I am trying to get a value in my mongoDB collection. I would like to get the title of a movie and the sales (nbSold) of this movie for the current month.
Here is how my data are stored :
"_id" : ObjectId("52e6a1aacf0b3b522a8a157a"),
"title" : "Pulp Fiction",
"sales" : [
{
"date" : ISODate("2013-11-01T00:00:00Z"),
"nbSold" : 6
},
{
"date" : ISODate("2013-12-01T00:00:00Z"),
"nbSold" : 2
}
]
I'm using mongoose and this is how I build my query for the december of 2013 :
var query = Movie.find({"title":"Pulp Fiction"}, "title sales.nbSold")
.where("sales.date")
.equals(new Date("2013-12-01"));
However, this is the output that I am receiving :
{ title: 'Pulp Fiction', sales: [ { nbSold: 6 }, { nbSold: 2 } ] }
I would like to have only the title associated with the nbSold of the current month (2 in my case). What is the correct way to do this ?
Thanks a lot for your help.
First off, you should close your where call. You should call .exec(callback) when you're done comparing, and you should be using select instead of equals along with $elemMatch. Try this:
var query = Movie.find({"title":"Pulp Fiction"}, "title sales.nbSold")
.where("sales.date")
.select({ sales: { $elemMatch: new Date("2013-12-01") }})
.exec(function(err, doc) {
return console.dir(doc);
});
You should also have a callback. I ran this on my machine, and it definitely works. I posted code earlier that wasn't quite right, but this does the trick. See the documentation for an example.
Also, I'd be concerned as to how you're seeing if the date matches. If the time is off in your Date object but the date matches, Mongo won't find a match. And I don't know exactly how it works in Mongo, but in JavaScript, you can't compare two Date objects directly for equality as they are both different objects with the same value, so you may come across that problem as well. See this post for an example on how to do it.
Related
I would like to preface this with saying that english is not my mother tongue, if any of my explanations are vague or don't make sense, please let me know and I will attempt to make them clearer.
I have a document containing some nested data. Currently product and customer are arrays, I would prefer to have them as straight up ObjectIDs.
{
"_id" : ObjectId("5bab713622c97440f287f2bf"),
"created_at" : ISODate("2018-09-26T13:44:54.431Z"),
"prod_line" : ObjectId("5b878e4c22c9745f1090de66"),
"entries" : [
{
"order_number" : "123",
"product" : [
ObjectId("5ba8a0e822c974290b2ea18d")
],
"customer" : [
ObjectId("5b86a20922c9745f1a6408d4")
],
"quantity" : "14"
},
{
"order_number" : "456",
"product" : [
ObjectId("5b878ed322c9745f1090de6c")
],
"customer" : [
ObjectId("5b86a20922c9745f1a6408d5")
],
"quantity" : "12"
}
]
}
I tried using the following query to update it, however that proved unsuccessful as Mongo didn't behave quite as I had expected.
db.Document.find().forEach(function(doc){
doc.entries.forEach(function(entry){
var entry_id = entry.product[0]
db.Document.update({_id: doc._id}, {$set:{'product': entry_id}});
print(entry_id)
})
})
With this query it sets product in the root of the object, not quite what I had hoped for. What I was hoping to do was to iterate through entries and change each individual product and customer to be only their ObjectId and not an array. Is it possible to do this via the mongo shell or do I have to look for another way to accomplish this? Thanks!
In order to accomplish your specified behavior, you just need to modify your query structure a bit. Take a look here for the specific MongoDB documentation on how to accomplish this. I will also propose an update to your code below:
db.Document.find().forEach(function(doc) {
doc.entries.forEach(function(entry, index) {
var productElementKey = 'entries.' + index + '.product';
var productSetObject = {};
productSetObject[productElementKey] = entry.product[0];
db.Document.update({_id: doc._id}, {$set: productSetObject});
print(entry_id)
})
})
The problem that you were having is that you were not updating the specific element within the entries array, but rather adding a new key to the top-level of the document named product. Generally, in order to set the value of an inner document within an array, you need to specify the array key first (entries in this case) and the inner document key second (product in this case). Since you are trying to set specific elements within the entries array, you need to also specify the index in your query object, I have specified above.
In order to update the customer key in the inner documents, simply switch out the product for customer in my above code.
You're trying to add a property 'product' directly into your document with this line
db.Document.update({_id: doc._id}, {$set:{'product': entry_id}});
Try to modify all your entries first, then update your document with this new array of entries.
db.Document.find().forEach(function(doc){
let updatedEntries = [];
doc.entries.forEach(function(entry){
let newEntry = {};
newEntry["order_number"] = entry.order_number;
newEntry["product"] = entry.product[0];
newEntry["customer"] = entry.customer[0];
newEntry["quantity"] = entry.quantity;
updatedEntries.push(newEntry);
})
db.Document.update({_id: doc._id}, {$set:{'entries': updatedEntries}});
})
You'll need to enumerate all the documents and then update the documents one and a time with the value store in the first item of the array for product and customer from each entry:
db.documents.find().snapshot().forEach(function (elem) {
elem.entries.forEach(function(entry){
db.documents.update({
_id: elem._id,
"entries.order_number": entry.order_number
}, {
$set: {
"entries.$.product" : entry.product[0],
"entries.$.customer" : entry.customer[0]
}
}
);
});
});
Instead of doing 2 updates each time you could possibly use the filtered positional operator to do all updates to all arrays items within one update query.
Currently in my database I have messages objects set up as the following.
{
"name" : "System",
"message" : "Sean Callahan has entered the room.",
"time" : 1406479167270,
"type" : "system_message",
"room" : "helloroom",
"_id" : "4yeHzhHAQmGJNtHww"
}
I want to basically migrate my data so that every message has a roomId that point it at the appropriate room. Currently this is done by the with the room attribute, which I know see the fault in my ways for various reasons.
My room objects are setup something like this.
{
"_id:" xxxxxxxxx
"room_name:" "testingroom"
}
So I was hoping there was a way to run a one-liner that would just add the correct roomId to every current message based on the current room attribute that is set
I was thinking something along the lines of..
db.messages.update({}, {$set: {roomId: db.rooms.findOne({room_name: room})._id}})
As of now, I am getting room is not defined, which makes perfect sense. But I can't seem to get it right, and this may just not be possible in a one-line query.
As you discovered, this isn't possible in a one-line query since you need to join data from two collections.
Here's an example of how to add the missing field in the mongo shell:
db.messages.find(
{ roomId: { $exists: false} }
).forEach(function(room) {
var roomId = db.rooms.findOne({room_name: room.room});
if (roomId._id) {
db.messages.update(
{ _id: room._id },
{ $set: { roomId: roomId._id }}
)
}
})
You could tidy this up with some error checking, and for updates on a large collection consider using the Bulk Update API (only available in MongoDB 2.6+).
I have a database of person documents. Each has a field named photos, which is an array of photo documents. I would like to add a new 'reviewed' flag to each of the photo documents and initialize it to false.
This is the query I am trying to use:
db.person.update({ "_id" : { $exists : true } }, {$set : {photos.reviewed : false} }, false, true)
However I get the following error:
SyntaxError: missing : after property id (shell):1
Is this possible, and if so, what am I doing wrong in my update?
Here is a full example of the 'person' document:
{
"_class" : "com.foo.Person",
"_id" : "2894",
"name" : "Pixel Spacebag",
"photos" : [
{
"_id" : null,
"thumbUrl" : "http://site.com/a_s.jpg",
"fullUrl" : "http://site.com/a.jpg"
},
{
"_id" : null,
"thumbUrl" : "http://site.com/b_s.jpg",
"fullUrl" : "http://site.com/b.jpg"
}]
}
Bonus karma for anyone who can tell me a cleaner why to update "all documents" without using the query { "_id" : { $exists : true } }
For those who are still looking for the answer it is possible with MongoDB 3.6 with the all positional operator $[] see the docs:
db.getCollection('person').update(
{},
{ $set: { "photos.$[].reviewed" : false } },
{ multi: true}
)
Is this possible, and if so, what am I doing wrong in my update?
No. In general MongoDB is only good at doing updates on top-level objects.
The exception here is the $ positional operator. From the docs: Use this to find an array member and then manipulate it.
However, in your case you want to modify all members in an array. So that is not what you need.
Bonus karma for anyone who can tell me a cleaner why to update "all documents"
Try db.coll.update(query, update, false, true), this will issue a "multi" update. That last true is what makes it a multi.
Is this possible,
You have two options here:
Write a for loop to perform the update. It will basically be a nested for loop, one to loop through the data, the other to loop through the sub-array. If you have a lot of data, you will want to write this is your driver of choice (and possibly multi-thread it).
Write your code to handle reviewed as nullable. Write the data such that if it comes across a photo with reviewed undefined then it must be false. Then you can set the field appropriately and commit it back to the DB.
Method #2 is something you should get used to. As your data grows and you add fields, it becomes difficult to "back-port" all of the old data. This is similar to the problem of issuing a schema change in SQL when you have 1B items in the DB.
Instead just make your code resistant against the null and learn to treat it as a default.
Again though, this is still not the solution you seek.
You can do this
(null, {$set : {"photos.reviewed" : false} }, false, true)
The first parameter is null : no specification = any item in the collection.
"photos.reviewed" should be declared as string to update subfield.
You can do like this:
db.person.update({}, $set:{name.surname:null}, false, true);
Old topic now, but this just worked fine with Mongo 3.0.6:
db.users.update({ _id: ObjectId("55e8969119cee85d216211fb") },
{ $set: {"settings.pieces": "merida"} })
In my case user entity looks like
{ _id: 32, name: "foo", ..., settings: { ..., pieces: "merida", ...} }
I have the following collection:
{
"Milestones" : [
{ "ActualDate" : null,
"Index": 0,
"Name" : "milestone1",
"TargetDate" : ISODate("2011-12-13T22:00:00Z"),
"_id" : ObjectId("4ee89ae7e60fc615c42e28d1")},
{ "ActualDate" : null,
"Index" : 0,
"Name" : "milestone2",
"TargetDate" : ISODate("2011-12-13T22:00:00Z"),
"_id" : ObjectId("4ee89ae7e60fc615c42e28d2") } ]
,
"Name" : "a", "_id" : ObjectId("4ee89ae7e60fc615c42e28ce")
}
I want to update definite documents: that have specified _id, List of Milestones._id and ActualDate is null.
I dotnet my code looks like:
var query = Query.And(new[] { Query.EQ("_id", ObjectId.Parse(projectId)),
Query.In("Milestones._id", new BsonArray(values.Select(ObjectId.Parse))),
Query.EQ("Milestones.ActualDate", BsonNull.Value) });
var update = Update.Set("Milestones.$.ActualDate", DateTime.Now.Date);
Coll.Update(query, update, UpdateFlags.Multi, SafeMode.True);
Or in native code:
db.Projects.update({ "_id" : ObjectId("4ee89ae7e60fc615c42e28ce"), "Milestones._id" : { "$in" : [ObjectId("4ee89ae7e60fc615c42e28d1"), ObjectId("4ee89ae7e60fc615c42e28d2"), ObjectId("4ee8a648e60fc615c41d481e")] }, "Milestones.ActualDate" : null },{ "$set" : { "Milestones.$.ActualDate" : ISODate("2011-12-13T22:00:00Z") } }, false, true)
But only the first item is being updated.
This is not possible in current moment. Flag multi in update means update of multiple root documents. Positional operator can match only one nested array item. There is such feature in mongodb jira. You can vote up and wait.
Current solution can be only load document, update as you wish and save back or multiple atomic update for each nested array id.
From documentation at mongodb.org:
Currently the $ operator only applies to the first matched item in the
query
As answered by Andrew Orsich, this is not possible for the moment, at least not as you wish. But loading the document, modifying the array then saving it back will work. The risk is that some other process could modify the array in the meantime, so you would overwrite its changes. To avoid this, you can use optimistic locking, especially if the array is not modified every second.
load the document, including a new attribute: milestones_version
modify the array as needed
save back to mongodb, but now add a query constraint on the milestones_version, and increment it:
db.Projects.findAndModify({
query: {
_id: your_project_id,
milestones_version: expected_milestones_version
},
update: {
$set: {
Milestones: modified_milestones
},
$inc: {
milestones_version: 1
}
},
new: 1
})
If another process modified the milestones array (and hence the milestones_version) before we did, then this command will do nothing and simply return null. We just need to reload the document and try again. If the array is not modified every second, then this will be very rare and will not have any impact on performance.
The main problem with this solution is that you have to edit every Project, one by one (no multi: true). You could still write a javascript function and have it run on the server though.
According to their JIRA page "This new feature is available starting with the MongoDB 3.5.12 development version, and included in the MongoDB 3.6 production version"
https://jira.mongodb.org/browse/SERVER-1243
I have the following collection for a user in a MongoDB:
{
"_id" : 1,
"facebook_id" : XX,
"name": "John Doe",
"points_snapshot" : [{
"unix_timestamp" : 1312300552,
"points" : 115
}, {
"unix_timestamp" : 1312330380,
"points" : 110
}, {
"unix_timestamp" : 1312331610,
"points" : 115
}]
}
Is it possible to write one query which by which I can get the user for id 1 along with the snapshots after a particular day. eg: 1312330300?
Basically limit the snapshots to X numbers matching some criteria?
So far, I have tried in C#:
Query.And(
Query.EQ("facebook_id", XX),
Query.GTE("points_snapshot.unix_timestamp", sinceDateTimeStamp)))
.SetFields("daily_points_snapshot", "facebook_id")
which I soon realised will not work for what I want.
Any help will be appreciated!
Thanks!
EDIT: My Solution to this
If anyone is looking to get a quick fix to this, this is what I ended up doing:
var points = MyDatabase[COLLECTION_NAME]
.Find(Query.EQ("facebook_id", XX))
.SetFields("points_snapshot", "facebook_id")
.FirstOrDefault();
if (points != null) {
var pointsArray = points.AsBsonDocument["points_snapshot"].AsBsonArray
.Where(x => x.AsBsonDocument["unix_timestamp"].AsInt32 > sinceDateTimeStamp)
.ToList();
return pointsArray;
}
Is it possible to write one query which by which I can get the user for id 1 along with the snapshots after a particular day. eg: 1312330300?
Not possible.
The problem here is that MongoDB queries return all matching Documents. Your Document contains an array of objects, but MongoDB does not treat these as "Documents".
Now, you can limit the fields that are returned, but in your case you actually want to limit the "portions of an array" that are returned.
This is a long-outstanding issue, the JIRA ticket is here. The ticket is dated about 18 months ago and it continues to get pushed back. So if this type of query is critical to your architecture, you may have to re-design the architecture.