在mysql休眠中保存子实体时忽略唯一约束

Question

I have two tables. Consider them as below. Person has OneToMany relationship with Phone.

create table Person(
  id varchar,
  name varchar
);

create table Phone(
  id varchar,
  name varchar,
  person_id varchar,
  UNIQUE KEY `unq` (`name`)
  FOREIGN KEY (person_id) REFERENCES Person(id)
);

Now Java Code looks as below.

Person person = new Person();
Phone phone = new Phone();
phone.setPerson(person);
phoneRepository.save(phone);

Query ignores unique constraint on the child table while insertion. It is saving multiple duplicate entries

What seems to be causing issue? Is it expected behavior?

Answer 1

You have to store existing Person entity

Instead to instantiate a new entity

Person person = new Person();

try to read existing entity

Person existingPerson = personRepository.findOneByName(name);

and set the existing entity to your phone

phoneRepository.save(existingPerson)