一对多关系支持阅读但不插入 [英] One To Many Relationship Supporting Reads but not INSERTS

问题描述

我正在使用Spring Boot(2.1.1版)来创建需要一对多&具有以下要求的两个模型类之间的多对一关系

模型类是

@Entity
@Table(name="ORGANIZATIONS")
public class Organization{

    @Id
    @GeneratedValue
    Private long id;

    @Column(unique=true)
    Private String name;
}

@Entity
@Table(name="DEPARTMENTS")
Public class Department{

   @Id
   @GeneratedValue
   Private long id;

   @Column(unique=true)
   Private String name;


//…

}

要求

1. 两个组织和部门均应由各自独立的rest api创建.
   • 通过POST/organizations api，我们应该能够创建一个组织，而无需在同一api调用中创建部门.实际上，api应该失败，因为我尝试将部门的json元素作为POST/organizations调用的一部分传递.
   • 在致电POST/部门时，我应该能够传递组织ID，以将新创建​​的部门与组织相关联.
2. GET/organizations api调用应将Collection作为组织对象的一部分返回

问题是

1. 如何关联两个模型对象?是否在组织中添加@OneToMany?我将哪些属性传递给@OneToMany?我是否需要在部门另一侧使用类似的@ManyToOne?

2. 我在REST控制器上是否需要任何特殊注意事项?

解决方案

您仅需要@ManyToOne即可将其保留在Department中，但很可能需要@OneToMany在Organization中才能进行GET请求.

在保存部门时，只需确保您需要:

• 从db获取组织
• 在部门对象上设置获取的组织
• 将部门添加到Organization.departments列表中
• 坚持部门

对于错误处理，请返回BAD_REQUEST响应:

return new ResponseEntity<>(HttpStatus.BAD_REQUEST);

I am using spring boot (verson 2.1.1) to create an application that needs to one-to-many & many-to-one relationship between two model classes with below requirements

The model classes are

@Entity
@Table(name="ORGANIZATIONS")
public class Organization{

    @Id
    @GeneratedValue
    Private long id;

    @Column(unique=true)
    Private String name;
}

@Entity
@Table(name="DEPARTMENTS")
Public class Department{

   @Id
   @GeneratedValue
   Private long id;

   @Column(unique=true)
   Private String name;


//…

}

Requirements

1. Both organizations and departments should be created by separate respective rest api's.
   • Through the POST /organizations api we should be able to create an organization without creating departments in the same api call. In fact the api should fail I tried to pass the json element for department as part of the POST /organizations call.
   • When calling POST /departments I should be able to pass the organization id to associate the newly created department with the organization.
2. The GET /organizations api call should return the Collection as part of the organization object

The questions are

1. How do I associate the two model objects ? Do I add @OneToMany in Organization? What attributes do I pass to @OneToMany? Do I need a similar @ManyToOne on the other side - department?

2. Do I need any special considerations on the REST controllers?

解决方案

You will need @ManyToOne for persisting in Department only but you most likely will need @OneToMany in Organization for the GET request.

Just make sure, when saving the Department, that you need to:

• Fetch from db the organization
• Set the fetched organization on the department object
• Add the department to the Organization.departments list
• Persist the department

For the error handling return a BAD_REQUEST response:

return new ResponseEntity<>(HttpStatus.BAD_REQUEST);

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