JPA加入两个次表

我在这五个表

REF_CT   REF_CT_L  REF_ST  REF_ST_L 
======   ========  ======  ======== 
CT_ID   CT_ID   ST_ID   ST_ID 
ST_ID   LANGUAGE_ID  NAME   LANGUAGE_ID 
NAME   NAME   REF_CODE  NAME 
REF_CODE  DESCRIPTION     DESCRIPTION 


REF_LANGUAGE 
============ 
LANGUAGE_ID 
LOCALE_CODE 
NAME

通过使用JPA，我创建了这三个实体类：

类common.contact.City

@Entity 
@Table(name = "REF_CT") 
@SecondaryTable(name = "REF_CT_L") 
public class City implements Reference { 
    @Id 
    @Column(name = "CT_ID") 
    @TableGenerator(name = "TABLE_GEN", table = "SYS_SEQ", 
     pkColumnName = "SEQ_NAME", valueColumnName = "SEQ_VALUE", pkColumnValue = "CITY_SEQ") 
    @GeneratedValue(strategy = GenerationType.TABLE, generator = "TABLE_GEN") 
    private Integer id; 

    @Column(name = "NAME") 
    private String name; 

    @Column(table = "REF_CT_L", name = "NAME") 
    private String value; 

    @Column(name = "REF_CODE") 
    private String refCode; 

    @ManyToOne(targetEntity = Language.class) 
    @JoinColumn(table = "REF_CT_L", name = "LANGUAGE_ID") 
    private Language language; 

    @ManyToOne(targetEntity = State.class, optional = true) 
    @JoinColumn(name = "ST_ID", referencedColumnName = "ST_ID") 
    private State state;

类common.contact.State

@Entity 
@Table(name = "REF_ST") 
@SecondaryTable(name = "REF_ST_L") 
public class State implements Reference { 
    @Id 
    @Column(name = "ST_ID") 
    @TableGenerator(name = "TABLE_GEN", table = "SYS_SEQ", 
     pkColumnName = "SEQ_NAME", valueColumnName = "SEQ_VALUE", pkColumnValue = "STATE_SEQ") 
    @GeneratedValue(strategy = GenerationType.TABLE, generator = "TABLE_GEN") 
    private Integer id; 

    @Column(name = "NAME") 
    private String name; 

    @Column(table = "REF_ST_L", name = "NAME") 
    private String value; 

    @Column(name = "REF_CODE") 
    private String refCode; 

    @OneToMany(targetEntity = City.class, mappedBy = "state") 
    private Set<City> cities; 

    @ManyToOne(targetEntity = Language.class) 
    @JoinColumn(table = "REF_ST_L", name = "LANGUAGE_ID", unique = true, referencedColumnName = "LANGUAGE_ID") 
    private Language language;

类common.system.Language

@Entity 
@Table(name = "SYS_LANGUAGE") 
public class Language implements BaseEntity { 
    @Id 
    @Column(name = "LANGUAGE_ID") 
    @TableGenerator(name = "TABLE_GEN", table = "SYS_SEQ", 
     pkColumnName = "SEQ_NAME", valueColumnName = "SEQ_VALUE", pkColumnValue = "LANGUAGE_SEQ") 
    @GeneratedValue(strategy = GenerationType.TABLE, generator = "TABLE_GEN") 
    private Integer id; 

    @Column(name = "LOCALE_CODE") 
    private String locale; 

    @Column(name = "NAME") 
    private String name;

但是，当我试图运行此查询

select city from City city where city.id = 1

我得到这个错误：

org.hibernate.HibernateException: More than one row with the given identifier was found: 10, for class: common.contact.State

仅供参考，添加了以下数据：

REF_CT

CT_ID ST_ID NAME REF_CODE 
===== ===== ==== ======== 
    1  10 CHERAS  CHE

REF_CT_L

CT_ID LANGUAGE_ID NAME  DESCRIPTION 
===== =========== ====  =========== 
    1   1  BANDAR CHERAS CHERAS BARU 
    1   2  CHERAS TOWN NEW CHERAS

REF_ST

ST_ID NAME  REF_CODE 
===== ====  ======== 
    10 SELANGOR SEL

REF_ST_L

ST_ID LANGUAGE_ID  NAME  DESCRIPTION 
===== ===========  ====  =========== 
    10   1  SELANGOR SELANGOR BARU 
    10   2  SERIANGOR NEW SERIANGOR

REF_LANGUAGE

LANGUAGE_ID LOCALE_CODE NAME 
=========== =========== ==== 
    1   ms_En  Malay 
    2   en_US  English

生成的SQL是：

SELECT state0_.st_id AS st1_50_0_, 
     state0_.NAME AS name50_0_, state0_.ref_code AS ref4_50_0_, 
     state0_1_.language_id AS language2_51_0_, state0_1_.NAME AS name51_0_ 
    FROM ref_st state0_ LEFT OUTER JOIN ref_st_l state0_1_ 
     ON state0_.st_id = state0_1_.st_id 
WHERE state0_.st_id = 10;

感谢您的帮助！

来源

2012-08-30 Faizal Sidek

由于您将City - > State关系设置为可选，您的代码正在生成LEFT JOIN。将其更改为不可为空，并且应该获得应解析返回的多行的内部联接。

common.contact.City - >

@ManyToOne(targetEntity = State.class, optional = false) 
@JoinColumn(name = "ST_ID", referencedColumnName = "ST_ID", nullable = false) 
private State state;

来源

2012-08-30 21:30:49

问题仍然存在。它仍然显示找到了多于一行的给定标识符：10，for class：common.contact.State –

您能否显示查询生成的SQL以确认它不再执行LEFT JOIN？ –

“REF_ST” 与 “REF_ST_L” 一个一对多的关系。这意味着“REF_ST_L”不能被映射为辅助表（这意味着一对一的关系）。

相同的逻辑对“REF_CT” - >“REF_CT_L”有效。

来源

2013-09-06 14:07:35 GFonte

JPA加入两个次表

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