I want to use spring data with mongodb and want to implement a one to many relationship using document reference.
db should look like this:
{
_id = 123451232
"countryName":"India",
"status":"true",
"meetings":[123451233, 123451234]
}
{
_id = 123451233
"countryName":"china",
"status":"true"
}
{
_id = 123451234
"countryName":"china",
"status":"true"
}
TO achieve this i used dbRef
country model
#Document(collection = "country")
public class Country {
#Id
#Field("country_id")
private String countryId;
#Field("country_name")
#Indexed
private String countryName;
#Field("status")
private boolean status = true;
#DBRef
private List<Country> meetings= new ArrayList<Country>();
// getters and setters
i got an error
HTTP Status 500 - Request processing failed; nested exception is org.springframework.data.mapping.model.MappingException: Cannot create a reference to an object with a NULL id.
Related
I'm using spring data mongo. I have a collection within a document that when I add an item to it I would like to assign a new automatically generated unique identifier to it e.g. (someGeneratedId)
#Document(collection = "questionnaire")
public class Questionnaire {
#Id
private String id;
#Field("answers")
private List<Answer> answers;
}
public class Answer {
private String someGeneratedId;
private String text;
}
I am aware I could use UUID.randomUUID() (wrapped in some kind of service) and set the value, I was just wondering if there was anything out of the box that can handle this? From here #Id seems to be specific to _id field in mongo:
The #Id annotation tells the mapper which property you want to use for
the MongoDB _id property
TIA
No there is no out of the box solution for generating ids for properties on embedded documents.
If you want to keep this away from your business-logic you could implement a BeforeConvertCallback which generates the id's for your embedded objects.
#Component
class BeforeConvertQuestionnaireCallback implements BeforeConvertCallback<Questionnaire> {
#Override
public Questionnaire onBeforeConvert(#NonNull Questionnaire entity, #NonNull String collection) {
for (var answer : entity.getAnswers()) {
if (answer.getId() == null) {
answer.setId(new ObjectId().toString());
}
}
return entity;
}
}
You could also implement this in a more generic manner:
Create a new annotation: #AutogeneratedId.
Then listen to all BeforeConvertCallback's of all entities and iterate through the properties with reflection. Each property annotated with the new annotation gets a unique id if null.
I'd like to find all Offer documents by Offer.ProductProperties.brand:
#Document(collection = "offers")
public class Offer {
#Id
private String id;
#NotNull
#DBRef
private ProductProperties properties;
ProductProperties:
#Document(collection = "product_properties")
public class ProductProperties {
#Id
private String id;
#NotNull
#NotEmpty
private String brand;
Service:
Flux<ProductProperties> all = productPropertiesRepository.findAllByBrand(brand);
List<String> productPropIds = all.toStream()
.map(ProductProperties::getId)
.collect(Collectors.toList());
Flux<Offer> byProperties = offerRepository.findAllByProperties_Id(productPropIds);
But unfortunately byProperties is empty. Why?
My repository:
public interface OfferRepository extends ReactiveMongoRepository<Offer, String> {
Flux<Offer> findAllByProperties_Id(List<String> productPropertiesIds);
}
How to find all Offers by ProductProperties.brand?
Thanks!
After reading some documentation found out that You cannot query with #DBRef. Hence the message
Invalid path reference properties.brand! Associations can only be
pointed to directly or via their id property
If you remove DBRef from the field, you should be able to query by findAllByProperties_BrandAndProperties_Capacity.
So the only ways is how you are doing. i.e. Fetch id's and query by id.
As I said in the comment, the reason it is not working is because return type of findAllByProperties_Id is a Flux. So unless u execute a terminal operation, you wont have any result. Try
byProperties.collectList().block()
I have a webapp that uses a database with a composite key. I need to create an API which will accept the parameters of the composite key wherein each paramenter can be null.
(for eg. If all the parameters of the composite key are set as null and query is done, then it should just return all rows in db)
I have used QueryByExampleExeccutor but it keeps throwing a null pointer exception.
Below is the model indicative of 1 row of the DB
public class Row
{
#EmbeddedId
private RowKey rowkey;
#Column
private String rowAttribute;
//getters and setters for rowkey and rowAttribute
}
Below is the model indicative of RowKey
public class RowKey
{
#Column(name = "rowBlock")
private String rowBlock;
#Column(name = "rowSection")
private String rowSection;
//getters and setters for above fields
}
I'm using QueryByExampleExecutor by extending my Repository(or DAO) with it as
public interface RowRepo extends CrudRepository<Row, RowKey>, QueryByExampleExecutor<Row> {
}
In my service layer I use the following statement to call repo methods to return a list of matched rows from DB
public List<Row> getRowRangeQuery(rowBlock,rowSection,rowAttribute)
{
Row row = new Row(new RowKey(rowBlock,rowSection),rowAttribute);
List<Row> Result = (List<Row>)getRowRepository().findAll(Example.of(row));
return Result;
}
I get an InvocationTargetException which when unrolled reveals a null pointer Exception at rowSection.
I have an entity ProjectCycle mapped to mongo DB collection ProjectCycle. I am trying to retrieve 2 fields, _id and Status. I am able to retrieve both like the following
#Document(collection="ProjectCycle")
public class ProjectCycle {
#Id
private String id;
#Field("Status")
private String status;
//getters and setters
}
Application.java
Query query = new Query();
query.fields().include("Status");
Criteria criteria = new Criteria();
criteria.and("_id").is("1000");
query.addCriteria(criteria);
Iterable<ProjectCycle> objectList = mongoOperations.find(query, ProjectCycle.class);
for(ProjectCycle obj : objectList) {
System.out.println("_id "+obj.getId());
System.out.println("status "+obj.getStatus());
}
Output
_id 1000
status Approved
But, the problem is when i use an Entity with field private DBObject basicDbObject; instead of private String status; i am getting value as null instead of Approved
I have tried like the following
public class ProjectCycle {
#Id
private String id;
private DBObject basicDbObject;
//getter & setter
}
What I am trying to achieve is that, the collection 'ProjectCycle' is very large and creating a POJO corresponding to it is quiet difficult. Also I am only reading data from mongoDB. So creating the entire POJO is time wasting and tedious.
How I can achieve mapping between any field/fields from mongo Collection to entity?.
Will it be possible to create a Map<String, BasicDBObject> objectMap; to fields returned from query? I am using Spring-data-mongodb for the same.
Version details
Spring 4.0.7.RELEASE
spring-data-mongodb 1.7.2.RELEASE
Try mapping your query like below.
Iterable<BasicDBObject> objectList = mongoOperations.find(query, BasicDBObject.class, collectionname);
for(BasicDBObject obj : objectList) {
System.out.println("_id "+obj.get("id"));
System.out.println("status "+obj.get("status"));
}
I'm currently fighting with the spring-data-elasticsearch API. I need it to work on an alias with several indexes pointing on it.
Each indexes have the same types stored, but are juste day to day storage (1rst index are monday's resulsts, second are tuesday's resulsts....).
Some of the ElasticsearchRepository methods don't work because of the alias. I currently managed to do a search (findOne() equivalent) but I am not able to update an entity.
I don't know how to achieve that, I looked to the documentation and samples.. but I'm stuck.
My repository
public interface EsUserRepository extends ElasticsearchRepository<User, String>
{
#Query("{\"bool\" : {\"must\" : {\"term\" : {\"id_str\" : \"?0\"}}}}")
User findByIdStr(String idStr);
}
My Entity
#Document(indexName = "osintlab", type = "users")
public class User
{
// Elasticsearch internal id
#Id
private String id;
// Just a test to get the real object index (_index field), in order to save it
#Field(index = FieldIndex.analyzed, type = FieldType.String)
private String indexName;
// Real id, saved under the "id_str" field
#Field(type = FieldType.String)
private String id_str;
#Field(type = FieldType.String)
private List<String> tag_user;
}
What I tested
final IndexQuery indexQuery = new IndexQuery();
indexQuery.setId(user.getId());
indexQuery.setObject(user);
esTemplate.index(indexQuery);
userRepository.index(user));
userRepository.save(user))