I have a collection containing data:
{
"_id" : ObjectId("51dfb7abe4b02f15ee93a7c7"),
"date_created" : "2013-7-12 13:25:5",
"referrer_id" : 13,
"role_name" : "Physician",
"status_id" : "1",
}
I am sending the query:
cmd {
"mapreduce" : "doctor" ,
"map" : "function map(){emit(this._id,this);}" ,
"reduce" : "function reduce(key,values){return values;}" ,
"verbose" : true ,
"out" : { "merge" : "map_reduce"} ,
"query" : { "$where" : "this.demographics.first_name=='makdoctest'"}
}
I am getting error as:
"errmsg" : "exception: count failed in DBDirectClient: 10071 error on invocation of $where function:\nJS Error: TypeError: this.demographics has no properties nofile_a:0"
As Sammaye says in a comment:
It means that somewhere in one of your documents demographics is null or does not exist, you need to do a null check first, but more importantly why are you dong this in a $where?
I would go even further that that, and I wouldn't even use the Map/Reduce mechanism here. It slow, can't use indexes and can not run in parallel with others.
You would be much better off using the Aggregation Framework where you can do something like:
db.doctor.aggregate( [
{ $match: { "demographics.first_name" : 'makdoctest' } },
{ $group: …
You didn't specify the final goal here, but once you do I can update the answer.
Related
I have a MongoDB collection like this:
{
"_id" : {
"processUuid" : "653d0937-2afc-4915-ad42-d2b69f344402",
"partnerId" : "p377"
},
"isComplete" : true,
"tasks" : {
"dbb361a7-4b73-4691-bde5-2b160346464f" : {
"sku" : "4060079000048",
"status" : "FAILED",
"errorList" : [....]
},
"790dbc6f-563d-4eb7-931c-3cc604563dc1" : {
"sku" : "4060079000130",
"status" : "SUCCESSFUL",
"errorList" : [....]
},
... more tasks
}
... more processes
}
I want to query a certain sku and couldnt find a way. I know i could write an aggregation pipeline to project the inner part of a task, but then i would lose the task identifier which i need in order to add some stuff to a task.
I know the document structure is weird, i would have done it different, but its given.
I tried what i found about querying nested documents and so on, but unfortunately didnt get it. Any hints are appreciated.
> db.movmodels.findOne()
{
"_id" : ObjectId("55320b0e0e9e0d9d0540593c"),
"username" : "punk",
"favMovies" : [
{
"alternate_ids" : {
"imdb" : "0137523"
},
"abridged_cast" : [
{
"characters" : [
"Tyler"
],
"id" : "162652627",
"name" : "Brad Pitt"
},
{
"characters" : [
"Narrator"
],
"id" : "162660884",
"name" : "Edward Norton"
},
{
"characters" : [
"Robert"
],
"id" : "162676383",
"name" : "Meat Loaf"
},
{
"characters" : [
"Angel Face"
],
"id" : "162653925",
"name" : "Jared Leto"
},
{
"characters" : [
"Boss"
],
"id" : "770706064",
"name" : "Zach Grenier"
}
],
"synopsis" : "",
"ratings" : {
"audience_score" : 96,
"audience_rating" : "Upright",
"critics_score" : 80,
"critics_rating" : "Certified Fresh"
},
"release_dates" : {
"dvd" : "2000-06-06",
"theater" : "1999-10-15"
},
"critics_consensus" : "",
"runtime" : 139,
"mpaa_rating" : "R",
"year" : 1999,
"title" : "Fight Club",
**"id" : "13153"**
}
],
"__v" : 0
}
This is my data in mongodb.
As I am new to mongodb I wanted to know query to get movie with a particular id.
The query that I tried is. I need to get the movie based on id so that I can remove it from my database
db.movmodels.findOne({username:"punk"},{favMovies:{id:13153}})
but this gives me error.
2015-04-18T05:41:26.221-0400 E QUERY Error: error: {
"$err" : "Can't canonicalize query: BadValue ported projection option: favMovies: { id: 13153.0 }",
"code" : 17287
}
at Error (<anonymous>)
at DBQuery.next (src/mongo/shell/query.js:259:15)
at DBCollection.findOne (src/mongo/shell/collection.js:188:22)
at (shell):1:14 at src/mongo/shell/query.js:259
There are several problems with your query:
The second parameter to find() is a projection, not part of the query. What you want is to supply one document for the query that has two properties: {"username" : "punk", favMovies : { ... } }
However, you also don't want to compare the entire sub-document favMovies, but you only want to match on one of its properties, the id, which requires to 'reach into the object' using the dot operator: {username:"punk", "favMovies.id" : 13153}.
However, that will probably not work yet, because 13153 is not the same as "13153", the latter being a string while the former is a number in JSON.
db.movmodels.findOne({username:"punk", "favMovies.id" : "13153"})
Keep in mind, however, that this will find the entire document for the user named "punk". I'm not sure what exactly your data structure should look like, but it appears you'll have to $pull the movie from the user. In general, I'd say you're embedding too much data into the user, but that's hard to tell without knowing the exact use case.
Here you go:
If you just wanted to get first user who has this fav movie:
db.movmodels.findOne({"favMovies.id": 13153});
And, if you want to know if that user has that movie as favorite.
db.movmodels.findOne({"favMovies.id": 13153, username:"punk"});
Second argument in the findOne is used to only return particular field.
You can use also $elemMatch projection operator (not to be confused with the $elemMatch query operator)
db.movmodels.find({username:"punk"},{favMovies:{$elemMatch:{id:"13153"}}});
`
If you want to find a movie that has another movie (with id 13153) in 'favMovies' array, then write the query as below:
db.movmodels.findOne({username:"punk",'favMovies.id':13153})
And if you want to find a movie with _id 55320b0e0e9e0d9d0540593cwrite the following query:
db.movmodels.findOne({username:"punk",'_id':ObjectId("55320b0e0e9e0d9d0540593c")})
My MongoDB collection is made up of 2 main collections :
1) Maps
{
"_id" : ObjectId("542489232436657966204394"),
"fileName" : "importFile1.json",
"territories" : [
{
"$ref" : "territories",
"$id" : ObjectId("5424892224366579662042e9")
},
{
"$ref" : "territories",
"$id" : ObjectId("5424892224366579662042ea")
}
]
},
{
"_id" : ObjectId("542489262436657966204398"),
"fileName" : "importFile2.json",
"territories" : [
{
"$ref" : "territories",
"$id" : ObjectId("542489232436657966204395")
}
],
"uploadDate" : ISODate("2012-08-22T09:06:40.000Z")
}
2) Territories, which are referenced in "Map" objects :
{
"_id" : ObjectId("5424892224366579662042e9"),
"name" : "Afghanistan",
"area" : 653958
},
{
"_id" : ObjectId("5424892224366579662042ea"),
"name" : "Angola",
"area" : 1252651
},
{
"_id" : ObjectId("542489232436657966204395"),
"name" : "Unknown",
"area" : 0
}
My objective is to list every map with their cumulative area and number of territories. I am trying the following query :
db.maps.aggregate(
{'$unwind':'$territories'},
{'$group':{
'_id':'$fileName',
'numberOf': {'$sum': '$territories.name'},
'locatedArea':{'$sum':'$territories.area'}
}
})
However the results show 0 for each of these values :
{
"result" : [
{
"_id" : "importFile2.json",
"numberOf" : 0,
"locatedArea" : 0
},
{
"_id" : "importFile1.json",
"numberOf" : 0,
"locatedArea" : 0
}
],
"ok" : 1
}
I probably did something wrong when trying to access to the member variables of Territory (name and area), but I couldn't find an example of such a case in the Mongo doc. area is stored as an integer, and name as a string.
I probably did something wrong when trying to access to the member variables of Territory (name and area), but I couldn't find an example
of such a case in the Mongo doc. area is stored as an integer, and
name as a string.
Yes indeed, the field "territories" has an array of database references and not the actual documents. DBRefs are objects that contain information with which we can locate the actual documents.
In the above example, you can clearly see this, fire the below mongo query:
db.maps.find({"_id":ObjectId("542489232436657966204394")}).forEach(function(do
c){print(doc.territories[0]);})
it will print the DBRef object rather than the document itself:
o/p: DBRef("territories", ObjectId("5424892224366579662042e9"))
so, '$sum': '$territories.name','$sum': '$territories.area' would show you '0' since there are no fields such as name or area.
So you need to resolve this reference to a document before doing something like $territories.name
To achieve what you want, you can make use of the map() function, since aggregation nor Map-reduce support sub queries, and you already have a self-contained map document, with references to its territories.
Steps to achieve:
a) get each map
b) resolve the `DBRef`.
c) calculate the total area, and the number of territories.
d) make and return the desired structure.
Mongo shell script:
db.maps.find().map(function(doc) {
var territory_refs = doc.territories.map(function(terr_ref) {
refName = terr_ref.$ref;
return terr_ref.$id;
});
var areaSum = 0;
db.refName.find({
"_id" : {
$in : territory_refs
}
}).forEach(function(i) {
areaSum += i.area;
});
return {
"id" : doc.fileName,
"noOfTerritories" : territory_refs.length,
"areaSum" : areaSum
};
})
o/p:
[
{
"id" : "importFile1.json",
"noOfTerritories" : 2,
"areaSum" : 1906609
},
{
"id" : "importFile2.json",
"noOfTerritories" : 1,
"areaSum" : 0
}
]
Map-Reduce functions should not be and cannot be used to resolve DBRefs in the server side.
See what the documentation has to say:
The map function should not access the database for any reason.
The map function should be pure, or have no impact outside of the
function (i.e. side effects.)
The reduce function should not access the database, even to perform
read operations. The reduce function should not affect the outside
system.
Moreover, a reduce function even if used(which can never work anyway) will never be called for your problem, since a group w.r.t "fileName" or "ObjectId" would always have only one document, in your dataset.
MongoDB will not call the reduce function for a key that has only a
single value
I am trying to filter mongo data by using the below query in mongodb version 2.6.1 but getting error.
MongoDB version 2.4.6 (Working):
> db.BC_1839.find({data: {$elemMatch:{$where : "this.First_name.toLowerCase().indexOf('kim') ==0"}}});
output:
{
"_id" : ObjectId("53719a9d5b9e5c8c110001b9"),
"data" : [
{
"First_name" : "Kimberely",
"Last_name" : "Weyman",
"Company_name" : "Scientific Agrcltl Svc Inc",
"Address" : "7721 Harrison St",
"City" : "Kingsway West",
"State" : "NS",
"Post" : "2208",
"Phone1" : "02-7091-8948",
"Phone2" : "0441-151-810",
"Email" : "kweyman#weyman.com.au",
"Web" : "http://www.scientificagrcltlsvcinc.com.au",
"active" : "true"
}
],
"history" : [
{
"timestamp" : "2014-05-13 06:07:55",
"event": "creation",
"createdby" : "Srikesh Infotech",
"creation_data" : [
{
"crm_base_contact_id" : "1839",
"crm_imported_files_id" : "1464"
}
]
},
{
"timestamp" : "2014-05-13 06:09:05",
"event" : "Task",
"createdby" : "Srikesh Infotech",
"Task_data" : [
{
"Campaign ID" : "193",
"Campagin Name" : "Test Campa1"
}
]
}
],
"ref" : [
{ "crm_base_contact_id" : "1839", "crm_imported_files_id" : "1464" }
]
}
MongoDB version 2.6.1(Not Working):
> db.BC_1839.find({data: {$elemMatch:{$where : "this.First_name.toLowerCase().indexOf('kim') ==0"}}});
output:
error: {
"$err" : "Can't canonicalize query: BadValue $elemMatch cannot contain $
where expression",
"code" : 17287
}
Same query executes in mongodb version 2.4.6 but not in mongodb version 2.6.1 Why???
It shouldn't have worked in earlier versions at all, as at the very least you have modified the scoping of this to now refer to "data" as a top level element. In short, this is no longer allowed and you really should not be using JavaScript methods unless you absolutely have to. Even then, there is probably still a better way in most cases.
But in fact this is an un-necessary use of JavaScript matching as it is not required when there are other operators existing that will do this.
You should be using a $regex form instead:
db.docs.find({ "data.First_name": /^kim/i })
Or anywhere within the field, remove the caret ^:
db.docs.find({ "data.First_name": /kim/i })
Which is pretty much as inefficient as JavaScript execution but not as much as there is not the overhead of processing through that interpreter engine. And of course it works everywhere.
Also think about what a query relying on JavaScript to resolve is actually doing:
Invokes a JavaScript interpreter instance
Converts BSON document types per document to JavaScript types
Evaluates JavaScript code in the interpreter per document
Casts JavaScript true|false back as a result per document
Considering that $regex ( but with a case insensitive match which is not optimal ) is doing the same operations but using the "pcre" C library natively without conversion and recasting per document, then it is clearly the sane choice of the two.
Please consider the following document, a part of the Runtime collection:
{
"entity_id" : 10,
"features" : [
{
"10" : "Test System 2"
},
{
"20" : "System 2 Description"
},
{
"180" : ISODate("2013-12-25T18:19:40.589Z")
},
{
"190" : ISODate("2013-12-25T18:19:40.589Z")
}
],
"_id" : ObjectId("52bb21bc8a2ebdc01c000001")
}
My goal is to update the value of the element of the "features" array having the key "20".
Here are the things I've tried (in mongo shell):
db.Runtime.findAndModify({ "query" : {"_id": "52bb21bc8a2ebdc01c000001"}, "update" : {$set : {"features.$.20":"Updated Description"}}} );
db.Runtime.findAndModify({ "query" : {"_id": "52bb21bc8a2ebdc01c000001"}, "update" : {$set : {"features['20']":"Updated Description"}}} );
db.Runtime.findAndModify({ "query" : {"_id": "52bb21bc8a2ebdc01c000001"}, "update" : {$set : {"features[1]":"Updated Description"}}} );
In all instances the shell prints
null
and nothing happens to the data. So, the main question is, of course, what is wrong with my code snippets. Also, how that "null" is supposed to get interpreted? And is there such a thing as mongo shell's log where one could find any clues? Many thanks for your help!
When using the $ positional operator in an update, your query needs to include a term that matches the element of the array you're updating:
db.Runtime.findAndModify({
query: {_id: ObjectId("52bb21bc8a2ebdc01c000001"),
'features.20': {$exists: true}},
update: {$set: {"features.$.20":"Updated Description"}}
})
Note that you also need to call ObjectId on your _id string to turn it into an actual ObjectId or it won't match the doc.