为什么我在启动 springdata rest api 时会出现异常答案

【问题标题】：why do i get an exception starting springdata rest api为什么我在启动 springdata rest api 时会出现异常
【发布时间】：2020-06-29 19:50:15
【问题描述】：

我的基本休息有点问题，crud api。我的应用程序运行良好，但只有当我的模型中没有任何字段是我制作的对象时。我的录像带模型有 Long id、String title 和 Genre 流派，这种流派是有问题的。 Genre 有 Long id、String 标题和 String 描述。不幸的是，我无法在邮递员中使用 Json 发布我的磁带，因为我想按其名称发送流派。所以我想出了我发布 CassetCreator 而不是 Casset 的解决方案。我的 CassetCreator 与 Casset 相同，但类型为 String。所以我发布对象，获取它的属性并按其名称使用 jpa 搜索类型，然后创建我手动保存的 Casset。问题是，当我这样做时，spring boot 突然抛出异常，我无法删除表......因为它依赖于...... 互联网上的任何解决方案都不适合我，所以我想问你。提前致谢。

型号

import java.time.LocalDate;


@Entity
public class VideoCasset {
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Id
    private Long id;
    private String title;
    private LocalDate productionYear;
    @ManyToOne
    private Genre genre;

    public VideoCasset() {
    }

    public VideoCasset(String title, LocalDate productionYear, Genre genre) {
        this.title = title;
        this.productionYear = productionYear;
        this.genre = genre;
    }

    public Genre getGenre() {
        return genre;
    }

    public void setGenre(Genre genre) {
        this.genre = genre;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public LocalDate getProductionYear() {
        return productionYear;
    }

    public void setProductionYear(LocalDate productionYear) {
        this.productionYear = productionYear;
    }
}

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class Genre {
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Id
    public Long id;
    public String title;
    public String description;

    public Genre() {
    }

    public Genre(String title, String description) {
        this.title = title;
        this.description = description;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }
}

我的问题方法

    @PostMapping
    public VideoCasset addCassett(@RequestBody CassetCreator cassetCreator) {
        String title = cassetCreator.getTitle();
        LocalDate data = LocalDate.parse(cassetCreator.getData());
        String genreName = cassetCreator.getGenre();
        Genre genre = genreManager.findByTitle(genreName);
        VideoCasset videoCasset = new VideoCasset(title, data, genre);
        return cassetVideos.save(videoCasset);
    }

还有例外

2020-03-18 17:18:42.869  INFO 2816 --- [           main] pl.hub.cassets.CassetsApplication        : No active profile set, falling back to default profiles: default
2020-03-18 17:18:43.458  INFO 2816 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2020-03-18 17:18:43.509  INFO 2816 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 44ms. Found 2 JPA repository interfaces.
2020-03-18 17:18:43.908  INFO 2816 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8083 (http)
2020-03-18 17:18:43.915  INFO 2816 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2020-03-18 17:18:43.916  INFO 2816 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.31]
2020-03-18 17:18:44.007  INFO 2816 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2020-03-18 17:18:44.007  INFO 2816 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1088 ms
2020-03-18 17:18:44.095  INFO 2816 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2020-03-18 17:18:44.207  INFO 2816 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2020-03-18 17:18:44.212  INFO 2816 --- [           main] o.s.b.a.h2.H2ConsoleAutoConfiguration    : H2 console available at '/h2-console'. Database available at 'jdbc:h2:file:./bazaDanych2'
2020-03-18 17:18:44.379  INFO 2816 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2020-03-18 17:18:44.436  INFO 2816 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.12.Final
2020-03-18 17:18:44.525  INFO 2816 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.0.Final}
2020-03-18 17:18:44.607  INFO 2816 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2020-03-18 17:18:45.066  WARN 2816 --- [           main] o.h.t.s.i.ExceptionHandlerLoggedImpl     : GenerationTarget encountered exception accepting command : Error executing DDL "drop table genre if exists" via JDBC Statement

org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "drop table genre if exists" via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) ~[hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlString(SchemaDropperImpl.java:375) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.applySqlStrings(SchemaDropperImpl.java:359) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.dropFromMetadata(SchemaDropperImpl.java:241) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.performDrop(SchemaDropperImpl.java:154) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:126) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaDropperImpl.doDrop(SchemaDropperImpl.java:112) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:145) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:314) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:468) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1237) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:391) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:378) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1855) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1792) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:595) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1108) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:868) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at pl.hub.cassets.CassetsApplication.main(CassetsApplication.java:11) ~[classes/:na]
Caused by: org.h2.jdbc.JdbcSQLSyntaxErrorException: Nie można skasować "GENRE" ponieważ zależy od "FK95K03D6B117EMKR21KIGQAUKA"
Cannot drop "GENRE" because "FK95K03D6B117EMKR21KIGQAUKA" depends on it; SQL statement:
drop table genre if exists [90107-200]
    at org.h2.message.DbException.getJdbcSQLException(DbException.java:576) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.message.DbException.getJdbcSQLException(DbException.java:429) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.message.DbException.get(DbException.java:205) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.command.ddl.DropTable.prepareDrop(DropTable.java:98) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.command.ddl.DropTable.update(DropTable.java:124) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.command.CommandContainer.update(CommandContainer.java:198) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.command.Command.executeUpdate(Command.java:251) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.jdbc.JdbcStatement.executeInternal(JdbcStatement.java:228) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.jdbc.JdbcStatement.execute(JdbcStatement.java:201) ~[h2-1.4.200.jar:1.4.200]
    at com.zaxxer.hikari.pool.ProxyStatement.execute(ProxyStatement.java:95) ~[HikariCP-3.4.2.jar:na]
    at com.zaxxer.hikari.pool.HikariProxyStatement.execute(HikariProxyStatement.java) ~[HikariCP-3.4.2.jar:na]
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54) ~[hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    ... 34 common frames omitted

2020-03-18 17:18:45.073  WARN 2816 --- [           main] o.h.t.s.i.ExceptionHandlerLoggedImpl     : GenerationTarget encountered exception accepting command : Error executing DDL "create table genre (id bigint generated by default as identity, description varchar(255), title varchar(255), primary key (id))" via JDBC Statement

org.hibernate.tool.schema.spi.CommandAcceptanceException: Error executing DDL "create table genre (id bigint generated by default as identity, description varchar(255), title varchar(255), primary key (id))" via JDBC Statement
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:67) ~[hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlString(SchemaCreatorImpl.java:439) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlStrings(SchemaCreatorImpl.java:423) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.createFromMetadata(SchemaCreatorImpl.java:314) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.performCreation(SchemaCreatorImpl.java:166) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:135) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:121) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:156) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:73) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:314) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:468) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1237) [hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:391) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:378) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) [spring-orm-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1855) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1792) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:595) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) [spring-beans-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1108) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:868) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE]
    at pl.hub.cassets.CassetsApplication.main(CassetsApplication.java:11) ~[classes/:na]
Caused by: org.h2.jdbc.JdbcSQLSyntaxErrorException: Tabela "GENRE" już istnieje
Table "GENRE" already exists; SQL statement:
create table genre (id bigint generated by default as identity, description varchar(255), title varchar(255), primary key (id)) [42101-200]
    at org.h2.message.DbException.getJdbcSQLException(DbException.java:453) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.message.DbException.getJdbcSQLException(DbException.java:429) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.message.DbException.get(DbException.java:205) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.message.DbException.get(DbException.java:181) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.command.ddl.CreateTable.update(CreateTable.java:89) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.command.CommandContainer.update(CommandContainer.java:198) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.command.Command.executeUpdate(Command.java:251) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.jdbc.JdbcStatement.executeInternal(JdbcStatement.java:228) ~[h2-1.4.200.jar:1.4.200]
    at org.h2.jdbc.JdbcStatement.execute(JdbcStatement.java:201) ~[h2-1.4.200.jar:1.4.200]
    at com.zaxxer.hikari.pool.ProxyStatement.execute(ProxyStatement.java:95) ~[HikariCP-3.4.2.jar:na]
    at com.zaxxer.hikari.pool.HikariProxyStatement.execute(HikariProxyStatement.java) ~[HikariCP-3.4.2.jar:na]
    at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:54) ~[hibernate-core-5.4.12.Final.jar:5.4.12.Final]
    ... 34 common frames omitted

2020-03-18 17:18:45.086  INFO 2816 --- [           main] o.h.e.t.j.p.i.JtaPlatformInitiator       : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2020-03-18 17:18:45.092  INFO 2816 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2020-03-18 17:18:45.368  WARN 2816 --- [           main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2020-03-18 17:18:45.480  INFO 2816 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2020-03-18 17:18:45.627  INFO 2816 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8083 (http) with context path ''
2020-03-18 17:18:45.629  INFO 2816 --- [           main] pl.hub.cassets.CassetsApplication        : Started CassetsApplication in 3.12 seconds (JVM running for 3.966)

【问题讨论】：

我的猜测是您已经拥有现有的数据库并且对实体结构进行了一些更改？因此升级它是不成功的？如果可能的话，附上一些日志，当它发生时（启动？）
抱歉，忘记了日志，但我现在上传了
尝试在Genre 上添加字段List<VideoCasset> videoCassets。用@OneToMany 注释它并在该注释上添加CascadeType.REMOVE
不幸的是不起作用：/没有任何改变，我得到了同样的异常

标签： java spring rest spring-data-jpa crud

【解决方案1】：

尝试对整个数据库进行备份，然后将其删除（或在应用程序属性中指向新数据库）

重新创建它，让 hibernate 从头开始创建整个表结构

从日志看来，现有数据的某些先前结构

Cannot drop "GENRE" because "FK95K03D6B117EMKR21KIGQAUKA" depends on it

Hibernate 无法将数据结构升级到新的结构，试图删除一些具有现有链接的表并重新创建它。

【讨论】：

我现在试了一下，指向新的数据库。结果是它工作一次。一切都很好，但是当我重新运行时，我遇到了完全相同的问题
application.properties 中有什么？在 spring.jpa.hibernate.ddl-auto 或 hibernate.hbm2ddl.auto 中？因为看起来你在那里有create-drop，并且每次运行时，hibernates 都会尝试重新创建整个结构。将其设置为update 并检查
server.port=8084 spring.jpa.properties.hibernate.ddl-auto=create-drop spring.datasource.url=jdbc:h2:file:./db11 spring.h2.console.enabled=true spring.h2.console.path=/h2-console 而且我尝试使用更新，没有任何改变
so on clean database with update on second run it stills throws exception ?
是的，但我发现堆栈跟踪有点不同。而不是Cannot drop "GENRE" because "FK95K03D6B117EMKR21KIGQAUKA" depends on it 我得到Cannot drop "GENRE" because "FKGWYBALXJ55SKJKMXQX8V7AGIR, FK95K03D6B117EMKR21KIGQAUKA" depends on it; 我不知道为什么但我不能“生成”下一个流派的依赖，无论我做什么，每次我得到这两个字符链所以我真的不知道它是如何改变的