Spring JPA Versioned Entity hibernate errors - spring

Question

Is there a better way to update a versioned entity other than to catch exception and retrying ?
Below is the code
#Entity
#AllArgsConstructor
#Builder
#NoArgsConstructor
#Data
#IdClass(com.test.domain.EmployeeKey.class)
public class Employee {
#Id
private Integer employeeId;
private String name;
private Double commission;
#Id
private LocalDate inputDate;
#Version
private Integer version;
}
public class EmployeeKey implements Serializable {
private Integer employeeId;
private java.time.LocalDate inputDate;
}
#SpringBootApplication
#Slf4j
public class SampleApplication {
public static void main(final String[] args) {
SpringApplication.run(SampleApplication.class, args);
}
#Component
public class AppStartupRunner implements ApplicationRunner {
#Autowired
EmployeeRepo employeeRepo;
#Override
public void run(ApplicationArguments args) throws Exception {
log.info("Your application started with option names : {}", args.getOptionNames());
List<Employee> empList = new ArrayList();
Employee employeeComm1 = Employee.builder().employeeId(1).name("Sam").commission(100.45).inputDate(LocalDate.of(2019,10,01)).build();
Employee employeeComm2 = Employee.builder().employeeId(1).name("Sam").commission(87.54).inputDate(LocalDate.of(2019,10,01)).build();
Employee employeeComm3 = Employee.builder().employeeId(2).name("John").commission(56.78).inputDate(LocalDate.of(2019,10,01)).build();
Employee employeeComm4 = Employee.builder().employeeId(3).name("Katie").commission(65.23).inputDate(LocalDate.of(2019,10,01)).build();
empList.add(employeeComm1);
empList.add(employeeComm3);
empList.add(employeeComm4);
empList.add(employeeComm2);
// employeeRepo.saveAll(empList);
for (Employee emp: empList) {
try {
employeeRepo.save(emp);
}
catch(Exception e) {
if (employeeRepo.findByEmployeeIdAndInputDate(emp.getEmployeeId(), emp.getInputDate()).isPresent()) {
Employee empFromDb = employeeRepo.findByEmployeeIdAndInputDate(emp.getEmployeeId(), emp.getInputDate()).get();
empFromDb.setCommission(emp.getCommission());
empFromDb.setName(emp.getName());
employeeRepo.save(empFromDb);
}
}
}
}
}
}
Output shown below
Hibernate: insert into employee (commission, name, version, employee_id, input_date) values (?, ?, ?, ?, ?)
Hibernate: insert into employee (commission, name, version, employee_id, input_date) values (?, ?, ?, ?, ?)
Hibernate: insert into employee (commission, name, version, employee_id, input_date) values (?, ?, ?, ?, ?)
Hibernate: insert into employee (commission, name, version, employee_id, input_date) values (?, ?, ?, ?, ?)
2019-10-15 16:43:10.372 WARN 17216 --- [ main] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 1, SQLState: 23000
2019-10-15 16:43:10.372 ERROR 17216 --- [ main] o.h.engine.jdbc.spi.SqlExceptionHelper : ORA-00001: unique constraint (I706446.SYS_C008493) violated
Hibernate: select employee0_.employee_id as employee_id1_0_, employee0_.input_date as input_date2_0_, employee0_.commission as commission3_0_, employee0_.name as name4_0_, employee0_.version as version5_0_ from employee employee0_ where employee0_.employee_id=? and employee0_.input_date=?
Hibernate: select employee0_.employee_id as employee_id1_0_, employee0_.input_date as input_date2_0_, employee0_.commission as commission3_0_, employee0_.name as name4_0_, employee0_.version as version5_0_ from employee employee0_ where employee0_.employee_id=? and employee0_.input_date=?
Hibernate: select employee0_.employee_id as employee_id1_0_0_, employee0_.input_date as input_date2_0_0_, employee0_.commission as commission3_0_0_, employee0_.name as name4_0_0_, employee0_.version as version5_0_0_ from employee employee0_ where employee0_.employee_id=? and employee0_.input_date=?
Hibernate: update employee set commission=?, name=?, version=? where employee_id=? and input_date=? and version=?

Answer 1

I expect an hibernate to issue an update with Version column
incrementing
Your expectation is incorrect. You use version not as it is intended to be used. The purpose of versioning is to provide optimistic locking and not simply indicate how many times has the entity changed. The intended usage scenario is following: before updating an entity you should read it from the database, then modify, then save. Hibernate checks if the version you are trying to save is the same as in the database.
A) If the same, it will automatically increment version and save your entity, i.e. it will update the existing record in the database.
B) If the version in the entity you are trying to save is less than the version in the database, it means you are trying to save an outdated version. It means you are not aware of changes that were done in the meanwhile. In such case Hibernate will throw an exception.