I'm using Mongodb to analysee a Nobel prizes dataset which documents look like these:
> db.laureate.find().pretty().limit(1)
{
"_id" : ObjectId("604bc8c847d640142f02b3b1"),
"id" : "1",
"firstname" : "Wilhelm Conrad",
"surname" : "Röntgen",
"born" : "1845-03-27",
"died" : "1923-02-10",
"bornCountry" : "Prussia (now Germany)",
"bornCountryCode" : "DE",
"bornCity" : "Lennep (now Remscheid)",
"diedCountry" : "Germany",
"diedCountryCode" : "DE",
"diedCity" : "Munich",
"gender" : "male",
"prizes" : [
{
"year" : "1901",
"category" : "physics",
"share" : "1",
"motivation" : "\"in recognition of the extraordinary services he has rendered by the discovery of the remarkable rays subsequently named after him\"",
"affiliations" : [
{
"name" : "Munich University",
"city" : "Munich",
"country" : "Germany"
}
]
}
]
}
As you see the column "prizes" has embedded documents and the query I am trying to do is finding only those laureates who won two prizes (which I already know to be Marie Curie and Linus Pauling) can you help me with that?
Thanks in advance!
The $size operator should work fine for this. You could read about it if you want in this link: https://docs.mongodb.com/manual/reference/operator/query/size/
Your new query:
db.laureate.find({prizes: {$size: 2}}).pretty().limit(1)
Related
I need help with following thing in MongoDB, what I'm trying to do is to get only marks in reviews into it's own array of values only.
Code i got so far:
db.lodging.aggregate([
{$project:{
reviews:"$host.reviews",host:"$host"
}
},
{$unwind: "$reviews"},
])
JSON Example:
"host" : {
"name" : "Grimes",
"surname" : "Terrell",
"gender" : "male",
"age" : NumberInt(55),
"picture" : "https://api.adorable.io/avatars/285/GrimesTerrell.png",
"reviews" : [
{
"reviewer" : "Mae Ryan",
"date" : "2015-06-01T02:41:46 -02:00",
"helpful" : NumberInt(8),
"kind" : NumberInt(1),
"responsive" : NumberInt(5)
},
{
"reviewer" : "Nixon Johnson",
"date" : "2016-02-08T10:35:12 -01:00",
"helpful" : NumberInt(1),
"kind" : NumberInt(1),
"responsive" : NumberInt(9)
},
]
}
This is what im trying to achieve:
{
"host" : {
"name" : "Grimes",
"surname" : "Terrell",
"gender" : "male",
"age" : NumberInt(55),
"picture" : "https://api.adorable.io/avatars/285/GrimesTerrell.png",
"reviews" : [
{
"marks" : [8,1,5],
},
{
"marks" : [1,1,9],
},
]
}
Assuming your marks' field names are always helpful, kind, responsive, you can use $map.
Here is a mongo playground for you reference
I'm trying to Order in ascending order the requirements that are not between 25,000 and 30,000. The requirements are information of an array which is inside of a document and the condition is that they can't be in that determined range. I'm trying to do it properly but i can't find any information about this.
Document structure
{
"_id" : ObjectId("5ec73abebd7e4d618a05734e"),
"code" : "A47",
"title" : "Software engineer",
"description" : "Analyze, design, create, test computer and software systems.",
"city" : "Madrid",
"date" : ISODate("2020-05-22T02:36:46.271Z"),
"salary" : 30000.0,
"active" : true,
"requirements" : [
"python",
"java",
"html5",
"C++",
"C#"
],
"info_company" : {
"cif" : "A00000000",
"name" : "FUTURE S.A",
"location" : "Madrid",
"web" : "www.future.es",
"about" : "We are a leading company in new technologies."
},
"pyme" : true
}
db.offers.update(
{ $ne : [ salary: {
$gte : 25000,
$lte : 35000 ]
} },
{
$push : {
requirements: {
$each : [] ,
$sort : 1
}
}
}
,
{
multi : true
} )
Lets say here is the same document:
{
"_id" : 1.0,
"custname" : "metlife",
"address" : {
"city" : "Bangalore",
"country" : "INDIA"
}
}
And if I want to push an extra field to this document, something like below:
db.customers.updateMany(
{"address.country":"INDIA"},
{$push : {city: "$address.country"}}
)
It results in wrong update:
{
"_id" : 1.0,
"custname" : "metlife",
"address" : {
"city" : "Bangalore",
"country" : "INDIA"
},
"city" : "$address.city"
}
Instead of this:
{
"_id" : 1.0,
"custname" : "metlife",
"address" : {
"city" : "Bangalore",
"country" : "INDIA"
},
"city" : "Bangalore"
}
How do I achieve the above result?
You can't refer to other field values in update currently (more here). There is a workaround in aggregation framework (using $out) but it will replace entire collection.
I think that you can consider using $rename in your case. It will not add new field but it can move city to the top level of your document.
db.customers.updateMany({"address.country":"INDIA"}, {$rename: {"address.city": "city"}})
will give you following structure:
{ "_id" : 1, "custname" : "metlife", "address" : { "country" : "INDIA" }, "city" : "Bangalore" }
like #mickl said : You can't refer to other field values in update currently,
you have to iterate through your collection to update the documents, try this :
db.eval(function() {
db.collection.find({"address.country":"INDIA"}).forEach(function(e) {
e.city= e.address.city;
db.collection.save(e);
});
});
Keep in mind that this will block the DB until all updates are done.
try this
db.customers.updateMany(
{"address.country":"INDIA"},
{$push : {city: "address.country"}}
)
remove $ sign
"-Kj9Penv_LMRUIPSet0b" : {
"categories" : [ "food", "fashion"],
"contact" : "profile/contact/eieiiieie888x7ww28288_x22",
"location" : "New York, United States",
"name" : "Billybob Smith",
"social" : {
"twitter" : {
"followers" : "1,002",
"nickname" : "#billybob"
}
},
"state" : "0"
},
"eieiiieie888x7ww28288_x22" : {
"categories" : [ "food", "fashion" ],
"contact" : "profile/contact/eieiiieie888x7ww28288_x22",
"location" : "New York, United States",
"name" : "Billybob Smith.",
"social" : {
"twitter" : {
"followers" : "1,002",
"nickname" : "#billybob"
}
},
"socialID" : "twitter_id|558969977",
"state" : "0",
"uniqueID" : "eieiiieie888x7ww2828"
},
This is one .JSON example of a duplicate in my database. I have a lot of duplicates in my database. The only common piece of data I capture which uniquely identifies each user is their contact link. What is my best course of action to seek and remove duplicates from my database? I'm totally stuck. The second entry example is the more accurate and complete entry. Ideally, I could remove the first one and leave the second one behind.
Could really use some help here! Thank you so much!
{
"_id" : 654321,
"first_name" : "John",
"last_name" : "Doe",
"interested_by" : [ "electronics", "sports", "music" ],
"address" : {
"name" : "John Doe",
"company" : "Resultri",
"street" : "1015 Mapple Street",
"city" : "San Francisco",
"state" : "CA",
"zip_code" : 94105
}
}
How can i find the name of elements in array 'intersted_by' using command??
You can have the size of your result in the mongo shell using :
db.collection.count()
Replace collection by the name of your collection. You can also add a find condition like this :
db.collection.find().count()
Like that, you wan restrict your result with deffernts clauses before count the numbers of data corresponding
Edit : don't forget to do the command use databaseName
if you're not in your database, it does'nt work
You can count the amount of keys by doing:
var count = Object.keys(myObject).length;