基于另外两个实体映射的JPA实体映射

Question

基于另外两个实体映射的JPA实体映射

15

不确定是否可能，但正在尝试在下面的实体中基于另外两个实体映射WorkActionClass和WorkflowInstance，将与之相关的WorkflowInstancePlayer player映射。

public class Action implements Serializable {
@Id
private Long action_id;

@ManyToOne
@JoinColumn(name = "work_action_class_id", referencedColumnName = "work_action_class_id")
private WorkActionClass workActionClass;

@ManyToOne
@JoinColumn(name = "workflow_instance_id", referencedColumnName = "workflow_instance_id")
private WorkflowInstance workflowInstance;

UPDATE: How can I map to a WorkflowInstancePlayer player?????
 @ManyToOne
 @JoinColumns( {
        @JoinColumn(name = "workflow_instance_id", referencedColumnName = "workflow_instance_id", insertable = false, updatable = false),
        @JoinColumn(name = "workActionClass.role_class_id", referencedColumnName = "role_class_id", insertable = false, updatable = false)
})
 private WorkflowInstancePlayer player;

workflowInstancePlayer是基于workflow_instance_id和role_class_id派生的，但实际上role_class_id是workActionClass的属性，映射在(workActionClass.role_class_id)之上。

public class WorkflowInstancePlayer implements Serializable {
@Id
private WorkflowInstance workflowInstance;

@Id
private RoleClass roleClass;

@ManyToOne
@JoinColumn(name = "badge", referencedColumnName = "badge")
private Employee employee;

public class WorkActionClass implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "trx_seq")
private Long work_action_class_id;

@ManyToOne
@JoinColumn(name = "role_class_id")
private RoleClass roleClass;

示例数据可能如下：

Action
------
Id = 10
work_action_class_id = 7
workflow_instance_id = 2


WorkActionClass
---------------
Id = 7
role_name = reviewer
role_class_id = 3


WorkflowInstancePlayer
----------------------
workflow_instance_id = 2
role_class_id = 3
badge = 111222

因此，在操作实体中，我将知道工作流实例玩家是具有ID 111222的雇员，而无需在操作表中存储徽章。

更新

根据Vlad的帖子，我进行了调整。

@ManyToOne(fetch=FetchType.LAZY)
   @JoinColumnsOrFormulas({
   @JoinColumnOrFormula(formula=@JoinFormula(value="(SELECT a.role_class_id FROM (Use Table Name not Entity Name here) a WHERE a.work_action_class_id = work_action_class_id)", referencedColumnName="role_class_id")),
   @JoinColumnOrFormula(column = @JoinColumn(name="workflow_instance_id", referencedColumnName="workflow_instance_id"))
})

- jeff

徽章 = 111222 是工作流实例 ID（=2）和角色类别 ID（=3）的某个函数 - 这正确吗？如果不是，那么你是如何得出徽章 = 111222 的呢？ - NickJI

不是真的。这是一个工作流应用程序。员工111222被分配为工作流中的审核人。根据工作流类型，审核人将有许多操作。Oracle序列号为2的角色是工作流实例ID的下一个角色，并且Reviewer Role的role_class_id为3。因此，这三个值将被插入WorkflowInstancePlayer。 - jeff

@NickJI，我重新阅读了你的评论。如果你的意思是“函数”作为“关系”，那么是的。起初我把它看成了“公式”，比如instance_id乘以role_class_id除以...等等。这个关系在WorkflowInstancePlayer表中被定义。 - jeff

要访问“Employee”，您需要从“RoleClass”或“WorkflowInstance”出发，然后通过“一对多”的遍历方式到达“WorkflowInstancePlayerId”。但是，没有任何指示哪个是正确的“WorkflowInstancePlayerId”，因此我认为这种方法可能行不通。 - NickJI

你可以像这样拥有...（请参见下一个评论）@Transient private Employee actionOwnerUser;public Employee getActionOwnerUser() return actionOwnerUser;public void setActionOwnerUser() //您的手动映射代码 actionOwnerUser = //您的手动映射代码 - NickJI

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- Vlad Mihalcea · Accepted Answer

请尝试使用以下映射：

@ManyToOne
@JoinColumn(
    name = "workflow_instance_id", 
    referencedColumnName = "workflow_instance_id",
    insertable = false, 
    updatable = false
)
private WorkflowInstance workflowInstance;

@ManyToOne
@JoinColumnOrFormula(
    formula = @JoinFormula(
            value="(SELECT a.work_action_class_id FROM WorkActionClass a WHERE a.role_class_id = role_class_id)", 
        referencedColumnName = "work_action_class_id"
    )
)
private WorkActionClass workActionClass;

@ManyToOne
@JoinColumns( {
    @JoinColumn(
        name = "workflow_instance_id", 
        referencedColumnName = "workflow_instance_id"),
    @JoinColumn(
        name = "role_class_id", 
        referencedColumnName = "role_class_id")
})
private WorkflowInstancePlayer player;