OneToMany 关系无法用 liquibase 保存在 spring 中

Question

我正在尝试在 spring 中构建一个数据模型，该模型通过 one-to-many 关系向下级联最多 3 个级别，但我无法使其与 liquibase 脚本一起使用。

我正在使用 spring 引导与 Kotlin 和 liquibase 与 PostgreSQL 数据库。

到目前为止我做了什么：

减少代码以仅包含不起作用的部分（见下文）
我尝试了@OneToMany 和@JoinTable 以及@JoinColumn，我也尝试了@ManyToMany 来排除@OneToMany 的问题
我运行没有 liquibase 的相同代码（下面）让 Hibernate/JPA 从模型创建表
这确实有效，所以我从这些表中生成了 liquibase 脚本，但它们看起来和我自己的完全一样（键名除外）
使用这些模型检索数据有效（如果我直接通过 SQL 插入数据）

老实说我不确定，如果问题出在模型、配置或 liquibase 脚本中，所以我只 post 所有这些。我缺少配置吗？我是否正确配置了级联？我的模型 definitions/liquibase 脚本错了吗？

我在保存 parent 时遇到的异常是：

Hibernate: insert into parent (name) values (?)
2021-12-15 23:29:16.797  WARN 14115 --- [    Test worker] o.h.engine.jdbc.spi.SqlExceptionHelper   : SQL Error: 0, SQLState: 23502
2021-12-15 23:29:16.798 ERROR 14115 --- [    Test worker] o.h.engine.jdbc.spi.SqlExceptionHelper   : ERROR: null value in column "id" of relation "parent" violates not-null constraint
  Detail: Failing row contains (null, Test 1).
org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [id" of relation "parent]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement
...
Caused by: org.hibernate.exception.ConstraintViolationException: could not execute statement
...
Caused by: org.postgresql.util.PSQLException: ERROR: null value in column "id" of relation "parent" violates not-null constraint
  Detail: Failing row contains (null, Test 2).

我正在尝试的代码运行:

val parent = Parent(
    id = 0,
    name = "Test 2"
).apply {
    children = mutableSetOf(
        Child(
            id = 0,
            name = "Test 21",
            parent = this
        ).apply {
            grandchildren =
                mutableSetOf(
                    Grandchild(
                        id = 0,
                        name = "Test 211",
                        child = this
                    )
                )
        },
        Child(
            id = 0,
            name = "Test 22",
            parent = this
        )
    )
}

val saveParent: Parent = parentRepository.save(parent)

型号：

@Entity
class Parent(
    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    var id: Long = 0,
    var name: String,
    @OneToMany(mappedBy = "parent", cascade = [CascadeType.ALL])
    var children: MutableSet<Child> = mutableSetOf()
)

@Entity
class Child(
    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    var id: Long = 0,
    var name: String,
    @ManyToOne @JoinColumn(name = "child_id")
    var parent: Parent,
    @OneToMany(mappedBy = "child", cascade = [CascadeType.ALL])
    var grandchildren: MutableSet<Grandchild> = mutableSetOf()
)

@Entity
class Grandchild(
    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    var id: Long = 0,
    var name: String,
    @ManyToOne @JoinColumn(name = "child_id")
    var child: Child
)

application.yml

spring:
  datasource:
    platform: postgres
    url: jdbc:postgresql://localhost:5432/onetomany?ssl=false
    driver-class-name: org.postgresql.Driver
    initialization-mode: always
  jpa:
    database: postgresql
    database-platform: org.hibernate.dialect.PostgreSQLDialect
    generate-ddl: false
    hibernate:
      ddl-auto: none
  liquibase:
    enabled: true
    change-log: classpath:db/master.xml

liquibase 脚本：

<?xml version="1.1" encoding="UTF-8" standalone="no"?>
<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-4.1.xsd">
  <changeSet author="bruce (generated)" id="data-1">
    <createTable tableName="parent">
      <column name="id" type="BIGINT">
        <constraints nullable="false" primaryKey="true" primaryKeyName="PK_PARENT"/>
      </column>
      <column name="name" type="VARCHAR(255)">
        <constraints nullable="false"/>
      </column>
    </createTable>
  </changeSet>
  <changeSet author="bruce (generated)" id="data-2">
    <createTable tableName="child">
      <column name="id" type="BIGINT">
        <constraints nullable="false" primaryKey="true" primaryKeyName="PK_CHILD"/>
      </column>
      <column name="name" type="VARCHAR(255)">
        <constraints nullable="false"/>
      </column>
      <column name="parent_id" type="BIGINT">
        <constraints nullable="false"/>
      </column>
    </createTable>
  </changeSet>
  <changeSet author="bruce (generated)" id="data-3">
    <createTable tableName="grandchild">
      <column name="id" type="BIGINT">
        <constraints nullable="false" primaryKey="true" primaryKeyName="PK_GRANDCHILD"/>
      </column>
      <column name="name" type="VARCHAR(255)">
        <constraints nullable="false"/>
      </column>
      <column name="child_id" type="BIGINT">
        <constraints nullable="false"/>
      </column>
    </createTable>
  </changeSet>
  <changeSet author="bruce (generated)" id="data-6">
    <addForeignKeyConstraint baseColumnNames="parent_id" baseTableName="child" constraintName="FK_CHILD_PARENT"
                             deferrable="false" initiallyDeferred="false" onDelete="RESTRICT" onUpdate="RESTRICT"
                             referencedColumnNames="id" referencedTableName="parent" validate="true"/>
  </changeSet>
  <changeSet author="bruce (generated)" id="data-8">
    <addForeignKeyConstraint baseColumnNames="child_id" baseTableName="grandchild" constraintName="FK_CHILD_GRANDCHILD"
                             deferrable="false" initiallyDeferred="false" onDelete="RESTRICT" onUpdate="RESTRICT"
                             referencedColumnNames="id" referencedTableName="child" validate="true"/>
  </changeSet>
</databaseChangeLog>

Answer 1

@GeneratedValue(strategy = GenerationType.IDENTITY) 通常通过在数据库中指定一个自动递增的默认值来工作，例如 nextval('my_entity_sequence'::regclass)。插入后，数据库将生成标识符。

在Postgres中，有serial/bigserial伪类型来指定自增列（会在内部创建序列以及列默认值），所以DDL可以例如看起来像这样：
create table my_entity ( id bigserial not null, primary key (id) )
https://www.postgresql.org/docs/current/datatype-numeric.html

在您的情况下，liquibase 错过了所有 ID 列的 type/defaults（现在只有“父”- 插入失败，但其他实体的插入也会失败）。

这是一个已知的 liquibase 问题：https://github.com/liquibase/liquibase/issues/1009 - 解决该问题的建议包括在变更集中手动指定 autoIncrement="true"。

OneToMany 关系无法用 liquibase 保存在 spring 中

OneToMany relation cannot be saved in spring with liquibase

spring

hibernate

one-to-many

liquibase

kotlin