Mapping Single Entity to Multiple Tables in JPA: Error

Question

I'm developing a Java Spring Boot Web App and am having an issue with mapping an entity to multiple tables. The two tables at hand are "Profile" and "Users". Users has the attribute "email", which I would like to be able to put into Profile. To do this, I use the @SecondaryTable annotation when creating the Profile Table in order to join the Users table with it. Here below is the Profile entity:

@Entity
@Table(name="Profile")
@SecondaryTable(name="Users", pkJoinColumns=@PrimaryKeyJoinColumn(name="userId"))
public class Profile {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="profileId")
    private long profileId;

    @OneToOne(targetEntity=SiteUser.class)
    @JoinColumn(name="user_id", nullable=false)
    private SiteUser user;
    
    @Column(name="about", length=1000)
    @Size(max=1000, message="{edit.profile.about.size}")
    private String about;
    
    @Column(name="email", table="Users")
    private String email;

    ...
}

And then here is the Users entity:

@Entity
@Table(name="Users")
@PasswordMatch(message="{register.repeatPassword.mismatch}")
public class SiteUser {
    
    @Id
    @Column(name="userId")
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Long userId;

    @Column(name="email", unique=true)
    @Email(message="{register.email.invalid}")
    @NotBlank(message="{register.email.invalid}")
    private String email;
    ...
}

The errors I'm getting are the following:

org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "alter table users add constraint FKce1xk9c9bdk7obdg7sva65g88 foreign key (user_id) references profile (profile_id)" via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlString(AbstractSchemaMigrator.java:559) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applySqlStrings(AbstractSchemaMigrator.java:504) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.applyForeignKeys(AbstractSchemaMigrator.java:433) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.performMigration(AbstractSchemaMigrator.java:249) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.tool.schema.internal.AbstractSchemaMigrator.doMigration(AbstractSchemaMigrator.java:114) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:184) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:320) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:462) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1237) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) ~[spring-orm-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:391) ~[spring-orm-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:378) ~[spring-orm-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1855) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1792) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:595) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1108) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:868) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
    at bcoreHW.App.main(App.java:27) ~[classes/:na]
Caused by: java.sql.SQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`dbName`.`#sql-8c_2b2`, CONSTRAINT `FKce1xk9c9bdk7obdg7sva65g88` FOREIGN KEY (`user_id`) REFERENCES `profile` (`profile_id`))
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:117) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.StatementImpl.executeInternal(StatementImpl.java:764) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.mysql.cj.jdbc.StatementImpl.execute(StatementImpl.java:648) ~[mysql-connector-java-8.0.18.jar:8.0.18]
    at com.zaxxer.hikari.pool.ProxyStatement.execute(ProxyStatement.java:95) ~[HikariCP-3.4.1.jar:na]
    at com.zaxxer.hikari.pool.HikariProxyStatement.execute(HikariProxyStatement.java) ~[HikariCP-3.4.1.jar:na]
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54) ~[hibernate-core-5.4.9.Final.jar:5.4.9.Final]
    ... 33 common frames omitted

I searched around and tried adding spring.jpa.hibernate.ddl-auto=update , but this did nothing. Any thoughts on why I'm getting this error would be much appreciated.

Answer 1

You use table Users actually in two entities - as a part of entity Profile and as an entity SiteUser . This is very problematic design. In particular this means that when you try to delete an entry of SiteUser , it may be a part of some entry Profile and thus you would want to delete a part of the Profile . A foreign key protects such deletion.

I'd suggest to check what you actually need.

1. Do you want to have a single entity that is stored in 2 tables? Then delete entity SiteUser ans use only entity Profile .
2. Do you want to have relatively independent entries in 2 tables, Profile and Users ? Then don't use 2 tables for single entity. Instead, for entity Profile use a single table Profile , and for relation to the User entities use a relation, depending on your goals @OneToOne or @OneToMany .