Spring data-JPA repository.save() is not updating entity - spring

Question

My classes are like..
Employee Entity:
import javax.persistence.Entity;
import lombok.Data;
import org.hibernate.annotations.DynamicUpdate;
import javax.persistence.PrePersist;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;
#Entity
#Data
#DynamicUpdate
#EntityListeners(AuditingEntityListener.class)
#Table(name = "tbl_employee", indexes = {
#Index(name = "idx_employee_status", columnList = "status"),
#Index(name = "idx_employee_createdAt", columnList = "createdAt") })
public class Employee {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
protected Long id;
private String name;
private String remarks;
private String status;
#PrePersist
public void setCreatedAt() {
this.createdAt = OffsetDateTime.now();
}
}
Repository:
public interface EmployeeRepository extends CrudRepository<Employee, Long>, PagingAndSortingRepository<Employee, Long>{
}
Service methods:
createEmployee(){
Employee employee = new Employee();
employee.setName("John");
employee.setRemarks("Very Good Performance");
employeeRepository.save(employee);
}
updateEmployee(){
Employee employee = employeeRepository.findById(1L); // Id is long
employee.setName("Thomas");
employee.setRemarks("Above average Performance");
employeeRepository.save(employee);
}
createEmployee() is working and data is getting saved in DB (MySQL), but updateEmployee() is not. No sql query is generated in the eclipse console.
AM I missing something in configuration?

Answer 1

Make sure that the service methods are annotated with #Transactional.
Otherwise the hibernate cannot track changes which are needed for #DynamicUpdate.
Alternatively you can also try to remove the annotation.

Answer 2

Hibernate/JPA only access the database when it has to.
In the create variant it needs to return an instance with a updated ID value. The id value gets generated by the database when the insert is performed.
Therefore the insert is performed immediately.
In the other case no information from the database is required.
Therefore Hibernate/JPA only marks the entity as dirty and moves on.
Only when the transaction ends the update is actually performed.