check if a record exist in database using spring boot and JPA repository

Question

I want to check whether a record exist in database before I save. If possible I want to check using two fields i.e regno and name. method to be like checkIfRegNoAndNameExists(){}. my model class

@Entity
public class Car {
     @Id
    @GeneratedValue
    private int id;
    private String regno;
    private String name;
    // getters, setters, ...
}

my dao class

import org.springframework.data.jpa.repository.JpaRepository;
public interface ProgramDao extends JpaRepository<CarModel, Integer> {
}

my service class

@Service
public class CarServiceImpl implements ProgramService {
    @Autowired
    private CarDao carDao;
    @Override
    public carModel saveProgram(carModel car) { 
        return carDao.save(program);
    }
}

Solution 1

interface ProgramDao extends JpaRepository<CarModel, Integer> {
    boolean existsByRegnoAndName(String regno, String name);
}

Solution 2

You can also use exists method:

1. Create an object you're looking for and set desired fields.
2. convert it to Example.

3. Use repository's exists method.

   CarModel carModel = new CarModel();
   carModel.setRegno(regno);
   carModel.setName(name);
   repo.exists(Example.of(carModel));
   

This is a generic way, that does not require creating a bunch of methods in repository.