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JPA实体字段的模型查找表_Jpa_Associations_Entity_Lookup_Relationships - Fatal编程技术网

JPA实体字段的模型查找表

JPA实体字段的模型查找表,jpa,associations,entity,lookup,relationships,Jpa,Associations,Entity,Lookup,Relationships,我正试图找到合适的关系,以便对JPA实体字段进行建模,该字段需要一个查找表(UI上的Comboxbox等价物)来从中选择值。下面是一个例子: @Entity public class Employee { @Id private int employeeId; private String name; private Department department; } 部门的实例如下: Id | Name -----------------------

我正试图找到合适的关系,以便对JPA实体字段进行建模,该字段需要一个查找表(UI上的Comboxbox等价物)来从中选择值。下面是一个例子:

@Entity
public class Employee {

    @Id
    private int employeeId;
    private String name;
    private Department department;
}

部门的实例如下:

Id    | Name
-----------------------
100   | Human Resources
101   | Sales
102   | Finances
对于员工,“部门”字段应该从上面的值中获取一个值。两个实体中对应字段的JPA注释应该是什么

谢谢


Sandeep Joseph

我认为您正在寻找一种从
员工
部门
的单向关系,类似这样:

@Entity
public class Employee {

    @Id
    private int employeeId;
    private String name;

    @ManyToOne
    @JoinColumn(name = "department_id", nullable = false)
    private Department department;
}
这意味着一名员工必须关联到一个部门,而一个部门可以关联到多个员工

如果您需要了解与部门关联的员工列表,则可以通过添加以下内容来实现双向关系:

@Entity
public class Department  {

    @Id
    private int id;
    private String name;

    @OneToMany(mappedBy = "department")
    private Collection<Employee> employees; 
}
@实体
公共课系{
@身份证
私有int-id;
私有字符串名称;
@OneToMany(mappedBy=“部门”)
私人收藏员工;
}

我认为您正在寻找一种从
员工
部门
的单向关系,类似这样:

@Entity
public class Employee {

    @Id
    private int employeeId;
    private String name;

    @ManyToOne
    @JoinColumn(name = "department_id", nullable = false)
    private Department department;
}
这意味着一名员工必须关联到一个部门,而一个部门可以关联到多个员工

如果您需要了解与部门关联的员工列表,则可以通过添加以下内容来实现双向关系:

@Entity
public class Department  {

    @Id
    private int id;
    private String name;

    @OneToMany(mappedBy = "department")
    private Collection<Employee> employees; 
}
@实体
公共课系{
@身份证
私有int-id;
私有字符串名称;
@OneToMany(mappedBy=“部门”)
私人收藏员工;
}

我确信如果你真的读了JPA,搜索了OneToOne关系,你可能会找到一些东西我确信如果你真的读了JPA,搜索了OneToOne关系,你可能会找到一些东西X dic19,我想这是我想要的解决方案。Thx dic19,我想这是我想要的解决方案。