如何将Entity对象保存到带有生成索引的初始化h2表中？

如何解决如何将Entity对象保存到带有生成索引的初始化h2表中？

我有一个带有h2数据库的spring boot项目。表debug从schema.sql初始化：

DROP TABLE IF EXISTS debug;
  
CREATE TABLE debug (
  id BIGINT PRIMARY KEY,dummycol VARCHAR(250) NOT NULL
);

data.sql：

INSERT INTO debug (id,dummycol) VALUES
  (0,'foo'),(1,'ba');

为此，我必须将spring.jpa.hibernate.ddl-auto=none放在application.properties中。根据{{​​3}}，这对于schema.sql是必要的，但是我发现在生成模式时（我假设从带注释的类中），使用诸如create-drop之类的另一个值，加载脚本{{1 }}被忽略，因此启动后表为空。

我定义一个Entity类：

data.sql

然后，我将@Entity @Table(name = "debug") @Data @NoArgsConstructor public class DebugE { @Id //@GeneratedValue(strategy=GenerationType.AUTO) @Column(name="id") private Long id; @Column(name="dummycol") private String dummy; } 子类化：CrudRepository并将实体对象添加到表中

public interface DebugRepository extends CrudRepository<DebugE,Long>

到目前为止，一切正常，但是现在我想@Autowired DebugRepository cr; ... DebugE d = new DebugE(); d.setId(computeFreeId(cr)) d.setDummy("foo1"); cr.save(d); 被自动设置。 为此，我将id添加到类中并注释掉@GeneratedValue，因为我希望框架能够为我做这件事。我对d.setId没有偏好，到目前为止都行不通：
GenerationType，AUTO：

SEQUENCE

o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 90036,SQLState: 90036 o.h.engine.jdbc.spi.SqlExceptionHelper : Sequence "HIBERNATE_SEQUENCE" not found; SQL statement: call next value for hibernate_sequence [90036-200] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.InvalidDataAccessResourceUsageException: could not prepare statement; SQL [call next value for hibernate_sequence]; nested exception is org.hibernate.exception.SQLGrammarException: could not prepare statement] with root cause org.h2.jdbc.JdbcSQLSyntaxErrorException: Sequence "HIBERNATE_SEQUENCE" not found; SQL statement: call next value for hibernate_sequence [90036-200] at org.h2.message.DbException.getJdbcSQLException(DbException.java:576) ~[h2-1.4.200.jar:1.4.200] ：

IDENTITY

o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 23502,SQLState: 23502 o.h.engine.jdbc.spi.SqlExceptionHelper : NULL not allowed for column "ID"; SQL statement: insert into debug (id,dummycol) values (null,?) [23502-200] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement] with root cause org.h2.jdbc.JdbcSQLIntegrityConstraintViolationException: NULL not allowed for column "ID"; SQL statement: insert into debug (id,?) [23502-200] at org.h2.message.DbException.getJdbcSQLException(DbException.java:459) ~[h2-1.4.200.jar:1.4.200] ：

TABLE

基于其他问题的尝试：

• documentation o.hibernate.id.enhanced.TableGenerator : HHH000351: Could not read or init a hi value org.h2.jdbc.JdbcSQLSyntaxErrorException: Table "HIBERNATE_SEQUENCES" not found; SQL statement: select tbl.next_val from hibernate_sequences tbl where tbl.sequence_name=? for update [42102-200] at org.h2.message.DbException.getJdbcSQLException(DbException.java:453) ~[h2-1.4.200.jar:1.4.200] 并将strategy=GenerationType.IDENTITY添加到hibernate.dialect=org.hibernate.dialect.H2Dialect。 发出警告：application.properties，并且错误消息未更改
• https://stackoverflow.com/a/39094773 添加'hibernate.dialect' is an unknown property.
spring.jpa.hibernate.use-new-id-generator-mappings=false，IDENTITY不变。 SEQUENCE的类似错误：

TABLE

• https://stackoverflow.com/a/63775719/3014199
  将org.hibernate.orm.deprecation : HHH90000015: Found use of deprecated [org.hibernate.id.MultipleHiLoPerTableGenerator] table-based id generator; use org.hibernate.id.enhanced.TableGenerator instead. See Hibernate Domain Model Mapping Guide for details. o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 42102,SQLState: 42S02 o.h.engine.jdbc.spi.SqlExceptionHelper : Table "HIBERNATE_SEQUENCES" not found; SQL statement: select sequence_next_hi_value from hibernate_sequences where sequence_name = 'debug' for update [42102-200] 从spring.jpa.hibernate.ddl-auto设置为none是可行的（即生成ID，将行添加到表），但是现在不再从create-drop初始化表。

其他详细信息

data.sql：

application.properties

spring.datasource.url=jdbc:h2:mem:h2db spring.h2.console.enabled=true spring.h2.console.path=/h2 #spring.jpa.hibernate.ddl-auto=none spring.jpa.hibernate.ddl-auto=create-drop spring.datasource.initialization-mode=embedded #hibernate.dialect=org.hibernate.dialect.H2Dialect #spring.jpa.hibernate.use-new-id-generator-mappings=false ：

build.gradle

解决方案

plugins { id 'org.springframework.boot' version '2.3.3.RELEASE' id 'io.spring.dependency-management' version '1.0.10.RELEASE' id 'java' id "io.freefair.lombok" version "5.2.1" } group = 'com.my.project' version = '0.0.1-SNAPSHOT' sourceCompatibility = '11' repositories { mavenCentral() } dependencies { implementation 'org.springframework.boot:spring-boot-starter-web' implementation 'org.springframework.boot:spring-boot-starter-actuator' implementation 'org.springframework.boot:spring-boot-starter-data-jpa' runtimeOnly 'com.h2database:h2' } 在application.properties中
spring.jpa.hibernate.ddl-auto=none在课堂上和 schema.sql中的@GeneratedValue(strategy=GenerationType.IDENTITY)使它起作用。

解决方法

如果要同时使用* sql文件生成ID，则需要在创建表中的id字段中定义auto_increment属性。

由于使用生成策略-Identity时，hibernate认为列是表侧的自动增量。