Related
What is the difference between the UpdateOne() and the findOneAndUpdate() methods in Mongo DB?
I can't seem o understand their differences. Would appreciate it if a demonstrative example using UpdateOne() and findOneAndUpdate could be used.
Insert a document in an otherwise empty collection using the mongo-shell to start:
db.users.insertOne({name: "Jack", age: 11})
UpdateOne
db.users.updateOne({name: "Jack"}, {$set: {name: "Joe"}})
This operation returns an UpdateResult.
{ acknowledged: true,
insertedId: null,
matchedCount: 1,
modifiedCount: 1,
upsertedCount: 0 }
FindOneAndUpdate
db.users.findOneAndUpdate({name: "Joe"}, {$set: {name: "Jill"}})
This operation returns the document that was updated.
{ _id: ObjectId("62ecf94510fc668e92f3cecf"),
name: 'Joe',
age: 11 }
FindOneAndUpdate is preferred when you have to update a document and fetch it at the same time.
If you need to return the New Document instead of the original document, you can use one of these ways:
db.users.findOneAndUpdate(
{name: "Joe"},
{$set: {name: "Jill"}},
{returnDocument: "after"}
)
returnDocument: "before" --> returns the original document (default).
returnDocument: "after" --> returns the updated document.
Or
db.users.findOneAndUpdate(
{name: "Joe"},
{$set: {name: "Jill"}},
{returnNewDocument: true}
)
returnNewDocument: false --> returns the original document (default).
returnNewDocument: true --> returns the updated document.
Note: If both options are set (returnDocument and returnNewDocument), returnDocument takes precedence.
I'd like to be able to pull a document by id from a triple nested array of documents. DB looks something like this:
[{
type: "Foods",
fruit: [{
name: "Apple",
kinds: [{
name: "Red Delicious"
details: [{
_id: ObjectId("123123123"),
colors: ["red", "yellow"]
}]
}]
}]
}]
I'd like to be able to pull the document with the _id: 123123123. I've tried many different ways, but it always says it matches, but won't modify the document.
I've tried:
db.stuff.update({}, {$pull: {fruits: {kinds: {details: {_id: "123123123"}}}}}),
db.stuff.update({}, {$pull: {"fruits.kinds.details' : {_id: "123123123"}}}),
db.stuff.update({}, {$pull: {"fruits.$[].kinds.$[].details' : {_id: "123123123"}}})
But everytime it matches, but won't delete the document.
Please help.
The last attempt is correct however you need to fix two things: fruit instead of fruit (according to your sample data) and types needs to match so you have to convert string to ObjectId
db.stuff.update({}, {$pull: {"fruit.$[].kinds.$[].details' : {_id: mongoose.Types.ObjectId("123123123")}}})
I'm currently working on a matching algorithm that calculates a score between two differents products lists.
I'm using mongodb aggregations to add a matching-score field calculated with differents arguments. Actually, the algorithm needs to know the position of each product in the list. So I thought to dynamically add a position field on each product to use it later.
I don't know which mongodb aggregation operator I have to use. Maybe someone can help me ?
Here is my list model :
const listSchema = mongoose.Schema({
type: { type: mongoose.Schema.Types.ObjectId, ref: "ListType", required: true },
links: [{
brand: { type: mongoose.Schema.Types.ObjectId, ref: "Brand", required: true },
work: { type: mongoose.Schema.Types.ObjectId, ref: "Product" },
}],
associatedUser: { type: mongoose.Schema.Types.ObjectId, ref: "User", required: true }
}, { versionKey: false });
In advance thank you,
Pierre
One method is to use the $reduce operator, which can be done in an aggregation pipeline, or as of MongoDB 4.2 in an update.
This example replaces an 'arrayField' containing
["Hello","World"]
with an array of objects like
[{index:0,value:"Hello"},{index:1,value:"World"}]
db.collection.update({},[{$set:{
arrayField:{
$reduce:{
input:"$arrayField",
initialValue:[],
in:{ $push:[
"$$value",
{index:{$size:"$$value"},
value:"$$this"}
]}
}
}
}}])
{
name: 'book',
tags: {
words: ['abc','123'],
lat: 33,
long: 22
}
}
Suppose this is a document. How do I remove "words" completely from all the documents in this collection? I want all documents to be without "words":
{
name: 'book',
tags: {
lat: 33,
long: 22
}
}
Try this: If your collection was 'example'
db.example.update({}, {$unset: {words:1}}, false, true);
Refer this:
http://www.mongodb.org/display/DOCS/Updating#Updating-%24unset
UPDATE:
The above link no longer covers '$unset'ing. Be sure to add {multi: true} if you want to remove this field from all of the documents in the collection; otherwise, it will only remove it from the first document it finds that matches. See this for updated documentation:
https://docs.mongodb.com/manual/reference/operator/update/unset/
Example:
db.example.update({}, {$unset: {words:1}} , {multi: true});
In the beginning, I did not get why the question has a bounty (I thought that the question has a nice answer and there is nothing to add), but then I noticed that the answer which was accepted and upvoted 15 times was actually wrong!
Yes, you have to use $unset operator, but this unset is going to remove the words key which does not exist for a document for a collection. So basically it will do nothing.
So you need to tell Mongo to look in the document tags and then in the words using dot notation. So the correct query is.
db.example.update(
{},
{ $unset: {'tags.words':1}},
false, true
)
Just for the sake of completion, I will refer to another way of doing it, which is much worse, but this way you can change the field with any custom code (even based on another field from this document).
db.example.updateMany({},{"$unset":{"tags.words":1}})
We can also use this to update multiple documents.
db.collection.updateMany({}, {$unset: {"fieldName": ""}})
updateMany requires a matching condition for each document, since we are passing {} it is always true. And the second argument uses $unset operator to remove the required field in each document.
To remove or delete field in MongoDB
For single Record
db.getCollection('userData').update({}, {$unset: {pi: 1}})
For Multi Record
db.getCollection('userData').update({}, {$unset: {pi: 1}}, {multi: true})
Starting in Mongo 4.2, it's also possible to use a slightly different syntax:
// { name: "book", tags: { words: ["abc", "123"], lat: 33, long: 22 } }
db.collection.updateMany({}, [{ $unset: ["tags.words"] }])
// { name: "book", tags: { lat: 33, long: 22 } }
Since the update method can accept an aggregation pipeline (note the squared brackets signifying the use of an aggregation pipeline), it means the $unset operator used here is the aggregation one (as opposed to the "query" one), whose syntax takes an array of fields.
The solution for PyMongo (Python mongo):
db.example.update({}, {'$unset': {'tags.words':1}}, multi=True);
I was trying to do something similar to this but instead remove the column from an embedded document. It took me a while to find a solution and this was the first post I came across so I thought I would post this here for anyone else trying to do the same.
So lets say instead your data looks like this:
{
name: 'book',
tags: [
{
words: ['abc','123'],
lat: 33,
long: 22
}, {
words: ['def','456'],
lat: 44,
long: 33
}
]
}
To remove the column words from the embedded document, do this:
db.example.update(
{'tags': {'$exists': true}},
{ $unset: {'tags.$[].words': 1}},
{multi: true}
)
or using the updateMany
db.example.updateMany(
{'tags': {'$exists': true}},
{ $unset: {'tags.$[].words': 1}}
)
The $unset will only edit it if the value exists but it will not do a safe navigation (it wont check if tags exists first) so the exists is needed on the embedded document.
This uses the all positional operator ($[]) which was introduced in version 3.6
To Remove a field you can use this command(this will be applied to all the documents in the collection) :
db.getCollection('example').update({}, {$unset: {Words:1}}, {multi: true});
And to remove multiple fields in one command :
db.getCollection('example').update({}, {$unset: {Words:1 ,Sentences:1}}, {multi: true});
Because I kept finding this page when looking for a way to remove a field using MongoEngine, I guess it might be helpful to post the MongoEngine way here too:
Example.objects.all().update(unset__tags__words=1)
In mongoDB shell this code might be helpful:
db.collection.update({}, {$unset: {fieldname: ""}} )
By default, the update() method updates a single document. Set the Multi Parameter to update all documents that match the query criteria.
Changed in version 3.6.
Syntax :
db.collection.update(
<query>,
<update>,
{
upsert: <boolean>,
multi: <boolean>,
writeConcern: <document>,
collation: <document>,
arrayFilters: [ <filterdocument1>, ... ]
}
)
Example :
db.getCollection('products').update({},{$unset: {translate:1, qordoba_translation_version:1}}, {multi: true})
In your example :
db.getCollection('products').update({},{$unset: {'tags.words' :1}}, {multi: true})
And for mongomapper,
Document: Shutoff
Field to remove: shutoff_type
Shutoff.collection.update( {}, { '$unset' => { 'shutoff_type': 1 } }, :multi => true )
It's worth mentioning, if you are using Typegoose/Mongoose your field needs to be declared in your model otherwise $unset will silently fail.
After a refactoring of a database this caught me unaware. The redundant fields were no longer in my model and I was running an $unset but nothing was happening.
So if you are doing some refactoring make sure you $unset your redundant fields before removing them from the model.
{
name: 'book',
tags: {
words: ['abc','123'],
lat: 33,
long: 22
}
}
Ans:
db.tablename.remove({'tags.words':['abc','123']})
Checking if "words" exists and then removing from the document
db.users.update({"tags.words" :{$exists: true}},
{$unset:{"tags.words":1}},false,true);
true indicates update multiple documents if matched.
you can also do this in aggregation by using project at 3.4
{$project: {"tags.words": 0} }
To reference a package and remove various "keys",
try this
db['name1.name2.name3.Properties'].remove([
{
"key" : "name_key1"
},
{
"key" : "name_key2"
},
{
"key" : "name_key3"
}
)]
{
name: 'book',
tags: {
words: ['abc','123'],
lat: 33,
long: 22
}
}
Suppose this is a document. How do I remove "words" completely from all the documents in this collection? I want all documents to be without "words":
{
name: 'book',
tags: {
lat: 33,
long: 22
}
}
Try this: If your collection was 'example'
db.example.update({}, {$unset: {words:1}}, false, true);
Refer this:
http://www.mongodb.org/display/DOCS/Updating#Updating-%24unset
UPDATE:
The above link no longer covers '$unset'ing. Be sure to add {multi: true} if you want to remove this field from all of the documents in the collection; otherwise, it will only remove it from the first document it finds that matches. See this for updated documentation:
https://docs.mongodb.com/manual/reference/operator/update/unset/
Example:
db.example.update({}, {$unset: {words:1}} , {multi: true});
In the beginning, I did not get why the question has a bounty (I thought that the question has a nice answer and there is nothing to add), but then I noticed that the answer which was accepted and upvoted 15 times was actually wrong!
Yes, you have to use $unset operator, but this unset is going to remove the words key which does not exist for a document for a collection. So basically it will do nothing.
So you need to tell Mongo to look in the document tags and then in the words using dot notation. So the correct query is.
db.example.update(
{},
{ $unset: {'tags.words':1}},
false, true
)
Just for the sake of completion, I will refer to another way of doing it, which is much worse, but this way you can change the field with any custom code (even based on another field from this document).
db.example.updateMany({},{"$unset":{"tags.words":1}})
We can also use this to update multiple documents.
db.collection.updateMany({}, {$unset: {"fieldName": ""}})
updateMany requires a matching condition for each document, since we are passing {} it is always true. And the second argument uses $unset operator to remove the required field in each document.
To remove or delete field in MongoDB
For single Record
db.getCollection('userData').update({}, {$unset: {pi: 1}})
For Multi Record
db.getCollection('userData').update({}, {$unset: {pi: 1}}, {multi: true})
Starting in Mongo 4.2, it's also possible to use a slightly different syntax:
// { name: "book", tags: { words: ["abc", "123"], lat: 33, long: 22 } }
db.collection.updateMany({}, [{ $unset: ["tags.words"] }])
// { name: "book", tags: { lat: 33, long: 22 } }
Since the update method can accept an aggregation pipeline (note the squared brackets signifying the use of an aggregation pipeline), it means the $unset operator used here is the aggregation one (as opposed to the "query" one), whose syntax takes an array of fields.
The solution for PyMongo (Python mongo):
db.example.update({}, {'$unset': {'tags.words':1}}, multi=True);
I was trying to do something similar to this but instead remove the column from an embedded document. It took me a while to find a solution and this was the first post I came across so I thought I would post this here for anyone else trying to do the same.
So lets say instead your data looks like this:
{
name: 'book',
tags: [
{
words: ['abc','123'],
lat: 33,
long: 22
}, {
words: ['def','456'],
lat: 44,
long: 33
}
]
}
To remove the column words from the embedded document, do this:
db.example.update(
{'tags': {'$exists': true}},
{ $unset: {'tags.$[].words': 1}},
{multi: true}
)
or using the updateMany
db.example.updateMany(
{'tags': {'$exists': true}},
{ $unset: {'tags.$[].words': 1}}
)
The $unset will only edit it if the value exists but it will not do a safe navigation (it wont check if tags exists first) so the exists is needed on the embedded document.
This uses the all positional operator ($[]) which was introduced in version 3.6
To Remove a field you can use this command(this will be applied to all the documents in the collection) :
db.getCollection('example').update({}, {$unset: {Words:1}}, {multi: true});
And to remove multiple fields in one command :
db.getCollection('example').update({}, {$unset: {Words:1 ,Sentences:1}}, {multi: true});
Because I kept finding this page when looking for a way to remove a field using MongoEngine, I guess it might be helpful to post the MongoEngine way here too:
Example.objects.all().update(unset__tags__words=1)
In mongoDB shell this code might be helpful:
db.collection.update({}, {$unset: {fieldname: ""}} )
By default, the update() method updates a single document. Set the Multi Parameter to update all documents that match the query criteria.
Changed in version 3.6.
Syntax :
db.collection.update(
<query>,
<update>,
{
upsert: <boolean>,
multi: <boolean>,
writeConcern: <document>,
collation: <document>,
arrayFilters: [ <filterdocument1>, ... ]
}
)
Example :
db.getCollection('products').update({},{$unset: {translate:1, qordoba_translation_version:1}}, {multi: true})
In your example :
db.getCollection('products').update({},{$unset: {'tags.words' :1}}, {multi: true})
And for mongomapper,
Document: Shutoff
Field to remove: shutoff_type
Shutoff.collection.update( {}, { '$unset' => { 'shutoff_type': 1 } }, :multi => true )
It's worth mentioning, if you are using Typegoose/Mongoose your field needs to be declared in your model otherwise $unset will silently fail.
After a refactoring of a database this caught me unaware. The redundant fields were no longer in my model and I was running an $unset but nothing was happening.
So if you are doing some refactoring make sure you $unset your redundant fields before removing them from the model.
{
name: 'book',
tags: {
words: ['abc','123'],
lat: 33,
long: 22
}
}
Ans:
db.tablename.remove({'tags.words':['abc','123']})
Checking if "words" exists and then removing from the document
db.users.update({"tags.words" :{$exists: true}},
{$unset:{"tags.words":1}},false,true);
true indicates update multiple documents if matched.
you can also do this in aggregation by using project at 3.4
{$project: {"tags.words": 0} }
To reference a package and remove various "keys",
try this
db['name1.name2.name3.Properties'].remove([
{
"key" : "name_key1"
},
{
"key" : "name_key2"
},
{
"key" : "name_key3"
}
)]