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我正在做一个学校项目，目标是为一个虚构的药房制作一个 JavaEE 应用程序。

由于一种药物可以治疗一种或多种疾病，一种疾病可以由一种或多种药物治疗，我认为这是一个侧面和一个侧面的@OneToMany关系。我也有实体。一个病人可能患有一种或多种疾病，一种疾病可能折磨许多病人。我对我的类进行了如下编码，但是当我尝试从实体生成表时，我的类和类之间出现了不兼容的映射异常。我在 Eclipse 中使用 GlassFish 服务器和 Derby 连接（一切都配置良好，所以这绝对是代码问题）。我的课程如下：Drug@ManyToManyDiseasePatientDrugDisease

public class Drug implements Serializable{
@OneToMany(targetEntity = Disease.class, mappedBy = "Cures_For_This_Disease")
private List<Disease> Diseases_Cured_By_This_Drug;
//other fields such as the name, price and origin of the drug
}

public class Disease implements Serializable{
@ManyToMany(targetEntity = Drug.class)
private List<Drug> Cures_For_This_Disease;
@ManyToMany(targetEntity = Patient.class)
private List<Patient> Afflicted_Patients;
//other fields such as name of disease etc.
}

public class Patient implements Serializable{
@OneToMany(targetEntity = Disease.class, mappedBy = "AfflictedPatients")
private List<Disease> Current_Diseases;
//other fields such as Patient name, social sec. nubmer etc
}

我究竟做错了什么？

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1 回答 1

2

您应该在和类中有@ManyToMany注释。DrugPatient

public class Drug implements Serializable{
    @ManyToMany
    private List<Disease> Diseases_Cured_By_This_Drug;

}

public class Disease implements Serializable{
    @ManyToMany(mappedBy="Diseases_Cured_By_This_Drug")
    private List<Drug> Cures_For_This_Disease;
}

这应该在两个对应的表之间创建一个连接表。

于 2013-05-19T16:07:43.523 回答