我有
-
USER(user_id),
-
LOCATION(location_id,country_id,state_id,city_id),
-
COUNTRY(country_id,name),
-
STATE(state_id,name)
-
CITY(city_id,name) .
USER_LOCATION表之间的USER和LOCATION之间存在多对多关系 . 这是我在User.java中的映射:
//bi-directional many-to-many association to Location
@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(
name="user_location"
, joinColumns={
@JoinColumn(name="USER_ID")
}
, inverseJoinColumns={
@JoinColumn(name="LOCATION_ID")
}
)
private List<Location> locations;
当我保存USER时,我只有前端的USER.LOCATION.LOCATION_ID,而我没有其他LOCATION对象的字段 . 我只想插入USER_LOCATION表 . 但SpringDataJPA正试图 insert into LOCATION with INSERT INTO LOCATION (CITY_ID, COUNTRY_ID, STATE_ID) VALUES (?, ?, ?) bind => [null, null, null]
所有LOCATION,COUNTRY,STATE和CITY数据都预先填充在数据库中,我不想为这些表插入任何新记录 . 我怎样才能插入USER_LOCATION表?
1 回答
如果要将用户与现有位置相关联,则需要从数据库中实际获取现有的持久性位置,并将其设置为关系 .