@Entity
public class Shirt implements Serializable {

    @Id
    @Size(max=9)
    private String id;

    @ElementCollection
    @CollectionTable(
        name = "SHIRT_COLORS",
        joinColumns=@JoinColumn(name = "id", referencedColumnName = "id")
    )
    @Column(name="color")
    private List<String> colors = new ArrayList<String>();
    ...

https://stackoverflow.com/questions/22075199/jpa-elementcollection-list-specify-join-column-name

@Column(nullable=false) 是生成模式的指令。从该类生成的数据库列将在实际数据库中标记为不可空。

optional=false 是一条运行时指令。它的主要功能与懒加载有关。除非你记得设置 optional=false，否则你就无法懒加载一个非集合映射实体（因为 Hibernate 不知道那里应该有一个代理还是一个空值，除非你告诉它空值是不可能的，所以它可以生成一个代理）。

https://stackoverflow.com/questions/3331907/what-is-the-difference-between-manytooneoptional-false-vs-columnnullable-f

This is known issue in Hibernate, see https://hibernate.atlassian.net/browse/HHH-8805

Solution is to add @org.hibernate.annotations.ForeignKey(name = "none") on the mapped side.

class Parent {

  @OneToMany(mappedBy="parent", cascade=CascadeType.ALL, orphanRemoval=true)
  @OrderColumn(name="childIndex")
  @org.hibernate.annotations.ForeignKey(name = "none")
  public List<Child> getChildren() {
    return children;
  }

}

Note: Prefer the JPA 2.1 introduced javax.persistence.ForeignKey instead. The native annotation is deprecated.

answerd by Bustanil Arifin and sophros How do I disable Hibernate foreign key constraint on a bidirectional association?