What is the difference between: @Entity public class Company { @OneToMany(cascade = CascadeType.ALL , fetch = FetchType.LAZY) @JoinColumn(name = “companyIdRef”, referencedColumnName = “companyId”) private List<Branch> branches; … } and @Entity public class Company { @OneToMany(cascade = CascadeType.ALL , fetch = FetchType.LAZY, mappedBy = “companyIdRef”) private List<Branch> branches; … } 8 s 8 The annotation @JoinColumn … Read more
I am a newbie to Java Persistence API and Hibernate. What is the difference between FetchType.LAZY and FetchType.EAGER in Java Persistence API? 17 s 17 Sometimes you have two entities and there’s a relationship between them. For example, you might have an entity called University and another entity called Student and a University might have … Read more
Closed. This question is opinion-based. It is not currently accepting answers. Closed 4 years ago. Locked. This question and its answers are locked because the question is off-topic but has historical significance. It is not currently accepting new answers or interactions. I understand that JPA 2 is a specification and Hibernate is a tool for … Read more
I receive following error when I save the object using Hibernate object references an unsaved transient instance – save the transient instance before flushing 3Best Answer 31
What is the difference between CrudRepository and JpaRepository interfaces in Spring Data JPA? When I see the examples on the web, I see them there used kind of interchangeably. What is the difference between them? Why would you want to use one over the other? 7 s 7 JpaRepository extends PagingAndSortingRepository which in turn extends … Read more
EntityManager.merge() can insert new objects and update existing ones. Why would one want to use persist() (which can only create new objects)? 15 s 15 Either way will add an entity to a PersistenceContext, the difference is in what you do with the entity afterwards. Persist takes an entity instance, adds it to the context … Read more
Error creating bean with name ‘entityManagerFactory’ defined in class path resource : Invocation of init method failed
JpaRepository extends PagingAndSortingRepository which in turn extends CrudRepository. Their main functions are: Because of the inheritance mentioned above, JpaRepository will have all the functions of CrudRepository and PagingAndSortingRepository. So if you don’t need the repository to have the functions provided by JpaRepository and PagingAndSortingRepository , use CrudRepository.
The EntityManager doesn’t flush change automatically by default. You should use the following option with your statement of query: @Modifying(clearAutomatically = true) @Query(“update RssFeedEntry feedEntry set feedEntry.read =:isRead where feedEntry.id =:entryId”) void markEntryAsRead(@Param(“entryId”) Long rssFeedEntryId, @Param(“isRead”) boolean isRead);
First remove all of your configuration Spring Boot will start it for you. Make sure you have an application.properties in your classpath and add the following properties. spring.datasource.url=jdbc:postgresql://localhost:5432/teste?charSet=LATIN1 spring.datasource.username=klebermo spring.datasource.password=123 spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect spring.jpa.show-sql=false spring.jpa.hibernate.ddl-auto=create If you really need access to a SessionFactory and that is basically for the same datasource, then you can do the following (which is also documented here although … Read more
