MongoDB aggregation $unwind equivalent of ElasticSearch - mongodb

I'm pretty new to ElasticSearch, I recently indexed one of my MongoDB collection on ElasticSearch using compose transporter. The reason I indexed is I wanted to do full-text search on some of the fields.
So, now I have a nested document like below,
{
"item":"journal",
"item_size":200,
"instock":[
{
"warehouse":"A",
"qty":5
},
{
"warehouse":"A",
"qty":15
}
]
}
If I want to do a MongoDB aggregate on the doc to match where warehouse is A and $unwind them,
[{"$unwind":"$instock"},{"$match":{"instock.warehouse":"A"}}]
I'll get the following result,
{
"item":"journal",
"item_size":200,
"instock":
{
"warehouse":"A",
"qty":5
}
}
{
"item":"journal",
"item_size":200,
"instock":
{
"warehouse":"A",
"qty":15
}
}
This is just a simple example but I have more nested complex documents like this in MongoDB. How can I achieve the same result in the ElasticSearch?
I spent a lot of time figuring out this but no luck.

Related

MongoDB query over several collections with one sort stage

I have some data with identical layout divided over several collections, say we have collections named Jobs.Current, Jobs.Finished, Jobs.ByJames.
I have implemented a complex query using some aggregation stages on one of these collections, where the last stage is the sorting. It's something like this (but in real it's implemented in C# and additionally doing a projection):
db.ArchivedJobs.aggregate([ { $match: { Name: { $gte: "A" } } }, { $addFields: { "UpdatedTime": { $max: "$Transitions.TimeStamp" } } }, { $sort: { "__tmp": 1 } } ])
My new requirement is to include all these collections into my query. I could do it by simply running the same query on all collections in sequence - but then I still need to sort the results together. As this sort isn't so trivial (using an additional field being created by a $max on a sub-array) and I'm using skip and limit options I hope it's possible to do it in a way like:
Doing the query I already implemented on all relevant collections by defining appropriate aggregation steps
Sorting the whole result afterwards inside the same aggregation request
I found something with a $lookup stage, but couldn't apply it to my request as it needs to do some field-oriented matching (?). I need to access the complete objects.
The data is something like
{
"_id":"4242",
"name":"Stream recording Test - BBC 60 secs switch",
"transitions":[
{
"_id":"123",
"timeStamp":"2020-02-13T14:59:40.449Z",
"currentProcState":"Waiting"
},
{
"_id":"124",
"timeStamp":"2020-02-13T14:59:40.55Z",
"currentProcState":"Running"
},
{
"_id":"125",
"timeStamp":"2020-02-13T15:00:23.216Z",
"currentProcState":"Error"
} ],
"currentState":"Error"
}

Mongo db - Querying documents using nested field (nested array and objects)

{
"_id":"12345",
"model":{
"T":0,
"serviceTask":[
{
"_id":"6789",
"obj":{
"params" :{
"action": "getEmployeeData",
"employeeId":"123"
},
"url":"www.test.com",
"var":"test",
},
"opp":100
}
]
}
}
I have similar structured documents in my collection. How do I query the documents that match action value to "getEmployeeData". I tried dot notation with $elemMatchbut couldn't get the results.
Dot notation works fine here, it will return the document if serviceTask contains at least one action set to getEmployeeData
db.collection.find({
"model.serviceTask.obj.params.action": "getEmployeeData"
})

How to extract the creation date of _id and add it as a new field using the aggregation framework?

I have been trying for a while to extract the insertion date of a mongodb document and add it as a new field to the same document.
I'm trying to do it using the mongo and mongo shell aggregation framework without getting good results.
Here is my query
db.getCollection('my_collection').aggregate(
[
{
$match: {
MY QUERY CRITERIA
}
},
{
$addFields: { "insertTime": "$_id.getTimestamp()" }
}
]
)
I am trying to extracr insertion time from _id using the function getTimestamp() but for sure there is somtehing about aggregation framework syntax that I am missing because I can not do what I am trying to do in my query.
This works perfect:
ObjectId("5c34f746ccb26800019edd53").getTimestamp()
ISODate("2019-01-08T19:17:26Z")
But this does not work at all:
"$_id.getTimestamp()"
What I am missing?
Thanks in advance

mongodb how to project first child

I got a mongo db collection with structure
randomstring - means the string is actually random its diffrent in each document of the collection.
{
"notrandom":{
"randomstring":{
"randomstring":{
"randomstring":{
"notrandom2":"data"
}
}
}
}
}
how can i project this data out?
something like
db.mydb.aggregate( "notrandom[0][0].notrandom2":1}} , ] )
what i'm trying to achieve is a collection of all the notrandom2 values.
if you you to move notrandom2 to higer level in document structure,
you could use $project stage like this:
{
$project:{
_id:1,
notrandom2:"notrandom.randomstring.randomstring.randomstring.notrandom2",
// list all others fields with field:1 if you want them to appear down in pieline
}}
if this field is a part of an array then you need to $unwind first and then $project
You can use the following query
db.mydb.find({<findquery (in you have any)>},{"notrandom.randomstring.randomstring.randomstring.notrandom2" : 1}).
toArray(function(err, result)
{
console.log(result); //Array of objects with `notrandom2` values
})

How to translate this Mongodb clause into mongoengine clause?

db.students.find( { grades: { $elemMatch: {
mean: { $gt: 70 },
grade: { $gt:90 }
} } },
{ "grades.$": 1 } )
this is on official mongodb document, I have troubling translate them into mongoengine clause.
Can anybody translate this mongodb clause into mongoengine clause?
Because I have a embedded document in an array, I need to filter something inside the embedded document, I found this on the document, but don't know the exactly way to translate it. thank you!
I got the answer, but I do it another way around, I implement elasticsearch into my mongodb to be the search engine, so that's not the problem