Develop Reference

Spring Java Mongodb Aggregation check userId in array

I have a MongoDB database with users and questions.
My Question document:
{
"_id" : "b943d57a-f4c3-4394-86f7-dd1d1b5e2563",
"_class" : "org.company.app.model.Question",
"statement" : "First question for testing purposes",
"userMail" : "themail#mail.com",
"responses" : [
{
"responseId" : "6b60e900-0fec-47d2-8853-e1ea3508abe6",
"responseType" : "TEXT",
"mail" : "themail2#mail.com",
"responseTime" : ISODate("2017-11-22T11:23:10.848Z"),
"data" : "New Response 1",
"likes" : [
"themail3#mail.com",
"themail5#mail.com"
],
"dislikes" : [],
"state" : "PUBLISHED",
"stateTime" : ISODate("2017-11-22T11:23:10.848Z")
}
],
"categories" : [
"Category1",
"Category2",
"Category3"
],
"creationTimestamp" : ISODate("2017-10-26T14:50:12.717Z"),
"lastUpdateTimestamp" : ISODate("2017-11-02T15:35:20.818Z"),
"deleted" : false,
"active" : true,
"state" : "PUBLISHED"
}
and the user document:
{
"_id" : "1f4b5091-c755-4083-880e-e1c4696f7236",
"_class" : "org.company.app.model.User",
"allowsComms" : true,
"registrationConfirmed" : false,
"placeOfWork" : "Urban records",
"name" : "John",
"surname" : "Doe",
"mail" : "themail3#mail.com",
"phone" : "[ \"1111111111\" , \"2222222222222\"]",
"birthDate" : ISODate("1971-12-10T23:00:00.000Z"),
"gender" : "MALE",
"nationality" : "US",
"language" : "en",
"socialNetworks" : {
"INSTAGRAM" : "#instagram",
"TWITTER" : "#twitter"
},
"specialty" : "alternative rock",
"subspecialty" : "sub_3",
"creationTimestamp" : ISODate("2017-10-31T10:13:12.131Z"),
"lastUpdateTimestamp" : ISODate("2017-11-13T10:23:37.637Z"),
"deleted" : false,
"active" : true,
"profileImage" : "image"
}
From that point, I'm creating a new aggregation to join both collections, get user information and count likes and dislikes instead of return all the user ids at that array.
public List<JoinedResponse> getResponses(String userId, String questionId, long itemsPerPage, long requestedPage) {
Assert.hasLength(questionId, "questionId cannot be null or empty");
MatchOperation questionIdMatch = Aggregation.match(new Criteria("_id").is(questionId));
MatchOperation responsesStateMatch = Aggregation.match(Criteria.where("responses.state")
.in(QuestionState.PUBLISHED.toString(), QuestionState.APPROVED.toString()));
LookupOperation userInfoLookUpOperation = LookupOperation.newLookup().from("User").localField("$responses.mail").foreignField("mail")
.as("userInfo");
ProjectionOperation fieldsProjectionOperation = Aggregation.project(Fields.from(
Fields.field("responseId", "$responses.responseId"),
Fields.field("responseType", "$responses.responseType"),
Fields.field("mail", "$responses.mail"),
Fields.field("responseTime", "$responses.responseTime"),
Fields.field("data", "$responses.data"),
Fields.field("state", "$responses.state"),
Fields.field("userName", "$userInfo.name"),
Fields.field("userSurname", "$userInfo.surname"),
Fields.field("profileImage", "$userInfo.profileImage")))
.and("$responses.likes").size().as("likes")
.and("$responses.dislikes").size().as("dislikes");
// Creates the Aggregation: THE ORDER IS IMPORTANT!!!
Aggregation ag = Aggregation.newAggregation(
questionIdMatch,
Aggregation.unwind("responses"),
responsesStateMatch,
userInfoLookUpOperation,
Aggregation.unwind("userInfo"),
fieldsProjectionOperation,
Aggregation.project("responseId", "userName", "userSurname", "mail", "responseType", "responseTime",
"data", "likes", "dislikes", "profileImage", "state"/*, "isLiked"*/),
Aggregation.skip((long) ((requestedPage - 1) * itemsPerPage)),
Aggregation.limit(itemsPerPage));
logger.debug(ag.toString());
AggregationResults< JoinedResponse > output = mongoTemplate.aggregate(ag, "Question",
JoinedResponse);
Well, at this point, I need to know if the userId is in the liked or disliked list and I have spend a lot of hours investigating with no result. Of course, I would like to do it with aggregation.
Any help will be appreciated.
Thank you!

Spring Data MongoDB Aggregate with many fields in _id

I would like to make an aggregate with Spring Data MongoDB and I don't know how to make this group stage :
$group: {
_id: {
field1: "$field1",
field2: "2017-06-21",
field3: "$field3"
},
...
}
I don't know how to put the constant date into the second field of the _id
For the moment i do this :
groupOperation = group("field1","field3")
But i'm not sure that it make a group stage on the value of fields and i don't no how put a new field into _id.
I don't find good doc about the operation of different stage of an aggregate in Spring data MongoDB
If someone has an idea I'm interested
Thank you in advance

Fields fields = Fields.fields("field1", "field2", "field3");
GroupOperation groupOp = Aggregation.group(fields);
This will make group block
$group: {
_id: {
field1: "$field1",
field2: "$field2",
field3: "$field3"
}

Here is an example of using multiple fields on group and count the values.
Aggregation aggregate = Aggregation.newAggregation(Aggregation.group("category", "status").count().as("Categoury_Status_Count"));
AggregationResults<String> aggregateResult = mongoOperations.aggregate(aggregate, "category", String.class);
System.out.println(aggregateResult.getMappedResults());
My Sample Data:-
/* 1 */
{
"_id" : 1,
"category" : "cafe",
"status" : "A"
}
/* 2 */
{
"_id" : 2,
"category" : "cafe",
"status" : "B"
}
/* 3 */
{
"_id" : 3,
"category" : "cafe1",
"status" : "A"
}
/* 4 */
{
"_id" : 4,
"category" : "cafe1",
"status" : "B"
}
/* 5 */
{
"_id" : 5,
"category" : "cafe1",
"status" : "B"
}
Output:-
[{ "category" : "cafe1" , "status" : "A" , "Categoury_Status_Count" : 1}, { "category" : "cafe" , "status" : "B" , "Categoury_Status_Count" : 1}, { "category" : "cafe1" , "status" : "B" , "Categoury_Status_Count" : 2}, { "category" : "cafe" , "status" : "A" , "Categoury_Status_Count" : 1}]
To get the _id in the output:-
You can add the _id to the set.
Aggregation aggregate = Aggregation.newAggregation(Aggregation.group("category", "status").count().as("Categoury_Status_Count").addToSet("_id").as("ids"));
Output:-
[{ "category" : "cafe1" , "status" : "A" , "Categoury_Status_Count" : 1 , "ids" : [ 3.0]}, { "category" : "cafe" , "status" : "B" , "Categoury_Status_Count" : 1 , "ids" : [ 2.0]}, { "category" : "cafe1" , "status" : "B" , "Categoury_Status_Count" : 2 , "ids" : [ 5.0 , 4.0]}, { "category" : "cafe" , "status" : "A" , "Categoury_Status_Count" : 1 , "ids" : [ 1.0]}]

mongo Java search by array

I've been working with mongo for a few months and I'm struggling now.
Here is a document example of my database:
"_id" : ObjectId("5732d96fed40761e640a3f3e"),
"_familyId" : "12345",
"_applications" : [
{
"_applicationRID" : "123456",
"_applicationDate" : "01012000",
"_isRepresentative" : false,
"_applicationId" : {
"CC" : "AB",
"SN" : "123456789",
"KC" : "A"
},
"_publications" : [
{
"_publicationRID" : "123456789",
"_publicationDate" : "01012000",
"_flaId" : "AB123456789A",
"_publicationId" : {
"CC" : "AB",
"SN" : "1234567",
"KC" : "B"
},
[...]
Now, I'm trying to do a collection.find() in Java on an array.
I know all the fields contained in _publicationId and I need to search on _publicationId because it has an index but not the fields inside it.
In shell it would be:
db.collection.find({
"_applications._publications._publicationId": {
"CC": "AB",
"SN": "1234567",
"KC": "B"
}
})
and this works fine.
Using java, I can't find the proper syntax:
collection.find("_applications._publications._publicationId", ??? )

You should try with a query of the next type that is actually the exact equivalent of your query in java:
DBObject query = new BasicDBObject(
"_applications._publications._publicationId",
new BasicDBObject("CC", "AB").append("SN", "1234567").append("KC", "B")
);
DBCursor cursor = collection.find(query);

Java query for mongodb to find documents where list size is less than n

I'm trying to find all of the documents in my db where the the size of my "states" list only contains one state but I'm struggling with the syntax of the java code.
My db looks like this:
{ "_id" : 13218 , "country" : { "MY" : 11 , "US" : 4} , "state" : { "WA" : 4 }}
{ "_id" : 95529 , "country" : { "US" : 6 } , "state" : { "MI" : 6 }}
{ "_id" : 22897 , "country" : { "US" : 4 } , "state" : { "CA" : 2 , "TX" : 1 , "WY" : 1 }}
What I want to do is print out every "_id" found from the US that only has a single state. So, the only "_id" that'd be returned here is 95529.
here is the relevant portion of code:
DBObject query = new BasicDBObject("country.US", new BasicDBObject("$gt", 4));
//query.put("state.2", new BasicDBObject("$exists", true));
//This is my attempt at checking the list length but it doesn't work
DBCursor dbCursor = dBcollection.find(query);
while (dbCursor.hasNext()){
DBObject record = dbCursor.next();
Object _id= record.get("_id");
Object state= record.get("state");
System.out.println(_id + "," + state);
}
current output looks like this:
95529, { "MI" : 6 }
22897, { "CA" : 2 , "TX" : 1 , "WY" : 1 }

The essential problem you have here is that your data is not in fact a "list". As a "hash" or "map" which is what it really is there is no concept of "length" in a MongoDB sense.
You would be better off changing your data to use actual "arrays" which is what a list actually is:
{
"_id" : 13218 ,
"country" : [
{ "code": "MY", "value" : 11 },
{ "code": "US", "value" : 4 },
],
"state" : [{ "code": "WA", "value" : 4 }]
},
{
"_id" : 95529 ,
"country" : [{ "code": "US", "value" : 6 }],
"state" : [{ "code": "MI", "value" : 6 }]
},
{
"_id" : 22897 ,
"country" : [{ "code": "US", "value" : 4 }],
"state" : [
{ "code": "CA", "value" : 2 },
{ "code": "TX", "value" : 1 },
{ "code": "WY", "value" : 1 }
]
}
Then getting those documents that only have a single state is a simple matter of using the $size operator.
DObject query = new BasicDBObject("country",
new BasicDBObject( "$elemMatch", new BasicDBObject(
"code", "US").put( "value", new BasicDBObject( "$gt", 4 )
)
);
query.put( "state": new BasicDBObject( "$size", 1 ) );
This ultimately gives you a lot more flexibilty in issuing queries as you don't need to specify the explicit "key" in each query. Also as noted, there is a concept of length here that does not otherwise exist.
If you keep your data in it's current form then the only way to do this is with the JavaScript evaluation of the $where operator. That is not very efficient as the interpreted code needs to be run for each document in order to determine if the condition matches:
DBObject query = new BasicDBObject("country.US", new BasicDBObject("$gt", 4));
query.put("state", new BasicDBObject( "$type", 3 ));
query.put("$where","return Object.keys( this.state ).length === 1");
Also using the $type operator in order to make sure that "state" is actually present and an "Object" that is expected. So possible, but not a really great idea do to performance.
Try to change your document structure as it will make other sorts of queries possible without using JavaScript evaluation.

MongoDB Query in Array of Arrays and add if not present

I have
{
"Districts" :
[{ "name" : "Krishna"
, "Locations" : [{ "name" : "Vijayawada"}
,{ "name" : "Machilipatnam"}]}
, { "name" : "Guntur"
, "Locations" : [{ "name" : "Satenpalli"}]}
]
, "_id" : 1
, "name" : "Andhra Pradesh"
}
I am trying to create one more Location "Achampet" if District name is "Guntur" so the result should be this below. The result should be the same even if I try to add Achampet more than once.
{
"Districts" :
[{ "name" : "Krishna"
, "Locations" : [{ "name" : "Vijayawada"}
,{ "name" : "Machilipatnam"}]}
, { "name" : "Guntur"
, "Locations" : [{ "name" : "Satenpalli"}
,{ "name" : "Achampet"}]}
]
, "_id" : 1
, "name" : "Andhra Pradesh"
}
But my java code doesn't work
DBObject newLoc = new BasicDBObject("Districts", new BasicDBObject("name", distName).append("Locations", new BasicDBObject("name", locName)));
if (statesColl.findOne(newLoc) == null) {
DBObject updateLoc = new BasicDBObject("$push", newLoc);
statesColl.update(queryDist, updateLoc);
}
It is creating a new District everytime I try to add a location. How can I fix this?

This is how you can do it using the $ positional operator in Java:
...
DBObject selectQuery = new BasicDBObject("_id", 1); // Matches the document
selectQuery.append("Districts.name", distName); // Matches the element in the array where District name = Guntur
BasicDBObject updateFields = new BasicDBObject();
updateFields.put("Districts.$.Locations", new BasicDBObject("name":"Achampet"));
DBObject updateQuery = new BasicDBObject("$addToSet", updateFields);
statesColl.update(selectQuery, updateQuery);
...