1、@ManyToOne

@ManyToOne(fetch = FetchType.EAGER)
@NotFound(action= NotFoundAction.IGNORE)
@JoinColumn(name = "country", insertable = false, updatable = false)
private StdPowerDict country;

• 主表的country字段
  
• 对应 StdPowerDict 实体的表
  

2、@ManyToMany

@ManyToMany(cascade = CascadeType.MERGE, fetch = FetchType.EAGER)
@JoinTable(name = "idb_std_power_engin_cate_v1", joinColumns = {
          @JoinColumn(name = "project_id", referencedColumnName = "id")}, inverseJoinColumns = {
          @JoinColumn(name = "cate_id", referencedColumnName = "id")})
private Set<StdPowerDict> cates;

• @JoinTable ：里面填写中间表名称
• @JoinColumn(name = “project_id”, referencedColumnName = “id”)：主表的id对应中间表的project_id
• inverseJoinColumns = {@JoinColumn(name = “cate_id”, referencedColumnName = “id”)}：StdPowerDict表对应中间表cate_id

数据库关系图例

• 主表
  
• StdPowerDict 实体表
  
• 中间表