如何在不止一个JPA值的情况下使用mappingBy [英] How to use mappedBy with more than one value JPA

问题描述

我有2张桌子: 货币和汇率

I have 2 tables: Currency and Rate

币种的主键由Rate中的eighboring的inputCurrency和outputCurrency引用.

The currency's primary key is referenced by the inputCurrency and outputCurrency foreigh keys in the Rate.

我如何映射这些以便进行层叠?

How can I map these in order to cascadeALL?

我尝试使用Rate(包含foreeigh键的表)

I tried in Rate (the table that contains the foreigh keys)

@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "INPUT_CURRENCY")
private Currency inputCurrency;

@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "OUTPUT_CURRENCY")
private Currency ouputCurrency;

但是，如果我从货币中删除项目，则会导致主键冲突.我无法删除货币，因为它由Rate中的inputCurrency或outputCurrency引用.

But if I delete an item from currency It results a primary key violation.I can't remove a Currency becouse it is referenced by inputCurrency or outputCurrency in Rate.

如果我想用Currency注释汇率列表，我怎么能说mapledBy ="inputCurrency"和"outputCurrency"?

If I want to annotate the list of rates in Currency, how can I say mappedBy = "inputCurrency" and "outputCurrency" ?

@OneToMany(cascade = CascadeType.ALL,mappedBy ="inputCurrency,outputCurrency")
List<Rate> rates;

推荐答案

该解决方案使用两种汇率列表:一种用于fk inputCurrency 另一个用于fk outputCurrency

The solution is using two list of rates in Currency: one for the fk inputCurrency and another for the fk outputCurrency

@OneToMany(cascade = CascadeType.ALL,mappedBy ="inputCurrency")
List<Rate> ratesIC;

@OneToMany(cascade = CascadeType.ALL,mappedBy ="outputCurrency")
List<Rate> ratesOC;

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