英文:
Hibernate doesn't creating Join Table on his own
问题
我想在我的实体之间建立多对多的关系。我希望Hibernate能自动生成这个表，但这似乎不会发生。
这是我的实体：
DrugsEntity：
@Entity@Table(name = "drugs", schema = "meds", catalog = "chinamed")public class DrugsEntity {@Id@Basic@Column(name = "id")private int id;@Basic@Column(name = "name_eng")private String nameEng;@ManyToMany()@JoinTable(name = "drug_symptom",joinColumns = { @JoinColumn(name = "drug_id", nullable = false) },inverseJoinColumns = { @JoinColumn(name = "symptom_id", nullable = false) })private Set<SymptomEntity> symptoms;}
SymptomsEntity：
@Entity@Table(name = "symptom", schema = "meds", catalog = "chinamed")public class SymptomEntity {@Id@GeneratedValueint id;@BasicString name;@Column@ManyToMany(mappedBy = "symptoms", cascade = CascadeType.ALL)Set<DrugsEntity> drugs;}
一些配置：
jpa:hibernate:ddl-auto: updateshow-sql: true
这样我可以看到Hibernate的SQL查询：
Hibernate: create table meds.diseases (disease_id int4 not null, drug_id int4, name varchar(255), primary key (disease_id))Hibernate: create table meds.drugs (id int4 not null, action_pharm varchar(255), action_tkm varchar(255), clinic varchar(255), contraindications varchar(255), form varchar(255), maker varchar(255), name_eng varchar(255), name_ru varchar(255), taking_method varchar(255), primary key (id))Hibernate: create table meds.herbal_drug (herbal_id int4 not null, drug_id int4, primary key (herbal_id))Hibernate: create table meds.pattern_drug (pattern_id int4 not null, drug_id int4, primary key (pattern_id))Hibernate: create table meds.symptom (id int4 not null, name varchar(255), primary key (id))Hibernate: alter table if exists symptom_drug add constraint FKl7jx9kgpfiunb1r5neejqi1in foreign key (drug_id) references meds.symptomHibernate: alter table if exists symptom_drug add constraint FKimmnf4263cgg3yg46i90tkn1g foreign key (symptom_id) references meds.drugsHibernate: alter table if exists symptom_drugs add constraint FKnvs2tystmth11i573t29rtayk foreign key (drugs_id) references meds.drugsHibernate: alter table if exists symptom_drugs add constraint FKng4i6ig5nr2laew225ttfnrb9 foreign key (symptom_entity_id) references meds.symptom
正如我所看到的，Hibernate甚至没有尝试创建这个表。
使用的方言：org.hibernate.dialect.PostgreSQL10Dialect
如何使Hibernate能够自动创建这个表？
附注：已经查看了这个链接 https://stackoverflow.com/questions/52910621/hibernate-doesnt-create-join-table 但这不是我的情况，我想。
已解决：
问题在于这个表已经被创建。我可能可以在Hibernate的查询中注意到一些有趣的东西：在"drug_symptom"表名之前没有前缀"meds"。
所以它在数据库的"public"模式中创建了表。
我通过添加default_schema来解决这个问题。
spring:jpa:hibernate:ddl-auto: updateshow-sql: trueproperties:hibernate:default_schema: meds
但我也可以在@JoinTable注释中使用"schema"参数。
英文:
I want to make many-to-many relationship between my entities.
I want hibernate to generate this table automaticaly, but it's not gonna happen.
Here is my entities:
DrugsEntity:
@Entity@Table(name = "drugs", schema = "meds", catalog = "chinamed")public class DrugsEntity {@Id@Basic@Column(name = "id")private int id;@Basic@Column(name = "name_eng")private String nameEng;@ManyToMany()@JoinTable(name = "drug_symptom",joinColumns = { @JoinColumn(name = "drug_id",nullable = false) },inverseJoinColumns = { @JoinColumn(name = "symptom_id", nullable = false) })private Set<SymptomEntity> symptoms;}
SymptomsEntity:
@Entity@Table(name = "symptom",schema = "meds", catalog = "chinamed")public class SymptomEntity {@Id@GeneratedValueint id;@BasicString name;@Column@ManyToMany(mappedBy = "symptoms",cascade = CascadeType.ALL)Set<DrugsEntity> drugs;}
Some configuration:
jpa:hibernate:ddl-auto: updateshow-sql: true
So i can see hibernate sql queries:
Hibernate: create table meds.diseases (disease_id int4 not null, drug_id int4, name varchar(255), primary key (disease_id))Hibernate: create table meds.drugs (id int4 not null, action_pharm varchar(255), action_tkm varchar(255), clinic varchar(255), contraindications varchar(255), form varchar(255), maker varchar(255), name_eng varchar(255), name_ru varchar(255), taking_method varchar(255), primary key (id))Hibernate: create table meds.herbal_drug (herbal_id int4 not null, drug_id int4, primary key (herbal_id))Hibernate: create table meds.pattern_drug (pattern_id int4 not null, drug_id int4, primary key (pattern_id))Hibernate: create table meds.symptom (id int4 not null, name varchar(255), primary key (id))Hibernate: alter table if exists symptom_drug add constraint FKl7jx9kgpfiunb1r5neejqi1in foreign key (drug_id) references meds.symptomHibernate: alter table if exists symptom_drug add constraint FKimmnf4263cgg3yg46i90tkn1g foreign key (symptom_id) references meds.drugsHibernate: alter table if exists symptom_drugs add constraint FKnvs2tystmth11i573t29rtayk foreign key (drugs_id) references meds.drugsHibernate: alter table if exists symptom_drugs add constraint FKng4i6ig5nr2laew225ttfnrb9 foreign key (symptom_entity_id) references meds.symptom
As I see hibernate dont even try to create this table.
Using dialect: org.hibernate.dialect.PostgreSQL10Dialect
How can achive that hibernate create that table on his own?
P.S: already looked this link https://stackoverflow.com/questions/52910621/hibernate-doesnt-create-join-table But it isn't my case, i suppose.
SOLVED:
The problem was that this table was alredy crated. And I probably coud notice something interesting in hibernate's queries: there was no prefix "meds" before drug_symptom table name.
So it created table in "public" schema of databese.
Solved that this way: added default_schema
spring:jpa:hibernate:ddl-auto: updateshow-sql: trueproperties:hibernate:default_schema: meds
But also I could use "schema" parameter in annotation @JoinTable.
答案1
得分: 2
从drugs字段中删除@Column注解，并在DrugsEntity.symptoms上定义级联类型，因为它是关系的拥有方。
@JoinTable和@ManyToMany注解都不应与@Column一起使用，因为映射必须通过其自身的定义进行。在同一字段上使用这两个注解会使Hibernate混淆。
您的映射应如下所示：
@Entity@Table(name = "drugs", schema = "meds", catalog = "chinamed")public class DrugsEntity {@Id@Column(name = "id")private int id;@Basic@Column(name = "name_eng")private String nameEng;@ManyToMany(cascade = CascadeType.ALL)@JoinTable(name = "drug_symptom",joinColumns = @JoinColumn(name = "drug_id", nullable = false),inverseJoinColumns = @JoinColumn(name = "symptom_id", nullable = false))private Set<SymptomEntity> symptoms;}
和
@Entity@Table(name = "symptom", schema = "meds", catalog = "chinamed")public class SymptomEntity {@Id@GeneratedValueint id;@BasicString name;@ManyToMany(mappedBy = "symptoms")Set<DrugsEntity> drugs;}
祝您编码顺利！
英文:
Remove @Column annotation from drugs field and define cascade type on DrugsEntity.symptoms, as it is the owning side of relationship.
Both @JoinTable and @ManyToMany annotations should not be used with @Column, as the mapping must be made by it's own definition. Hibernate gets confused about both annotations on same field.
Your mapping should be:
@Entity@Table(name = "drugs", schema = "meds", catalog = "chinamed")public class DrugsEntity {@Id@Column(name = "id")private int id;@Basic@Column(name = "name_eng")private String nameEng;@ManyToMany(cascade = CascadeType.ALL)@JoinTable(name = "drug_symptom",joinColumns = @JoinColumn(name = "drug_id",nullable = false),inverseJoinColumns = @JoinColumn(name = "symptom_id", nullable = false))private Set<SymptomEntity> symptoms;}
and
@Entity@Table(name = "symptom",schema = "meds", catalog = "chinamed")public class SymptomEntity {@Id@GeneratedValueint id;@BasicString name;@ManyToMany(mappedBy = "symptoms")Set<DrugsEntity> drugs;}
Good coding!
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