In my Meteor application, on the server side, I need to get data from Mongo, analyse and update it in Mongo if neŃessary. In the database, I have an array of objects:
{ "0" : { "title" : "This is title", "description" : "This is description", "link" : "http://123435", "pubDate" : "16 Oct 2014 20:46:00 +0400" }, "1" : { }, "3" : { } etc
I'm try get data from Mongo: var savedNews = News.find().fetch(), there News is my collection. And I see in debugger array of this type:
0: "_id"="uuTOncmcIoIkfc",
1: "_id"="mcmroidewiuIpf"
etc
I understand this is _id's, but I need access to the fields of objects. In Mongo console I can see my real objects if I type db.news.find(); How I can get data in the form of array or object?
Thank you.
Fetch() return an array, those records you get can get probably expanded, if not, maybe you don't publish all of this data.
For example, you should be able to get to data like this:
temp = Collection.find({_id:"1"}).fetch();
temp[0].variable
Or simply
temp = Collection.find({_id:"1"}).fetch()[0].variable;
If you need just one record try using findOne, this return just one array, so no use of fetch() or [] is required
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.
I have a situation where records in Mongo DB are like :
{
"_id" : "xxxx",
"_class" : "xxxx",
"orgId" : xxx,
"targetKeyToOrgIdMap" : {
"46784_56139542ecaa34c13ba9e314" : 46784,
"47530_562f1bc5fc1c1831d38d1900" : 47530,
"700004280_56c18369fc1cde1e2a017afc" : 700004280
},
}
I have to find out the records where child nodes of targetKeyToOrgIdMap has a particular set of values. That means, I know what the value is going to be there in the record in "46784_56139542ecaa34c13ba9e314" : 46784 part. And the field name is variable, its combination of the value and some random string.
In above example, I have 46784, and I need to find all the records which have 46784 in that respective field.
Is there any way I can fire some regex or something like that or by using any other mean where I would get the records which has the value I need in the child nodes of the field targetKeyToOrgIdMap.
Thanks in advance
You could use MongoDB's $where like this:
db.myCollection.find( { $where: function() {
for (var key in obj.targetKeyToOrgIdMap) {
if (obj.targetKeyToOrgIdMap[key] == 46784){
return true;
}
}
}}).each { obj ->
println obj
}
But be aware that this will require a full table scan where the function is executed for each document. See documentation.
We are trying to represent this data in a web application.What will be the appropriate way to represent this data? We thought of using relational structure but data are hierarchical in nature.Is it better to use MongoDB in this scenario ?
As per comment mongo dynamic schemas is a perfect solution.
let assume that we have our document structured like this:
report {
_id...
documentBycode {
_id : "G8",
dataSource,
remarks,
fields : [{
indicator : "sucide",
baseline {
data,
year,
source
},
milestone[{
year : 2017,
value : 15
}, {}
]
...
...
fields : [{
name : "nfhs1996",
value : "n/a",
order : 1 /* this is not mandatory*/
}, {
name : "ndhs2011",
value : "n/a",
order : 2
}
]
]
}
}
then you can add/modify elements as needed inside [arrays] and always get report data by retrieving only one document from datastore.
What's also could be interesting you could have mulitple diffrent reports structures stored in same collection - so you can literally store full ViewModel data AS IS
Any comment welcome!
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 },
{ $set: { roomId: roomId._id }}
)
}
})
You could tidy this up with some error checking, and for updates on a large collection consider using the Bulk Update API (only available in MongoDB 2.6+).
It seems that i can go further than one subdocument if i want to add it dynamicaly, here is the code:
db.users.update({"pup.cmn.id":id}, {"$addToSet":{"pup.cmn":{"abus":email}}})
this give error:
OperationFailure: can't append to array using string field name: cmn
then, if i add positional element i get this:
db.users.update({"pup.cmn.id":id}, {"$addToSet":{"pup.$.cmn":{"abus":email}}})
"cmn" :
[
{
"fto" : ObjectId("5190e8a53a5f3a0c102af045")
"id" : "14.05.2013 12:29:53"
},
{
"abus" : "u...#example.com"
}
]
so as you can see, it will add it in the same level, and i dont want that, because the application will get errors.
It seems that Mongodb for the time of writing (2.4.x) have not this feature, there is a ticket:
https://jira.mongodb.org/browse/SERVER-831