## 一對多保存 ~~~ Customer customer = new Customer(); customer.setCust_name("jack"); Linkman linkman = new Linkman(); linkman.setLink_name("秘書"); customer.getLinkmens().add(linkman); linkman.setCustomer(customer); entityManager.persist(customer); entityManager.persist(linkman); ~~~ ## 一對多級聯保存 ~~~ @OneToMany(targetEntity = Linkman.class, mappedBy = "customer", cascade = CascadeType.PERSIST) //設置級聯保存 private Set<Linkman> linkmens = new HashSet<>(); ~~~ 代碼: ~~~ Customer customer = new Customer(); customer.setCust_name("jack"); Linkman linkman1 = new Linkman(); linkman1.setLink_name("小王"); Linkman linkman2 = new Linkman(); linkman2.setLink_name("小張"); customer.getLinkmens().add(linkman1); customer.getLinkmens().add(linkman2); linkman1.setCustomer(customer); linkman2.setCustomer(customer); entityManager.persist(customer); ~~~ ## 普通刪除 ~~~ Linkman linkman = entityManager.find(Linkman.class, 7L); entityManager.remove(linkman); ~~~ ## 級聯刪除 ~~~ @OneToMany(targetEntity = Linkman.class, mappedBy = "customer", cascade = CascadeType.REMOVE) //設置級聯刪除 private Set<Linkman> linkmens = new HashSet<>(); ~~~ 當刪除customer的時候,linkman關聯的記錄也被刪除了. ~~~ Customer customer = entityManager.find(Customer.class, 6L); entityManager.remove(customer); ~~~