Question

我有一个简单的银行应用程序，其中有“帐户”和“交易”实体。一个帐户保留提款和存款交易（它们可以在两个帐户之间或account＆ATM之间（在相应字段中为空）。我使用@ManyToOne和@OneToMany批注，并希望将字段fromAccount和toAccount都保存在事务表ID-s中，但出现异常，您可以在下面看到。我了解发生这种情况是因为在同一字段（account_id）上进行了映射，但是如果我应该使用id字段怎么解决？我的代码示例：

public class Account {
@OneToMany(fetch = FetchType.LAZY,
        mappedBy = "fromAcc",
        cascade = CascadeType.ALL)
private List<Transaction> withdrawTransactions = new ArrayList<>();

@OneToMany(fetch = FetchType.LAZY,
        mappedBy = "toAcc",
        cascade = CascadeType.ALL)
private List<Transaction> depositTransactions = new ArrayList<>();

和

public class Transaction {
@ManyToOne
@JoinColumn(name = "account_id")
private Account fromAcc;
@ManyToOne
@JoinColumn(name = "account_id")
private Account toAcc;

我得到的异常：

 Exception in thread "main" javax.persistence.PersistenceException: [PersistenceUnit: BankAppSimple] Unable to build Hibernate SessionFactory
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.persistenceException(EntityManagerFactoryBuilderImpl.java:1012)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:938)
at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:56)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:79)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
at bank.app.simple.util.JpaUtil.getEntMngFactoryInstance(JpaUtil.java:18)
at bank.app.simple.util.JpaUtil.createEntityManager(JpaUtil.java:30)
at bank.app.simple.daoimpl.ExchangeRateDaoImpl.isCurrencyExist(ExchangeRateDaoImpl.java:19)
at bank.app.simple.serviceimpl.ExchangeRateServiceImpl.addRate(ExchangeRateServiceImpl.java:19)
at bank.app.simple.Main.fillTables(Main.java:46)
at bank.app.simple.Main.main(Main.java:26)

和

Caused by: org.hibernate.MappingException: Repeated column in mapping for entity: bank.app.simple.entity.Transaction column: account_id (should be mapped with insert="false" update="false")
at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:862)
at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:880)
at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:902)
at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:634)
at org.hibernate.mapping.RootClass.validate(RootClass.java:267)
at org.hibernate.boot.internal.MetadataImpl.validate(MetadataImpl.java:343)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:461)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:935)
... 9 more

Answer 1

我认为您忘记在Category实体中设置联接列。只需将RSpec::Matchers.define :be_successful do match do |result| result.status == :success && result.offers.length > 0 && result.comments.empty? end failure_message do |result| "Should have #{result} equal to be successful" end failure_message_when_negated do |result| "Should not have #{result} to be successful" end end和Transaction替换为事务表中的相应列名即可。

FROM_ACC_COLUMN

在这种情况下，我个人不愿意TO_ACC_COLUMN，而尝试public class Transaction { @ManyToOne @JoinColumn(name = "FROM_ACC_COLUMN", referencedColumnName = "account_id") private Account fromAcc; @ManyToOne @JoinColumn(name = "TO_ACC_COLUMN", referencedColumnName = "account_id") private Account toAcc; }。

Answer 2

如果有人感兴趣，对我有用的解决方案是使用@ManyToOne批注重命名实体中的映射字段，并在“ account_id” +“ referencedColumnName =“ account_id””之前添加前缀：

@ManyToOne
@JoinColumn(name = "from_account_id", referencedColumnName = "account_id") // add from_
private Account fromAcc;
@ManyToOne
@JoinColumn(name = "to_account_id", referencedColumnName = "account_id") // add to_
private Account toAcc;

@ t4dohx，谢谢您的指教！

使用Hibernate将一个实体映射到一个表的不同列

2 个答案: