问题

在尝试删除 app_user_id 列时，我遇到了这个错误。我已经移除了 app_user_id 表的外键关系。但是我不知道为什么只在运行测试用例时出现这个错误。

错误堆栈信息如下：

SEVERE 2/5/20 2:25 PM: liquibase: liquibase/mt-tenant-changelog-postgres.xml: liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil: 变更集 liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil 失败。错误：Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"；SQL 语句：
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]
INFO 2/5/20 2:25 PM: liquibase: liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil: 成功释放变更日志锁
2020-05-02 14:25:30.600  WARN 9187 --- [           main] ationConfigEmbeddedWebApplicationContext : 在初始化上下文过程中遇到异常 - 取消刷新尝试：org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageSource': 注入自动连接的依赖项失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.service.MultiLingualService com.brotech.product.truelocate.config.DatabaseMessageSource.multiLingualService；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualService'：注入自动连接的依赖项失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.repository.MultiLingualRepository com.brotech.product.truelocate.core.service.MultiLingualServiceImpl.multiLingualRepo；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualRepository'：无法创建类型为 [org.springframework.orm.jpa.SharedEntityManagerCreator] 的内部 bean '(inner bean)#3b4f1eb'，而正在设置 bean 属性 'entityManager'；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#3b4f1eb'：在设置构造函数参数时无法解析对 bean 'entityManagerFactory' 的引用；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration'：注入自动连接的依赖项失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource'：通过工厂方法实例化 bean 失败；嵌套异常是 org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]：工厂方法'dataSource'抛出异常；嵌套异常是 liquibase.exception.MigrationFailedException：变更集 liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil 失败：
     原因：liquibase.exception.DatabaseException: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"；SQL 语句：
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]
2020-05-02 14:25:30.607 ERROR 9187 --- [           main] o.s.boot.SpringApplication               : 应用启动失败

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageSource': 注入自动连接的依赖项失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.service.MultiLingualService com.brotech.product.truelocate.config.DatabaseMessageSource.multiLingualService；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualService'：注入自动连接的依赖项失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.repository.MultiLingualRepository com.brotech.product.truelocate.core.service.MultiLingualServiceImpl.multiLingualRepo；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualRepository'：无法创建类型为 [org.springframework.orm.jpa.SharedEntityManagerCreator] 的内部 bean '(inner bean)#3b4f1eb'，而正在设置 bean 属性 'entityManager'；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#3b4f1eb'：在设置构造函数参数时无法解析对 bean 'entityManagerFactory' 的引用；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration'：注入自动连接的依赖项失败；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource；嵌套异常是 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource'：通过工厂方法实例化 bean 失败；嵌套异常是 org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]：工厂方法'dataSource'抛出异常；嵌套异常是 liquibase.exception.MigrationFailedException：变更集 liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil 失败：
     原因：liquibase.exception.DatabaseException: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUB

<details>
<summary>英文:</summary>

Getting this error when i tried to delete app_user_id column. I did remove the foreign key relation of app_user_id table. But idk why I am getting this only on running a test case.

stackTrace

SEVERE 2/5/20 2:25 PM: liquibase: liquibase/mt-tenant-changelog-postgres.xml: liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil: Change Set liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil failed. Error: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"; SQL statement:
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]
INFO 2/5/20 2:25 PM: liquibase: liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil: Successfully released change log lock
2020-05-02 14:25:30.600 WARN 9187 --- [ main] ationConfigEmbeddedWebApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageSource': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.service.MultiLingualService com.brotech.product.truelocate.config.DatabaseMessageSource.multiLingualService; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.repository.MultiLingualRepository com.brotech.product.truelocate.core.service.MultiLingualServiceImpl.multiLingualRepo; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualRepository': Cannot create inner bean '(inner bean)#3b4f1eb' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#3b4f1eb': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/brotech/product/truelocate/multitenant/DataSourceConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is liquibase.exception.MigrationFailedException: Migration failed for change set liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil:
Reason: liquibase.exception.DatabaseException: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"; SQL statement:
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]
2020-05-02 14:25:30.607 ERROR 9187 --- [ main] o.s.boot.SpringApplication : Application startup failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageSource': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.service.MultiLingualService com.brotech.product.truelocate.config.DatabaseMessageSource.multiLingualService; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.repository.MultiLingualRepository com.brotech.product.truelocate.core.service.MultiLingualServiceImpl.multiLingualRepo; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualRepository': Cannot create inner bean '(inner bean)#3b4f1eb' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#3b4f1eb': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/brotech/product/truelocate/multitenant/DataSourceConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is liquibase.exception.MigrationFailedException: Migration failed for change set liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil:
Reason: liquibase.exception.DatabaseException: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"; SQL statement:
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]
org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/brotech/product/truelocate/multitenant/DataSourceConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is liquibase.exception.MigrationFailedException: Migration failed for change set liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil:
Reason: liquibase.exception.DatabaseException: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"; SQL statement:
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:573)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331)
... 40 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.repository.MultiLingualRepository com.brotech.product.truelocate.core.service.MultiLingualServiceImpl.multiLingualRepo; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualRepository': Cannot create inner bean '(inner bean)#3b4f1eb' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#3b4f1eb': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/brotech/product/truelocate/multitenant/DataSourceConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is liquibase.exception.MigrationFailedException: Migration failed for change set liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil:
Reason: liquibase.exception.DatabaseException: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"; SQL statement:
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:334)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1192)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1116)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:545)
... 42 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.brotech.product.truelocate.core.repository.MultiLingualRepository com.brotech.product.truelocate.core.service.MultiLingualServiceImpl.multiLingualRepo; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualRepository': Cannot create inner bean '(inner bean)#3b4f1eb' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#3b4f1eb': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/brotech/product/truelocate/multitenant/DataSourceConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is liquibase.exception.MigrationFailedException: Migration failed for change set liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil:
Reason: liquibase.exception.DatabaseException: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"; SQL statement:
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:573)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:331)
... 53 common frames omitted
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'multiLingualRepository': Cannot create inner bean '(inner bean)#3b4f1eb' of type [org.springframework.orm.jpa.SharedEntityManagerCreator] while setting bean property 'entityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#3b4f1eb': Cannot resolve reference to bean 'entityManagerFactory' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private javax.sql.DataSource org.springframework.boot.autoconfigure.orm.jpa.JpaBaseConfiguration.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/brotech/product/truelocate/multitenant/DataSourceConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is liquibase.exception.MigrationFailedException: Migration failed for change set liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil:
Reason: liquibase.exception.DatabaseException: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"; SQL statement:
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]
at
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [com/brotech/product/truelocate/multitenant/DataSourceConfig.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is liquibase.exception.MigrationFailedException: Migration failed for change set liquibase/versions/8.0/mt-tenant-schema-and-data-8.0.xml::TREX-263-drop-column-user-related-fields::Sunil:
Reason: liquibase.exception.DatabaseException: Column may be referenced by "PUBLIC.UQ_DASHBOARD_SUBSCRIPTION_DASHBOARD_COMPONENT_APP_USER_FACILITY"; SQL statement:
ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id [90083-194] [Failed SQL: ALTER TABLE PUBLIC.dashboard_subscription DROP COLUMN app_user_id]

please find the **changeset** below that is very normal syntax:

<dropColumn tableName="dashboard_subscription" columnName="app_user_id" />

</details>


# 答案1
**得分**: 1

有时候外键、索引等会被一些对象关系映射（如Hibernate）或其他数据库用户在您不知情的情况下意外创建，这使得修改数据库模式变得有些棘手。

如果您的 `dropColumn` 变更集因为某个现有外键引用而失败，您可以执行以下步骤：

- 通过某个工具（如DBeaver/PgAdmin等，取决于您的数据库）检查数据库模式，查看是否在要删除的列上存在约束或引用；
- 如果这不起作用，从异常堆栈跟踪中获取阻止列删除的引用名称；
- 创建并执行 `dropForeignKeyConstraint`/`dropIndex`/`dropUniqueConstraint` 等变更集；
- 如果该变更集因为其他引用而失败，那么也要删除该引用；
- 最终您将能够删除所需的列；

<details>
<summary>英文:</summary>

Sometimes foreignKeys, indexes, etc. are being created accidentally by some ORM (like Hibernate) or by another database user without you knowing, which makes altering your DB schema a bit tricky.

If your `dropColumn` changeSet is failing because of some existing foreign key reference on it, you can do the following steps:

- check your database schema via some tool like (DBeaver/PgAdmin/etc, depending on your database) for any constraints or references on the column you want to drop;
- if it doesn&#39;t help, get the reference&#39;s name that blocks the column drop from exception stack trace;
- create and execute `dropForeignKeyConstraint`/`dropIndex`/`dropUniqueConstraint`/etc. changeSet;
- if that changeSet fails because of some other reference, then drop that reference as well;
- and at the end you&#39;ll be able to drop the column you want;

</details>