if we have a Product and Supplier object, where Product has a supplier and a supplier has a Product, how can we indicate to the entities that this is not an infinite cycle when obtaining the JSON of a product? this would be something like how could we configure this in java with JPA by levels? so that it is
Tag: jpa
How do I cast JPA criteria Expression to long java type
This code has not compile error but at run time gets this error: Cannot cast from Expression to int I tried using String: This also gets error: ERROR: For input string: “org.hibernate.query.criteria.internal.path.SingularAttributePath@2ed2d35d”; nested exception is java.lang.NumberFormatException:…
A bean named ‘entityManagerFactory’ that could not be found
I’m pretty new to Hibernate/JPA. Running the application, I’m getting this error: The main class (I use @EnableJpaRepositories to let Spring find the repository in other package): My main entity class: A repository: A properties file: Maven dependencies: What should I do here? Answer I solved this…
Best way to save and update entity Parent and child using spring data jpa
I’m facing some behaviour about spring data jpa and I need to understand. consider this : Document Template Service First => I created the template And When I created a new document for instance with this data configuration I’m getting this error detached entity passed to persist. So to resolve…
Hibernate: How to distinguish two uni-directional relationship and one bi-directional relationship?
in this answer, the author said: Take an example of two entities mapped without declaring a owning side: From a OO point of view this mapping defines not one bi-directional relation, but two separate uni-directional relations. 1.My first question is: Why it is not a bi-directional relation? Docs Oracle: In a …
What is difference between transient state and removed state in JPA?
I have a question about entity states in JPA. I’ve read some article about entity states in jpa and my understanding about them is that: a transient object is a newly created object that hasn’t been associated with Persistence Context and does not represent a record in database. and when we remove an ob…
JPA Using Composite Fields To Store Multiple @Column On An @Entity
I have a user table and I am using Hibernate to read it into User instances. I want to collect a number of related columns under a composite object to pass it around. So, I want to do something like this: Now I want to read some of the columns in the same user table into the fields in my
org.springframework.orm.jpa.JpaSystemException: Don’t change the reference to a collection with delete-orphan enabled
i’m using spring data jpa. when i want to clone an entity with one to many relation, i set the purchaseOrder id =null, and each items id = null, but get the follw exception here is purchaseOrder entity and items entity can any one help with this? Answer No need to reassociate items and purchaseOrder , j…
select new (JPQL Constructor Expression) in jpa/hibernate causes “lazy” loading for each row
Recently I found no obvious behaviour when using ‘select new/constructor expression’ in jpa/hibernate. It uses kind of lazy loading for each entity in each row in result set what is not efficient. Test example First case we issue a query using select new technique: This issues one query to fetch o…
Spring, Jpa : One To Many Error when the list contains values
I want to return a Profile Object in JSON containing a list of login details associated with a social network. Everything works correctly when the “reseaux_sociaux” table is empty. For my status table I get my statuses in JSON format in my Profile object. However, when “reseaux_sociaux”…