Hibernate H2指定删除表的顺序 [英] Hibernate H2 specify drop table order

问题描述

我有几乎相同的问题，例如此用户.在每个SpringBootTest之后(例如运行mvn测试时)，Hibernate不能删除我的内存中测试数据库的表.所需的行为是ddl-auto=create-drop，但这不起作用.

I have pretty much the same problem like this user. Hibernate can't drop the tables of my in-memory test database after each SpringBootTest (e.g. when running mvn test). The desired behavior would be ddl-auto=create-drop, but this doesn't work.

我认为原因可能是DROP TABLE语句的无效顺序，因此Hibernate尝试删除其他表仍依赖的表.

I think the reason could be an invalid order of the DROP TABLE statements, so that Hibernate tries to delete tables on which other tables still depend on.

我的data.sql脚本仅包含INSERT语句，并且该架构是根据我的实体自动创建的.我尝试将DROP TABLE语句添加到data.sql的顶部，它们全部通过(ddl-auto=create)，因为我可以指定必须删除它们的顺序. 另一方面，我现在也必须在data.sql中指定架构创建..

My data.sql script only contains INSERT statements and the schema is automatically created based on my entities. I tried adding DROP TABLE statements to the top of data.sql and they all pass (ddl-auto=create), because I can specify the order in which they have to be dropped. On the other side, I now have to specify the schema creation in data.sql too..

是否有一种方法可以指定drop语句的顺序，而不必指定架构的创建?还是有人知道最初的问题的解决方案?

Is there a way to specify the order of drop statements while not having to specify the schema creation? Or does anyone know a solution for the initial problem?

我想举一个例子.我有一个User实体，该实体与其他实体(M:N，1:N，1:1)有关系.创建架构后，hibernate会删除所有表，创建它们并添加约束:

I want to give an example. I have an User entity that has relationships to other entities (M:N, 1:N, 1:1). When the schema is created, hibernate drops all tables, creates them and adds constrains:

// first test file:
Hibernate: drop table user if exists
... // drop other tables
Hibernate: create table user (username varchar(255) not null, ... , primary key (username))
... // create other tables
Hibernate: alter table X add constraint FKgi38hy0tsrdm332gdjrc0uhm3 foreign key (username) references user
Hibernate: alter table Y add constraint FK5svpy1b71l4jxni0xylrbbdtv foreign key (username) references user
Hibernate: alter table Z add constraint FK5a8fxbb0ug3eo1lisdrrxbbj foreign key (username) references user

// next test file:
Caused by: org.h2.jdbc.JdbcSQLSyntaxErrorException: Cannot drop "USER" because "FKGI38HY0TSRDM332GDJRC0UHM3, FK5SVPY1B71L4JXNI0XYLRBBDTV, FK5A8FXBB0UG3EO1LISDRRXBBJ" depends on it; SQL statement:
drop table user if exists [90107-200]

此过程在第一个测试文件之后不起作用，因为它违反了约束.这就是为什么我要指定放置顺序的原因.

This process doesn't work after the first test file, because it violates the constrains. This is why I wanted to specify the drop order.

我不在实体上使用CascadeType，这可能会导致问题吗?

I don't use CascadeType on my entities, could that cause the problem?

推荐答案

我终于找到了解决我的问题的方法. 就像我说的那样，错误是由于尝试删除仍依赖于其他表的表而引起的.我以为这可能与缺少CascadeType规范有关，但我无法解决.

I finally found a work around for my problem. As I said, the errors where caused by trying to drop tables on which other tables still depend on. I thought that this could be related to missing CascadeType specifcations, but I couldn't fix it.

然后我找到了此答案，它对我有用.除了我的data.sql文件(所有数据都插入到自动创建的架构中)之外，我现在还有一个drop-tables.sql，在其中可以指定DROP语句的正确顺序.此文件在自动创建模式之前执行，因此解决了我的问题.

Then I found this answer and it works for me. Additional to my data.sql file (where all my data is inserted to the auto-created schema) I now have a drop-tables.sql where I can specify the correct order of DROP statements. This file is executed before the automatic schema creation and therefore solves my problem.

application.properties:

spring.jpa.properties.javax.persistence.schema-generation.database.action=drop-and-create
spring.jpa.properties.javax.persistence.schema-generation.drop-source=script-then-metadata
spring.jpa.properties.javax.persistence.schema-generation.drop-script-source=drop-tables.sql

这篇关于Hibernate H2指定删除表的顺序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！