Unidirectional bags

package org.example.demo.hibernate;

import java.util.ArrayList;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Persistence;

public class Test {
    public static void main(String[] args) throws Exception {
        EntityManagerFactory factory = Persistence.createEntityManagerFactory("test");
        EntityManager entityManager = factory.createEntityManager();

        Person person = new Person();
        person.getPhones().add(new Phone("landline", "028-234-9876"));
        person.getPhones().add(new Phone("mobile", "072-122-9876"));

        entityManager.getTransaction().begin();
        entityManager.persist(person);
        entityManager.flush();
        person.phones.remove(0);
        entityManager.getTransaction().commit();

        entityManager.clear();

        entityManager.close();
        factory.close();
    }

    @Entity(name = "Person")
    public static class Person {
        @Id
        @GeneratedValue
        private Long id;
        @OneToMany(cascade = CascadeType.ALL)
        private List<Phone> phones = new ArrayList<>();

        public Person() {
        }

        public Person(Long id) {
            this.id = id;
        }

        public List<Phone> getPhones() {
            return phones;
        }
    }

    @Entity(name = "Phone")
    public static class Phone {
        @Id
        @GeneratedValue
        private Long id;

        private String type;

        @Column(name = "`number`")
        private String number;

        public Phone() {
        }

        public Phone(String type, String number) {
            this.type = type;
            this.number = number;
        }

        public Long getId() {
            return id;
        }

        public String getType() {
            return type;
        }

        public String getNumber() {
            return number;
        }
    }
}

生成 SQL

alter table Person_Phone drop constraint FKr38us2n8g5p9rj0b494sd3391
alter table Person_Phone drop constraint FK2ex4e4p7w1cj310kg2woisjl2
drop table if exists Person cascade
drop table if exists Person_Phone cascade
drop table if exists Phone cascade
drop sequence if exists hibernate_sequence

create sequence hibernate_sequence start 1 increment 1
create table Person (id int8 not null, primary key (id))
create table Person_Phone (Person_id int8 not null, phones_id int8 not null)
create table Phone (id int8 not null, "number" varchar(255), type varchar(255), primary key (id))
alter table Person_Phone add constraint UK_9uhc5itwc9h5gcng944pcaslf unique (phones_id)
alter table Person_Phone add constraint FKr38us2n8g5p9rj0b494sd3391 foreign key (phones_id) references Phone
alter table Person_Phone add constraint FK2ex4e4p7w1cj310kg2woisjl2 foreign key (Person_id) references Person
select nextval ('hibernate_sequence')
select nextval ('hibernate_sequence')
select nextval ('hibernate_sequence')
insert into Person (id) values (1)
insert into Phone ("number", type, id) values ('028-234-9876', 'landline', 2)
insert into Phone ("number", type, id) values ('072-122-9876', 'mobile', 3)
insert into Person_Phone (Person_id, phones_id) values (1, 2)
insert into Person_Phone (Person_id, phones_id) values (1, 3)
delete from Person_Phone where Person_id=1
insert into Person_Phone (Person_id, phones_id) values (1, 3)

Bidirectional bags

package org.example.demo.hibernate;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import javax.persistence.OneToMany;
import javax.persistence.Persistence;

public class Test {
    public static void main(String[] args) throws Exception {
        EntityManagerFactory factory = Persistence.createEntityManagerFactory("test");
        EntityManager entityManager = factory.createEntityManager();

        Person person = new Person();
        person.addPhone(new Phone("landline", "028-234-9876"));
        person.addPhone(new Phone("mobile", "072-122-9876"));

        entityManager.getTransaction().begin();
        entityManager.persist(person);
        entityManager.flush();
        person.removePhone(person.getPhones().get(0));
        entityManager.getTransaction().commit();

        entityManager.clear();

        entityManager.close();
        factory.close();
    }

    @Entity(name = "Person")
    public static class Person {
        @Id
        @GeneratedValue
        private Long id;
        @OneToMany(mappedBy = "person", cascade = CascadeType.ALL)
        private List<Phone> phones = new ArrayList<>();

        public Person() {
        }

        public Person(Long id) {
            this.id = id;
        }

        public List<Phone> getPhones() {
            return phones;
        }

        public void addPhone(Phone phone) {
            phones.add(phone);
            phone.setPerson(this);
        }

        public void removePhone(Phone phone) {
            phones.remove(phone);
            phone.setPerson(null);
        }
    }

    @Entity(name = "Phone")
    public static class Phone {
        @Id
        @GeneratedValue
        private Long id;

        private String type;

        @Column(name = "`number`")
        private String number;

        @ManyToOne
        private Person person;

        public Phone() {
        }

        public Phone(String type, String number) {
            this.type = type;
            this.number = number;
        }

        public Long getId() {
            return id;
        }

        public String getType() {
            return type;
        }

        public String getNumber() {
            return number;
        }

        public Person getPerson() {
            return person;
        }

        public void setPerson(Person person) {
            this.person = person;
        }

        @Override
        public boolean equals(Object o) {
            if (this == o) {
                return true;
            }
            if (o == null || getClass() != o.getClass()) {
                return false;
            }
            Phone phone = (Phone) o;
            return Objects.equals(number, phone.number);
        }

        @Override
        public int hashCode() {
            return Objects.hash(number);
        }
    }
}

生成 SQL

alter table Phone drop constraint FKmw13yfsjypiiq0i1osdkaeqpg
drop table if exists Person cascade
drop table if exists Phone cascade
drop sequence if exists hibernate_sequence

create sequence hibernate_sequence start 1 increment 1
create table Person (id int8 not null, primary key (id))
create table Phone (id int8 not null, "number" varchar(255), type varchar(255), person_id int8, primary key (id))
alter table Phone add constraint FKmw13yfsjypiiq0i1osdkaeqpg foreign key (person_id) references Person
select nextval ('hibernate_sequence')
select nextval ('hibernate_sequence')
select nextval ('hibernate_sequence')
insert into Person (id) values (1)
insert into Phone ("number", person_id, type, id) values ('028-234-9876', 1, 'landline', 2)
insert into Phone ("number", person_id, type, id) values ('072-122-9876', 1, 'mobile', 3)
update Phone set "number"='028-234-9876', person_id=NULL, type='landline' where id=2

Bidirectional bag with orphan removal

如果第 44 行加上 orphanRemoval = true 则生成 SQL

alter table Phone drop constraint FKmw13yfsjypiiq0i1osdkaeqpg
drop table if exists Person cascade
drop table if exists Phone cascade
drop sequence if exists hibernate_sequence

create sequence hibernate_sequence start 1 increment 1
create table Person (id int8 not null, primary key (id))
create table Phone (id int8 not null, "number" varchar(255), type varchar(255), person_id int8, primary key (id))
alter table Phone add constraint FKmw13yfsjypiiq0i1osdkaeqpg foreign key (person_id) references Person
select nextval ('hibernate_sequence')
select nextval ('hibernate_sequence')
select nextval ('hibernate_sequence')
insert into Person (id) values (1)
insert into Phone ("number", person_id, type, id) values ('028-234-9876', 1, 'landline', 2)
insert into Phone ("number", person_id, type, id) values ('072-122-9876', 1, 'mobile', 3)
delete from Phone where id=2