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CrudRepository - Hibernate - Overwrite existing model with manual set id

I have a problem which I try to figure out since many hours now.
I must save a model with manual set id in the database using CrudRepository and Hibernate.
But the manual set of the id is ignored always.
Is it somehow possible, to force
CrudRepository.save(Model m)
to persist the given Model with UPDATE?
The queries always results in INSERT statements, without using the id.
The reason I must do this manually is, that the identifier is not the database ID - it is a ID generated outside as UUID which is unique over multiple databases with this model-entry. This model is shared as serialized objects via hazelcast-cluster.
Following an example:
The database already contains a Model-Entry with the id 1:
id identifier_field_with_unique_constraint a_changing_number
1 THIS_IS_THE_UNIQUE_STRING 10
Now I need to update it. I create a new Model version
Model m = new Model();
m.setIdentifierFieldWithUniqueConstraint(THIS_IS_THE_UNIQUE_STRING);
m.setAChangingNumberField(20);
saveMe(m);
void saveMe(Model m) {
Optional<Model> presentModalOpt = modelCrudRepo.findByIdentField(THIS_IS_THE_UNIQUE_STRING)
if(presentModalOpt.isPresent()) {
// The unique value in my identifier field exists in the database already
// so use that id for the new model, so it will be overwritten
m.setId(modalOpt.get().getId());
} else {
m.setId(null);
}
// This call will now do an INSERT, instead of UPDATE,
// even though the id is set in the model AND the id exists in the database!
modelCrudRepo.save(m);
// ConstraintViolationException for the unique identifier field.
// It would be a duplicate now, which is not allowed, because it uses INSERT instead of UPDATE
}
The id Field is tagged with #Id and #GeneratedValue annotation (for the case that the id is null and the id should be generated)
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
I even tried to changed this field only to an #Id field without #GeneratedValue and generate the ID always on my own. It had no effect, it always used INSERT statements, never UPDATE.
What am I doing wrong?
Is there another identifier for the CrudRepository that declares the model as an existing one, other than the id?
I'm happy for any help.

CrudRepository has only save method but it acts for both insert as well as update.
When you do save on entity with empty id it will do a save.
When you do save on entity with existing id it will do an update
that means that after you used findById for example and changed
something in your object, you can call save on this object and it
will actually do an update because after findById you get an object
with populated id that exist in your DB.
In your case you are fetching the records based on a field (unique) But records will update only when the model object has a existing primary key value
In your code there should be presentModalOpt instead of modalOpt
void saveMe(Model m) {
Optional<Model> presentModalOpt = modelCrudRepo.findByIdentField(THIS_IS_THE_UNIQUE_STRING)
if(presentModalOpt.isPresent()) { // should be presentModalOpt instead of modalOpt
} else {
m.setId(null);
}
modelCrudRepo.save(m);
}
See the default implementation -
/*
* (non-Javadoc)
* #see org.springframework.data.repository.CrudRepository#save(java.lang.Object)
*/
#Transactional
public <S extends T> S save(S entity) {
if (entityInformation.isNew(entity)) {
em.persist(entity);
return entity;
} else {
return em.merge(entity);
}
}

BeanPropertyRowMapper when mapping for field not available

I have a repository class that calls jdbcTemplate query() and uses BeanPropertyRowMapper(..)
#Override
public List<Model> query(final Model model) {
return this.jdbcTemplate.query(
this.QUERY.replace("${WHERE}", this.queryBuilder.build(model)),
new PostGrePropertyMapper(model)
.addProperty("test", new TestMapper().apply(model.getTest())),
new BeanPropertyRowMapper<>(Model.class));
}
Say I have this model (it has many fields but for demo shortened to 3):
public class Model {
private String test;
private String id;
private String reference;
}
and the query returns me two columns: test & id in the ResultSet.
Is there a way I can set the value of the reference field to that of id that is being returned from database? The id and reference should be set off the id field coming from DB.
Where can I set this value for reference without having to write a custom row mapper and setting each and every field with rs.getString(...) calls.
Is there a short technique for such scenario?

The shortest technique is to fix the query so that it matches the model:
SELECT test, id, id as reference FROM ...

Update entity if already exists or create using spring jpa

I am new to spring data jpa. I have a scenario where I have to create an entity if not exists or update based on non primary key name.Below is the code i wrote to create new entity,it is working fine,but if an already exists record ,its creating duplicate.How to write a method to update if exists ,i usually get list of records from client.
#Override
#Transactional
public String createNewEntity(List<Transaction> transaction) {
List<Transaction> transaction= transactionRespository.saveAll(transaction);
}

Add in your Transaction Entity on variable called name this for naming as unique:
#Entity
public class Transaction {
...
#Column(name="name", unique=true)
private String name;
...
}
Then you won't be able to add duplicate values for name column.

First, this is from google composite key means
A composite key is a combination of two or more columns in a table that can be used to uniquely identify each row in the table when the columns are combined uniqueness is guaranteed, but when it taken individually it does not guarantee uniqueness.
A composite key with an unique key is a waste.
if you want to update an entity by jpa, you need to have an key to classify if the entity exist already.
#Transactional
public <S extends T> S save(S entity) {
if(this.entityInformation.isNew(entity)) {
this.em.persist(entity);
return entity;
} else {
return this.em.merge(entity);
}
}
There are two ways to handle your problem.
If you can not get id from client on updating, it means that id has lost its original function. Then remove your the annotation #Id on your id field,set name with #Id. And do not set auto generate for it.
I think what you want is an #Column(unique = true,nullable = false) on your name field.
And that is the order to update something.
Transaction t = transactionRepository.findByName(name);
t.set.... //your update
transactionRepository.save(t);

Updating with Morphia Optimistic locking

Hi considering the following example:
Resource:
#PUT
#Path("{id}")
public Response update(#PathParam(value = "id") final String id, final Person person) {
final Person person = service.getPerson(id);
final EntityTag etag = new EntityTag(Integer.toString(person.hashCode()));
// If-Match is required
ResponseBuilder builder = request.evaluatePreconditions(etag);
if (builder != null) {
throw new DataHasChangedException("Person data has changed: " + id);
}
service.updatePerson(id, person.getName());
....
}
Service:
public void updatePerson(final String id, final String name) {
final Query<Person> findQuery = morphiaDataStore.createQuery(Person.class).filter("id ==", id);
UpdateOperations<Person> operation = morphiaDataStore.createUpdateOperations(Person.class).set("name", name);
morphiaDataStore.findAndModify(findQuery, operation );
}
Person:
#Entity("person")
public class Person {
#Id
private ObjectId id;
#Version
private Long version;
private String name;
...
}
I do check if the etag provided is the same of the person within the database. However this check is been done on the resource itself. I don't think that this is safe since the update happens after the check and another thread could have gone threw the check in the meantime. How can this be solved correctly? Any example or advise is appreciated.

Morphia already implements optimistic-locking via #Version annotation.
http://mongodb.github.io/morphia/1.3/guides/annotations/#version
#Version marks a field in an entity to control optimistic locking. If the versions change in the database while modifying an entity (including deletes) a ConcurrentModificationException will be thrown. This field will be automatically managed for you – there is no need to set a value and you should not do so. If another name beside the Java field name is desired, a name can be passed to this annotation to change the document’s field name.
I see you have already use the annotation in your example. Make sure the clients include the version of the document as part of the request so you can also pass it to morphia.
Not sure if findAndModify will be able to handle it (I would think it does). but at least I'm sure save does handle it.
Assuming the object person contains the new name and version that the client was looking at, you can do directly something like this to update the record:
morphiaDataStore.save(person);
If there was another save before this client could pick it up the versions will no longer match and a ConcurrentModificationException will be issued with this message:
Entity of class %s (id='%s',version='%d') was concurrently updated

hibernate auto_increment getter/setter

I have a class which is mapped to a table using the hibernate notations of auto increment. This class works fine when I set values and update this to the database and I get a correct updated value in the table.
But the issue is when I create a new object of this class and try to get the id, it returns me a 0 instead of the auto_incremented id.
The code of the class is
#Entity(name="babies")
public class Baby implements DBHelper{
private int babyID;
#Id
#Column(name="babyID", unique=true, nullable= false)
#GeneratedValue(strategy = GenerationType.AUTO)
public int getBabyID() {
return babyID;
}
public void setBabyID(int babyID) {
this.babyID = babyID;
}
}
The code I use to get the persistent value is
Baby baby = new Baby();
System.out.println("BABY ID = "+baby.getBabyID());
This returns me a
BABY ID = 0
Any pointers would be appreciated.
Thanks,
Sana.

Hibernate only generates the id after an entity becomes persistent, ie after you have saved it to the database. Before this the object is in the transient state. Here is an article about the Hibernate object states and lifecycle

The ID is set by hibernate when object is saved and became persistable.
The annotation are only informing hibernate, how he should behave with class, property, method that annotation refer to.
Another thing if You have current id value how hibernate, would be able to recognize that he should insert or only update that value.
So this is normal expected behavior.