My structure is something like this:
{
"_id": "13hu13o13uuo1",
"profiles": {
"1": [1,2,3],
"847891": [3, 4],
..
}
}
"profiles" is an "object-array"/dictionary that has dynamic keys and their values are arrays.
How can I update all profile elements, inserting, let's say, 11 in every array?
Version: Mongo 4.2.3
While the syntax for the other answer is technically correct, I recommend not using the aggregation pipeline $merge approach for most usecases. The main reason is that such a pipeline is not atomic.
You can simply execute the exact same logic using the aggregation pipeline update feature, hence gaining the atomic property of the update operations in Mongo.
Here's how this looks:
db.collection.updateMany(
{},
[
{
"$set": {
"profiles": {
"$arrayToObject": {
"$map": {
"input": {
"$objectToArray": "$profiles"
},
"as": "element",
"in": {
k: "$$element.k",
v: {
"$concatArrays": [
"$$element.v",
[
11
]
]
}
}
}
}
}
}
}
])
Mongo Playground
Related
Array field in collection:
"fruits": [ "fruits": [ "fruits": [
{"fruit1": "banana"}, {"fruit2": "apple"}, {"fruit3": "pear"},
{"fruit2": "apple"}, {"fruit4": "orange"}, {"fruit2": "apple"},
{"fruit3": "pear"}, {"fruit1": "banana"}, {"fruit4": "orange"},
{"fruit4": "orange"} {"fruit3": "pear"} {"fruit1": "banana"}
]
I need to find those documents in collections, where "banana" signed before "apple". Does mongodb allows to compare elements in array just like :
if (fruits.indexOf('banana') < fruits.indexOf('apple')) return true;
Or maybe there is any other method to get result i need?
MongoDB's array query operations do not support any positional search as you want.
You can, however, write a $where query to do what you want:
db.yourCollection.find({
$where: function() {
return (this.fruits.indexOf('banana') < this.fruits.indexOf('apple'))
}
})
Be advised though, you won't be able to use indexes here and the performance will be a problem.
Another approach you can take is to rethink the database design, if you can specify what it is you're trying to build, someone can give you specific advise.
One more approach: pre-calculate the boolean value before persisting to DB as a field and query on true / false.
Consider refactoring your schema if possible. The dynamic field names(i.e. fruit1, fruit2...) make it unnecessarily complicated to construct a query. Also, if you require frequent queries by array index, you should probably store your array entries in individual documents with some sort keys to facilitate sorting with index.
Nevertheless, it is achievable through $unwind and $group the documents again. With includeArrayIndex clause, you can get the index inside array.
db.collection.aggregate([
{
"$unwind": {
path: "$fruits",
includeArrayIndex: "idx"
}
},
{
"$addFields": {
fruits: {
"$objectToArray": "$fruits"
}
}
},
{
"$addFields": {
"bananaIdx": {
"$cond": {
"if": {
$eq: [
"banana",
{
$first: "$fruits.v"
}
]
},
"then": "$idx",
"else": "$$REMOVE"
}
},
"appleIdx": {
"$cond": {
"if": {
$eq: [
"apple",
{
$first: "$fruits.v"
}
]
},
"then": "$idx",
"else": "$$REMOVE"
}
}
}
},
{
$group: {
_id: "$_id",
fruits: {
$push: {
"$arrayToObject": "$fruits"
}
},
bananaIdx: {
$max: "$bananaIdx"
},
appleIdx: {
$max: "$appleIdx"
}
}
},
{
$match: {
$expr: {
$lt: [
"$bananaIdx",
"$appleIdx"
]
}
}
},
{
$unset: [
"bananaIdx",
"appleIdx"
]
}
])
Mongo Playground
My question is a combination of:
This question: Removing the array element in mongoDB based on the position of element
And this question: mongodb set object where key value dynamically changes
I know you can define the field (array) dynamically like this:
{ [arrayName]: { <condition> } }
But, I then want to remove a certain element in a dynamically defined array by specifying the position (which is also defined dynamically). In other words, the function that processes this query is coming in which two parameters: the array's name and the index of the element to remove.
The options given by the selected answer were the following:
Option 1, does not work (in general), adapted to my case this looks like:
{ $pull : { [arrayName] : { $gt: index-1, $lt: index+1 } } }
Option 2, I cannot use dynamically defined values in field selectors with quotation marks (as far as I am aware):
{ $pull : "[arrayName].[index]" }
or
{ $pull : "[arrayName].$": index }
Option 3, is different method but can't use it for the same reason:
{ $unset: { "[arrayName].[index]": 1 } } // Won't work
{ $pull: { [arrayName]: null } } // Would probably work
The only workarounds I can think of right now involve significantly changing the design which would be a shame. Any help is appreciated!
PS: I'm using mongoose as a driver on the latest version as of today (v6.3.5) and MongoDB version 5.0.8
On Mongo version 4.2+ You can use pipelined updates to achieve this, you can get it done in multiple ways, here is what I consider the easiest two ways:
using $slice and $concatArrays to remove a certain element:
db.collection.update({},
[
{
$set: {
[arrayName]: {
$concatArrays: [
{
$slice: [
`$${arrayName}`,
index,
]
},
{
$slice: [
`$${arrayName}`,
index + 1,
{
$size: `$${arrayName}`
}
]
}
]
}
}
}
])
Mongo Playground
using $filter and $zip to filter out based on index:
db.collection.updateOne(
{},
[
{
"$set": {
[arrayName]: {
$map: {
input: {
$filter: {
input: {
$zip: {
inputs: [
{
$range: [
0,
{
$size: `$${arrayName}`
}
]
},
`$${arrayName}`
]
}
},
cond: {
$ne: [
{
"$arrayElemAt": [
"$$this",
0
]
},
index
]
}
}
},
in: {
$arrayElemAt: [
"$$this",
1
]
}
}
}
}
}
])
Alternatively you can just prepare
Suppose I have a document that looks like this:
{
"id": 1,
"entries": [
{
"id": 100,
"urls": {
"a": "url-a",
"b": "url-b",
"c": "url-c"
},
"revisions": []
}
]
}
I am trying to add a new object to the revisions array that contains its own urls field. Two of the fields should be copied from the entry's urls, while the last one will be new. The result should look like this:
{
"id": 1,
"entries": [
{
"id": 100,
"urls": {
"a": "url-a",
"b": "url-b",
"c": "url-c"
},
"revisions": [
{
"id": 1000,
"urls": {
"a": "url-a", <-- copied
"b": "url-b", <-- copied
"c": "some-new-url" <-- new
}
}
]
}
]
}
I am on MongoDB 4.2+, so I know I can use $property on the update query to reference values. However, this does not seem to be working as I expect:
collection.updateOne(
{
id: 1,
"enntries.id": 100
},
{
$push: {
"entries.$.revisions": {
id: 1000,
urls: {
"a": "$entries.$.urls.a",
"b": "$entries.$.urls.b",
"c": "some-new-url"
}
}
}
}
);
The element gets added to the array, but all I see for the url values is the literal $entries.$.urls.a. value I suspect the issue is with combining the reference with selecting a specific positional array element. I have also tried using $($entries.$.urls.a), with the same result.
How can I make this work?
Starting from MongoDB version >= 4.2 you can use aggregation pipeline in updates which means your update part of query will be wrapped in [] where you can take advantage of executing aggregation in query & also use existing field values in updates.
Issue :
Since you've not wrapped update part in [] to say it's an aggregation pipeline, .updateOne() is considering "$entries.$.urls.a" as a string. I believe you'll not be able to use $ positional operator in updates which use aggregation pipeline.
Try below query which uses aggregation pipeline :
collection.updateOne(
{
id: 1,
"entries.id": 100 /** "entries.id" is optional but much needed to avoid execution of below aggregation for doc where `id :1` but no `"entries.id": 100` */,
}
[
{
$set: {
entries: {
$map: { // aggregation operator `map` iterate over array & creates new array with values.
input: "$entries",
in: {
$cond: [
{ $eq: ["$$this.id", 100] }, // `$$this` is current object in array iteration, if condition is true do below functionality for that object else return same object as is to array being created.
{
$mergeObjects: [
"$$this",
{
revisions: { $concatArrays: [ "$$this.revisions", [{ id: 1000, urls: { a: "$$this.urls.a", b: "$$this.urls.b", c: "some-new-url" } } ]] }
}
]
},
"$$this" // Returning same object as condition is not met.
]
}
}
}
}
}
]
);
$mergeObjects will replace existing revisions field in $$this (current) object with value of { $concatArrays: [ "$$this.revisions", { id: 1000, urls: { a: "$$this.urls.a", b: "$$this.urls.b", c: "some-new-url" } } ] }.
From the above field name revisions and as it being an array I've assumed there will multiple objects in that field & So we're using $concatArrays operator to push new objects into revisions array of particular entires object.
In any case, if your revisions array field does only contain one object make it as an object instead of array Or you can keep it as an array & use below query - We've removed $concatArrays cause we don't need to merge new object to existing revisions array as we'll only have one object every-time.
collection.update(
{
id: 1,
"entries.id": 100
}
[
{
$set: {
entries: {
$map: {
input: "$entries",
in: {
$cond: [
{ $eq: ["$$this.id", 100] },
{
$mergeObjects: [
"$$this",
{
revisions: [ { id: 1000, urls: { a: "$$this.urls.a", b: "$$this.urls.b", c: "some-new-url" } } ]
}
]
},
"$$this"
]
}
}
}
}
}
]
);
Test : Test your aggregation pipeline here : mongoplayground
Ref : .updateOne()
Note : If in any case .updateOne() throws in an error due to in-compatible client or shell, try this query with .update(). This execution of aggregation pipeline in updates helps to save multiple DB calls & can be much useful on arrays with less no.of elements.
In MongoDB, I have a movie collection that has an array of languages , e.g.
languages: [0:USA, 1: German, 2: French, ...etc]
The array values are not in any particular order.
How can I now update an array value based on some specific value? Let's say I want to update all "French" and replace it with "Francais" for the entire collection. How can I do that?
Use the positional $ operator which identifies the element in the languages array to update without explicitly specifying its position in the array i.e. instead of knowing the position in advance and updating the element as:
db.movies.updateMany(
{ "languages": "French" },
{ "$set": { "languages.2": "Francais" } }
)
you can just use the $ operator as:
db.movies.updateMany(
{ "languages": "French" },
{ "$set": { "languages.$": "Francais" } }
)
Alternatively using the aggregation pipeline for update operations:
db.movies.updateMany(
{ "languages": "French" },
[
{ "$set": {
"languages": {
"$map": {
"input": "$languages",
"in": {
"$cond": [
{ "$eq": ["$$this", "French"] },
"Francais",
"$$this"
]
}
}
}
} }
]
)
In case you have duplicate entries in your array like this:
"languages" : [
"USA",
"German",
"French",
"French"
]
You can use the following syntax to replace all occurrences starting with MongoDB v3.5.12 (documentation)
db.movies.updateMany(
{ "languages": "French" },
{ "$set": { "languages.$[filter]": "Francais" } },
{ "arrayFilters": [ { "filter": "French" } ] }
)
Strictly speaking, the { "languages": "French" } filter is not needed. It will, however, speed up things by leveraging an index on "languages" in case there is one. If that's not needed/wanted, passing a simple {} value as the first parameter works as well.
I'm using the following json to find results in a Cloudant
{
"selector": {
"$and": [
{
"type": {
"$eq": "sensor"
}
},
{
"v": {
"$eq": 2355
}
},
{
"$or": [
{
"p": "#401000103"
},
{
"p": "#401000114"
}
]
},
{
"t_max": {
"$gte": 1459554894
}
},
{
"t_min": {
"$lte": 1459509591
}
}
]
},
"fields": [
"_id",
"p"
],
"limit": 200
}
If I run this againt my cloudant database I get the following error:
{
"error": "unknown_error",
"reason": "function_clause",
"ref": 3379914628
}
If I remove one the $or elements I get the results for query.
(,{"p":"#401000114"})
Also i get a result if I replace #401000114 with #401000114 I get result.
But when I want to use both element I get the error code above.
Can anybody tell what this error_reason: function_clause mean?
error_reason: function_clause means there was a problem on the server, you should probably reach out to Cloudant Support and see if they can help you with your issue.
I had contact with the Cloudant support.
This is there answer:
The issue affects Cloudant generally
It affects both mult-tenant and dedicated clusters.
There are working on the sollution.
A workaround is in the array to which the $or operator applies has two elements, you can get the correct result by repeating one of the items in the array.