I have a document stored in MongoDB that looks something like this:
{ '_id' : 'XXX', 'myProps' : [ { '_id' : 'YYY', 'propA' : 'ValueA' }, { '_id' : 'ZZZ', 'propA' : 'ValueB' } ] }
I'm using Morphia to model this into Java objects. What I would like to do is query for elements within myProps that have a propA value of 'ValueA'. Is this possible? Is it possible to query for specific values within a subdocument? I've tried using queries like:
myProps.propA == 'ValueA'
...but, I still see all values of myProps being returned. Is there something I'm missing in my query? Or is it not possible to make such a query using Morphia/MongoDB?
UPDATE: My code thus far...
My entity and embedded classes:
#Entity
public class MyTestClass implements Serializable {
#Id
private ObjectId id;
#Embedded
private List<MyProps> myProps;
...
}
#Embedded
public class MyProps {
private String propA;
...
}
I have created the appropriate DAO class for it by extending BasicDAO. Here is my query:
Query<MyTestClass> q = this.myTestClassDAO.createQuery();
q.field("myProps.propA").qual("ValueA");
MyTestClass result = q.get();
The code executes correctly, but when I look at result.getMyProps() I see a list containing ALL of the myProps values, not just the ones with propA == 'ValueA'.
Using the fluent interface it should be something like field("myProps.propA").equal("ValueA").field("myProps.propA").notEqual("ValueB").
Related
I am using jdk 1.8 , hibernate and jpa in my project. And using specification/criteria to build my search query.
I have a class A ( an hibernate entity) which has class B as an attribute. So, roughly, it looks like :
#Entity
class A {
Long id;
String comment;
#OneToOne
B b;
}
and...
#Entity
class B {
Long id;
String type;
}
My repository class looks like (roughly):
public interface ARepository extends PagingAndSortingRepository<A, Integer>,
JpaSpecificationExecutor<A> {
}
Most of the simple JPA queries are working as expected. Even the specification/criteria based directly on Class A is working. However, I need to create a dynamic query and that should be executed under "findAll" method of PagingAndSortingRepository class. This query should be equivalent to
select * from A a left join B b on a.b_id = b.id
where b.type='final' and a.comment='blah';
I created a similar logic as above in a specification like :
public Specification<A> getSpecification() {
return (itemRoot, query, criteriaBuilder) -> {
.........
List<Predicate> partialQueries = new ArrayList<>();
partialQueries.add(criteriaBuilder.equal(itemRoot.get("b.type"), "final"));
partialQueries.add(criteriaBuilder.equal(itemRoot.get("comment"), "blah"));
//Other queries to be added...
return criteriaBuilder.and(partialQueries.toArray(new Predicate[0]));
};
}
And getting error :
Unable to locate Attribute with the the given name [b.type] on this ManagedType [com.something.domain.A]
Any insight on how to create criteria/specification on a field that belongs to a nested object?
If you want to filter nested object. You can write
itemRoot.get("NestedTableName").get("nestedfieldname")
In your case - itemRoot.get("B").get("type")
itemRoot.get("Name of the nested object field in the root class").get("nestedfieldname");
Example:
cb.equal(root.get("b").get("type"),value)
In your case - itemRoot.get("b").get("type");
I have following MongoDB document:
#Data
#EqualsAndHashCode(callSuper = true)
#NoArgsConstructor
#AllArgsConstructor
#Accessors(chain = true)
#SuperBuilder
#Document(collection = ReasonDocument.COLLECTION)
public class ReasonDocument extends BaseDocument<ObjectId> {
public static final String COLLECTION = "reasons";
#Id
private ObjectId id;
#Indexed
private ObjectId ownerId;
#Indexed
private LocalDate date;
private Type type;
private String reason;
}
I would like to get all rows for ownerId with latest date and additionally filter some of them out. I wrote custom repository for that, where I use aggregation with a group statement:
public class ReasonsRepositoryImpl implements ReasonsRepository {
private final MongoTemplate mongoTemplate;
#Autowired
public ReasonsRepositoryImpl(MongoTemplate mongoTemplate) {
this.mongoTemplate = mongoTemplate;
}
public List<ReasonDocument> findReasons(LocalDate date) {
final Aggregation aggregation = Aggregation.newAggregation(
sort(Direction.DESC, "date"),
group("ownerId")
.first("id").as("id")
.first("reason").as("reason")
.first("type").as("type")
.first("date").as("date")
.first("ownerId").as("ownerId"),
match(Criteria.where("date").lte(date).and("type").is(Type.TYPE_A))
);
return mongoTemplate.aggregate(aggregation, "reasons", ReasonDocument.class).getMappedResults();
}
}
It is smart query but unfortunately it returns corrupted rows while testing:
java.lang.AssertionError:
Expecting:
<[ReasonDocument(id=5dd5500960483c1b2d974eed, ownerId=5dd5500960483c1b2d974eed, date=2019-05-14, type=TYPA_A, reason=14),
ReasonDocument(id=5dd5500960483c1b2d974ee8, ownerId=5dd5500960483c1b2d974ee8, date=2019-05-15, type=TYPA_A, reason=1)]>
to contain exactly in any order:
<[ReasonDocument(id=5dd5500960483c1b2d974eef, ownerId=5dd5500960483c1b2d974ee8, date=2019-05-15, type=TYPA_A, reason=1),
ReasonDocument(id=5dd5500960483c1b2d974efc, ownerId=5dd5500960483c1b2d974eed, date=2019-05-14, type=TYPA_A, reason=14)]>
elements not found:
<[ReasonDocument(id=5dd5500960483c1b2d974eef, ownerId=5dd5500960483c1b2d974ee8, date=2019-05-15, type=TYPA_A, reason=1),
ReasonDocument(id=5dd5500960483c1b2d974efc, ownerId=5dd5500960483c1b2d974eed, date=2019-05-14, type=TYPA_A, reason=14)]>
and elements not expected:
<[ReasonDocument(id=5dd5500960483c1b2d974eed, ownerId=5dd5500960483c1b2d974eed, date=2019-05-14, type=TYPA_A, reason=14),
ReasonDocument(id=5dd5500960483c1b2d974ee8, ownerId=5dd5500960483c1b2d974ee8, date=2019-05-15, type=TYPA_A, reason=1)]>
The id returned is the same as ownerId.
Could anyone say what is wrong with the query?
Im not entirely sure whether or not this may be the problem. But did you check how mongo has saved the ID? because even if you're grouping by ownerID. IF mongo has saved the item under the _id header in your Json. Then you need to refer it as _id
Ex: If it looks like this
{
"_id" : "2893u4jrnjnwfwpfn",
"name" : "Jenkins"
}
then your groupBy should be groupBy(_id) and not what you've written.
This happens to be limitation of MongoDB and ORM, unless I'm not aware of something.
According to documentation https://docs.mongodb.com/manual/reference/operator/aggregation/group/, native mongo query looks like this:
{
$group:
{
_id: <expression>, // Group By Expression
<field1>: { <accumulator1> : <expression1> },
...
}
}
So grouping itself creates new _id - if I group by ownerId that value will end up in _id field.
One way of solving this is by using:
.first("_id").as("oldId")
and creating a new type with oldId as a field that can be later used to map back to original Document.
I am creating a new endpoint in springboot that will return simple stats on users generated from an aggregate query in a mongo database. However I get a PropertyReferenceException. I have read multiple stackoverflow questions about it, but didn't find one that solved this problem.
We have a mongo data scheme like this:
{
"_id" : ObjectId("5d795993288c3831c8dffe60"),
"user" : "000001",
"name" : "test",
"attributes" : {
"brand" : "Chrome",
"language" : "English" }
}
The database is filled with multiple users and we want using Springboot aggregate the stats of users per brand. There could be any number of attributes in the attributes object.
Here is the aggregation we are doing
Aggregation agg = newAggregation(
group("attributes.brand").count().as("number"),
project("number").and("type").previousOperation()
);
AggregationResults<Stats> groupResults
= mongoTemplate.aggregate(agg, Profile.class, Stats.class);
return groupResults.getMappedResults();
Which produces this mongo query which works:
> db.collection.aggregate([
{ "$group" : { "_id" : "$attributes.brand" , "number" : { "$sum" : 1}}} ,
{ "$project" : { "number" : 1 , "_id" : 0 , "type" : "$_id"}} ])
{ "number" : 4, "type" : "Chrome" }
{ "number" : 2, "type" : "Firefox" }
However when running a simple integration test we get this error:
org.springframework.data.mapping.PropertyReferenceException: No property brand found for type String! Traversed path: Profile.attributes.
From what I understand, it seems that since attributes is a Map<String, String> there might be a schematic problem. And in the mean time I can't modify the Profile object.
Is there something I am missing in the aggregation, or anything I could change in my Stats object?
For reference, here are the data models we're using, to work with JSON and jackson.
The Stats data model:
#Document
public class Stats {
#JsonProperty
private String type;
#JsonProperty
private int number;
public Stats() {}
/* ... */
}
The Profile data model:
#Document
public class Profiles {
#NotNull
#JsonProperty
private String user;
#NotNull
#JsonProperty
private String name;
#JsonProperty
private Map<String, String> attributes = new HashMap<>();
public Stats() {}
/* ... */
}
I found a solution, which was a combination of two problems:
The PropertyReferenceException was indeed caused because attributes is a Map<String, String> which means there is no schemes for Mongo.
The error message No property brand found for type String! Traversed path: Profile.attributes. means that the Map object doesn't have a brand property in it.
In order to fix that without touching my orginal Profile class, I had to create a new custom class which would map the attributes to an attributes object having the properties I want to aggreate on like:
public class StatsAttributes {
#JsonProperty
private String brand;
#JsonProperty
private String language;
public StatsAttributes() {}
/* ... */
}
Then I created a custom StatsProfile which would leverage my StatsAttributes and would be similar to the the original Profile object without modifying it.
#Document
public class StatsProfile {
#JsonProperty
private String user;
#JsonProperty
private StatsAttributes attributes;
public StatsProfile() {}
/* ... */
}
With that I made disapear my problem with the PropertyReferenceException using my new class StatsAggregation in the aggregation:
AggregationResults<Stats> groupResults
= mongoTemplate.aggregate(agg, StatsProfile.class, Stats.class);
However I would not get any results. It seems the query would not find any document in the database. That's where I realied that production mongo objects had the field "_class: com.company.dao.model.Profile" which was tied to the Profile object.
After some research, for the new StatsProfile to work it would need to be a #TypeAlias("Profile"). After looking around, I found that I also needed to precise a collection name which would lead to:
#Document(collection = "profile")
#TypeAlias("Profile")
public class StatsProfile {
/* ... */
}
And with all that, finally it worked!
I suppose that's not the prettiest solution, I wish I would not need to create a new Profile object and just consider the attributes as a StatsAttributes.class somehow in the mongoTemplate query. If anyone knows how to, please share 🙏
I'm trying to fetch all the entries in my database, but only the reference fields. In my MongoRepository, I want to use a custom query, so it doesn't use the method name to build up the query. The following doesn't seem to work:
public interface JvRepository extends MongoRepository<Jv, String> {
#Query(value = "{}", fields = "{ id : 0, reference : 1 }")
public List<String> findAllJvReferences();
}
public class Jv {
#Id
private String id;
private String reference;
}
The error is:
Jv cannot be cast to java.lang.String
I tell it to not get the id, and do get the reference right? Why does it not return a String, but still a Jv?
I guess I should pass something in the value that tells Mongo to select everything, but I have no idea what. Or is there something else wrong with this code?
I am using morphia 0.109 and have defined a base class as follows:
#Entity
public abstract class MorphiaData {
#Id protected ObjectId objectId;
#Version private Long mongodocversion;
}
And the intended Morphia entity
public class ItemTest extends MorphiaData {
public Long testValue;
}
When I save an instance of ItemTest to mongoDB the document looks as follows:
{
"_id" : ObjectId("54d26ed66aca89c0717e8936"),
"className" : "test.ItemTest",
"testValue" : NumberLong(1423077078)
}
I am expecting to see a value of mongodocversion in the document.
The morphia documentation provides the following information regarding the version annotation:
This field will be automatically managed for you -- there is no need
to set a value and you should not do so anyway.
#Entity
class MyClass {
...
#Version Long v;
}
which I believe I am adhering too. I have attempted the following fixes without success:
Moving the version annotation in the child class.
Removing the 'private' declaration of the version parameter.
Any advice would be greatly appreciated.
Edit to add: The save process I am using:
DBObject document = MongoDbFactory.getMorphia().toDBObject(this);
DB db = MongoDbFactory.getClient();
DBCollection coll = db.getCollection(noSqlCollection.toString());
if (this.objectId != null) {
//This is an update
BasicDBObject searchQuery = new BasicDBObject().append("_id", this.objectId);
coll.update(searchQuery, document);
} else {
//This is just an add
coll.insert(document);
this.objectId = (ObjectId)document.get( "_id" );
}
This test currently is passing on jenkins: https://github.com/mongodb/morphia/blob/master/morphia/src/test/java/org/mongodb/morphia/optimisticlocks/VersionTest.java#L20-20