在 Spring boot - H2 数据库中创建外键

Question

假设我有两个简单的表要在我的Spring Boot应用程序中实现。这是ER图：这是我的PasswordReset课：@Data@Entitypublic class PasswordReset {@Id @GeneratedValue Long passwordResetID;String eMail;String token;String createdAt;PasswordReset(){}public PasswordReset(String eMail,String token,String createdAt){    this.eMail=eMail;    this.token=token;    this.createdAt=createdAt;}}这是我的User课（部分）：@Data   @Entity   public class User {@Id @GeneratedValue Long UserID;String eMail;String createdAt;String updatedAt;User(){}public User(String eMail,String createdAt,String updatedAt){    this.eMail=eMail;    this.createdAt=createdAt;    this.updatedAt=updatedAt;}}现在我的问题是如何在我的Spring Boot项目中创建外键，如我的 ER 图？这是我的pom.xml：<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-parent</artifactId>    <version>2.1.6.RELEASE</version>    <relativePath/> <!-- lookup parent from repository --></parent><groupId>com.mua</groupId><artifactId>cse616</artifactId><version>0.0.1-SNAPSHOT</version><name>cse616</name><description>Project for CSE-616</description><properties>    <java.version>11</java.version></properties><dependencies>    <dependency>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-data-jpa</artifactId>    </dependency>    <dependency>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-web-services</artifactId>    </dependency>

Answer 1

• mappedBy在父实体（拥有实体）

• CascadeType.PERSIST,CascadeType.ALL根据一个请求保存一个孩子和一个父母（你可以根据需要找到其他的CascadeType）

• @JoinColumn在我们必须加入的列的子实体

User.java

@OneToMany(mappedBy="user",fetch=FetchType.LAZY,cascade = CascadeType.PERSIST)

private List<ResetPassword> resetpassword = new ArrayList<ResetPassword>();

ResetPassword.java

@ManyToOne(fetch = FetchType.LAZY, targetEntity = User.class)

@JoinColumn(name="userId", referencedColumnName = "userId", nullable = false)

private User user;