has the status 'AVAILABLE'.
My update statement:
const result = await Restaurant.updateOne(
{
_id: ObjectId("5edaaed8d8609c2c47fd6582"),
'tables._id': ObjectId("5ee277bab0df345e54614b61"),
'tables.status': 'AVAILABLE'
},
{ $set: { 'tables.$.status': 'CONFIRMED' } }
);
Guess what happens when I run the update-statement above?
It strangely updates the FIRST table (with the wrong table._id)!
However, when I remove the 'tables.status' filter from the query, it does update the right table:
const result = await Restaurant.updateOne(
{
_id: ObjectId("5edaaed8d8609c2c47fd6582"),
'tables._id': ObjectId("5ee277bab0df345e54614b61")
},
{ $set: { 'tables.$.status': 'CONFIRMED' } }
);
Problem here is that I need the status to be 'AVAILABLE', or else it should not update!
Can anybody point me in the wright direction with this?
according to the docs, the positional $ operator acts as a placeholder for the first element that matches the query document
so you are updating only the first array element in the document that matches your query
you should use the filtered positional operator $[identifier]
so your query will be something like that
const result = await Restaurant.updateOne(
{
_id: ObjectId("5edaaed8d8609c2c47fd6582"),
'tables._id': ObjectId("5ee277bab0df345e54614b61"),
'tables.status': 'AVAILABLE'
},
{
$set: { 'tables.$[table].status': 'CONFIRMED' } // update part
},
{
arrayFilters: [{ "table._id": ObjectId("5ee277bab0df345e54614b61"), 'table.status': 'AVAILABLE' }] // options part
}
);
by this way, you're updating the table element that has that tableId and status
hope it helps
My goal is to add a comment to my CommentFeed and while doing that I want to push that comment into my topComments field and also update the 'numOfComments' . I want to limit the topComments to only 3 comments (How would I even set that up?). And how do I take the previous value of numOfComments and add one to it?
CommentFeed.findOneAndUpdate(
{ _id: commentId },
{
$push: {
comments: {
text: req.body.text
},
$push: topComments:{text: req.body.text}, <--- Limit this somehow to only allow an array length of 3?
$set: numOfComments: ? , <---What kind of logic is used here?
}
},
{ new: true }
)
CommentFeed Schema
const CommentFeedSchema = new Schema({
topComments:[{text:{type:String}}],
numOfComments:{type:Number},
comments: [
text: { type: String, required: true }
]});
For the first issue (limiting the topComments array size) you can use the $slice operator. This has already been answered in other questions. But you might consider computing topComments from comments using the$slice operator in the projection argument:
CommentFeed.find( {}, { comments: { $slice: -3 } } )
For the second issue (updating a document using existing fields from that document), it is not something you can do in a simple findOneAndUpdate call. This was also discussed in other questions.
But you might consider computing numOfComments instead of updating it every time. You can do that with the $size operator of the aggregation framework:
CommentFeed.aggregate({$project: { numOfComments: { $size:"$comments" }}})
I'm trying to project out only the matched element of an array, in the updated version. But I'm getting the error: "MongoError: >1 field in obj: { _id: 0, lotes.$: 1 }"
If I remove 'new: true', it works. But then I have the doc before the update. And I would really like the updated version.
What's wrong? How can I fix it?
The Offer doc is something like:
{
_id
series: [ Serie ]
}
Serie structure is something like:
{
_id
public.available: Number
public.expDate: Date
}
I'm using Mongoose:
var query = {
'_id': offerId,
'series': {
$elemMatch: {
'_id': serieId,
'public.available': {$gt:0},
'public.expDate': {$gt: now}
}
}
};
var update = {
$inc: { 'series.$.public.available' : -1 }
};
var options = { // project out just the element found, updated
new:true,
select: {
'_id': 0,
'series.$': 1
}
};
Offers.findOneAndUpdate(query, update, options)
.then( element => {
...
}
For anyone else experiencing this error, it is also the most common error when trying to perform an illegal action such as trying to update a database element inside of a findOne request.
Making sure your request is correct, such as findOneAndUpdate should be your first port of call when you get this error.
As Anthony Winzlet pointed out in the links, there seems to be an issue with Mongoose, in which if you use 'new:true', you can't project out the $elemMatch.
So my solution was to keep using 'new:true' only, without projections. And reduce the array later on to get the $elemMatch:
.then( (result) => {
var aux = result.series.reduce((acu, serie, index) => {
if (serie._id == req.params.serieId) return index;
});
var element = result.series[aux];
}
I'm trying to update a sub document on an existing collection. I'm getting a MongoDB error message.
"MongoError: The positional operator did not find the match needed from the query. Unexpanded update: articleWords.$ [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.