I have a collection of people:
{
name: Juan,
age: 21
}
and now , I want to achieve the following:
{
name: Juan,
age: 21,
name_reply:Juan
}
I have tried using:
db.people.updateMany(
{"name_reply":null},
[{$set:{name_reply:"$name"}}]
);
but the following appears.
Expected type object but found array.
How could I update a mongo field using the value of another field?
db.collection.update({
"name_reply": null
},
[
{
"$set": {
"name_reply": "$name"
}
}
],
{
multi: true
})
But indeed this is only for mongodb version >=4.2 where you can provide aggregation pipeline to the update query
playground
for earlier versions you can check this answer here
something like this could do the job most probably:
db.collection.find({"name_reply":null}).snapshot().forEach(
function (doc) {
doc.name_reply = doc.name;
db.collection.save(doc);
}
);
Related
I have query in MongoDB for which I'm trying to upsert an inner nested attribute that contains a dot(.) in the key. E.g. a document might look something like: (below is a fictitious example just to highlight the constraint I'm facing.)
const person = {
name: 'Peter',
address: {
'NY.postalCode': 12345,
'CA.postalCode': 23456,
}
}
However, when I try to update one of the nested attribute in address with the below $set operation, I get an additional object NY under address and its subKey postalCode as a result, instead of the flattened attribute within address.
await Person.findByIdAndUpdate(id, {
$set: {
'address.NY.postalCode': 98765,
}
}, { new: true });
// Output
{
name: 'Peter',
address: {
'NY.postalCode': 12345,
'CA.postalCode': 23456,
NY: {
postalCode: 98765,
}
}
}
I've tried using the escape character for dot (\u002e), but get the same output. Also, I have seen some new features for setting fields but only in Mongo v5: https://www.mongodb.com/docs/manual/reference/operator/aggregation/setField/#mongodb-expression-exp.-setField. However, we're using Mongo v4.2 and would not be able to upgrade until a while later.
Would like to check if there are any means to $set nested attributes in address that don't completely replace the address object? i.e. to be able to specifically upsert an inner attribute within address object?
For example, is it possible to use the aggregation framework to workaround this?
I've tried something like the below, but it didn't work - not sure if its something that I did wrong or its probably not possible to use the aggregation pipeline..
Person.aggregate([
{
$match: {
_id: id,
},
},
{
$replaceRoot: { newRoot: {
$mergeObjects: [
'$$ROOT.address',
{
'NY.postalCode': 98765,
},
],
} },
},
]);
For your scenario, you need to achieve the update with aggregation pipeline.
Use $literal to escape the field name with dot.
Via $mergeObjects to merge current address object with { NY.postalCode': 98765 }.
db.collection.update({
"_id": ObjectId("5a934e000102030405000000")
},
[
{
$set: {
"address": {
$mergeObjects: [
"$address",
{
$literal: {
"NY.postalCode": 98765
}
}
]
}
}
}
],
{
new: true
})
Demo # Mongo Playground
I would like to update each elements (object) in an array of a company.
Here my actual data :
{
_id: ObjectId("60d31024860ce0400b586111")
contracts:
[
{
name: 1.pdf
url: "https://someurl"
createdAt: 2021-06-23T10:42:44.594+00:00
}
{
name: 2.pdf
url: "https://someurl"
}
{
name: 3.pdf
url: "https://someurl"
}
]
}
I would like to add a defined date on each object (in contracts) that has no "updatedAt" key.
Here what I tried :
db.companies.update({ _id: ObjectId("60d31024860ce0400b586111"),"contracts.createdAt": { $exists: false } },{ $set: { "contracts.$.createdAt": "test" } })
but I got this error :
"The positional operator did not find the match needed from the query."
I have also tried this and it works, but I don't wanna query by file name. I just wanna add "createdAt" on each elements found that has no "createdAt"
db.companies.update({ "contracts.name": "2.pdf" },{ $set: { "contracts.$.createdAt": "atest" } })
I think you need to use the filtered position operator:
$ - updates the first matched array element
$[] - updates all the matched elements with a specific condition
The specific condition is mentioned in the arrayFilters key.
db.students.update(
{ },
{ $set: { "contracts.$[element].createdAt" : "atest"} },
{ multi: true,
arrayFilters: [ { "element.createdAt": { $exists: false } } ]
}
)
multi - true is to apply the operation on all the matching documents.
Also notice, how the first query parameter is empty, which means the query runs for all documents. I used it based on the second query you wrote but you can also add in an ObjectID query there.
This error happens when I tried to update upsert item:
Updating the path 'x' would create a conflict at 'x'
Field should appear either in $set, or in $setOnInsert. Not in both.
I had the same problem while performing an update query using PyMongo.
I was trying to do:
> db.people.update( {'name':'lmn'}, { $inc : { 'key1' : 2 }, $set: { 'key1' : 5 }})
Notice that here I'm trying to update the value of key1 from two MongoDB Update Operators.
This basically happens when you try to update the value of a same key with more than one MongoDB Update Operators within the same query.
You can find a list of Update Operators over here
If you pass the same key in $set and in $unset when updating an item, you will get that error.
For example:
const body = {
_id: '47b82d36f33ad21b90'
name: 'John',
lastName: 'Smith'
}
MyModel.findByIdAndUpdate(body._id, { $set: body, $unset: {name: 1}})
// Updating the path 'name' would create a conflict at 'name'
You cannot have the same path referenced more than once in an update. For example, even though the below would result in something logical, MongoDB will not allow it.
db.getCollection("user").updateOne(
{_id: ...},
{$set: {'address': {state: 'CA'}, 'address.city' : 'San Diego'}}
)
You would get the following error:
Updating the path 'address.city' would create a conflict at 'address'
db.products.update(
{ _id: 1 },
{
$set: { item: "apple" },
$setOnInsert: { defaultQty: 100 }
},
{ upsert: true }
)
Below is the key explanation to the issue:
MongoDB creates a new document with _id equal to 1 from the
condition, and then applies the $set AND $setOnInsert operations to
this document.
If you want a field value is set or updated regardless of insertion or update, use it in $set. If you want it to be set only on insertion, use it in $setOnInsert.
Here is the example: https://docs.mongodb.com/manual/reference/operator/update/setOnInsert/#example
Starting from MongoDB 4.2 you can use aggregate pipelines in update:
db.your_collection.update({
_id: 1
},
[{
$set:{
x_field: {
$cond: {
if: {$eq:[{$type:"$_id"} , "missing"]},
then: 'upsert value', // it's the upsert case
else: '$x_field' // it's the update case
}
}
}
}],
{
upsert: true
})
db.collection.bulkWrite() also supports it
With the Ruby library at least, it's possible to get this error if you have the same key twice, once as a symbol and once as a string:
db.getCollection("user").updateOne(
{_id: ...},
{$set: {'name': "Horse", name: "Horse"}}
)
I recently had the same issue while using the query below.
TextContainer.findOneAndUpdate({ blockId: req.params.blockId, 'content._id': req.params.noteId }, { $set: { 'content.note': req.body.note } }, { upsert: true, new: true })
When i have changed 'content.note' to 'content.$.note' it has been fixed. So my final query is :
TextContainer.findOneAndUpdate({ blockId: req.params.blockId, 'content._id': req.params.noteId }, { $set: { 'content.$.note': req.body.note } }, { upsert: true, new: true })
I am have manually created an object in a Mongo collection:
{
"messages": [
{
"url":"http://test.test.com",
"message":"test message"
}
],
....other properties
}
I would like to add an _id:ObjectId() to each item of my messages array and for each document in the collection.
I tried:
collection.update({}, {
$set: {
'messages.$._id': ObjectId(),
},
}, { multi: true }
but this is not working. The Id is getting added when I add new ones going through Mongoose, but these were manually entered into mongo. Any help is appreciated.
Your syntax is correct, but in order to use the $ positional operator the array field must appear as part of the query document, check in documentation.
Try this:
db.collection.update({messages: {$exists: true }},
{$set: { 'messages.$._id': ObjectId() } },
{multi: true}
)
What I'm trying to do is pretty straightforward, but I can't find out how to give one field the value of another.
I simply want to update one field with the character count of another.
db.collection.update({$exists:true},{$set : {field1 : field2.length}})
I've tried giving it dot notation
db.collection.update({$exits:true},{$set : {field1: "this.field2.length"}})
As well as using javascript syntax
db.collection.update({$exits:true},
{$set : {field1: {$where : "this.field2.length"}})
But just copied the string and got a "notOkforstorage" respectively. Any help?
Update:
I only get the "notOkforStorage" when I query by ID:
db.collection.update({_id:ObjectID("38289842bbb")},
{$set : {field1: {$where :"this.field2.length"}}})
Try the following code:
db.collection.find(your_querry).forEach(function(doc) {
doc.field1 = doc.field2.length;
db.collection.save(doc);
});
You can use your_querry to select only part of the original collection do perform an update. If you want to process an entire collection, use your_querry = {}.
If you want all operations to be atomic, use update instead of save:
db.collection.find( your_querry, { field2: 1 } ).forEach(function(doc) {
db.collection.update({ _id: doc._id },{ $set: { field1: doc.field2.length } } );
});
Starting Mongo 4.2, db.collection.update() can accept an aggregation pipeline, finally allowing the update/creation of a field based on another field:
// { "_id" : ObjectId("5e84c..."), "field1" : 12, "field2" : "world" }
db.collection.update(
{ "_id" : ObjectId("5e84c...") },
[{ $set: { field1: { $strLenCP: "$field2" } } }]
)
// { "_id" : ObjectId("5e84c..."), "field1" : 5, "field2" : "world" }
The first part {} is the match query, filtering which documents to update.
The second part [{ $set: { field1: { $strLenCP: "$field2" } } }] is the update aggregation pipeline (note the squared brackets signifying the use of an aggregation pipeline). $set is a new aggregation operator and an alias for $addFields. Any aggregation operator can be used within the $set stage; in our case $strLenCP which provides the length of field2.
As far I know the easiest way is the read and write aproach:
//At first, get/prepare your new value:
var d= db.yourColl.fetchOne({....});
d.field1== d.field2.length;
// then update with your new value
db.yourColl.save(d);
Your are using exists in the wrong way.
Syntax: { field: { $exists: <boolean> } }
You use of $where is also incorrect
Use the $where operator to pass either a string containing a JavaScript expression or a full JavaScript function to the query system
db.myCollection.find( { $where: "this.credits == this.debits" } );
db.myCollection.find( { $where: "obj.credits == obj.debits" } );
db.myCollection.find( { $where: function() { return (this.credits == this.debits) } } );
db.myCollection.find( { $where: function() { return obj.credits == obj.debits; } } );
I think you should use Map-Reduce for what you are trying to do.