相当于Grails中的InheritanceType.TABLE_PER_CLASS？ [英] equivalent of InheritanceType.TABLE_PER_CLASS in grails?

问题描述

我想为3个域类创建3个单独的表：A，B扩展A，C扩展B
但是我希望他们的表不互相连接。

在hibernate中，我会使用InheritanceType.TABLE_PER_CLASS，在grails中，什么是等效的？

我试图也实现的东西，是的，它可能与Grails，这是一个弯曲勺子一点实现它的情况：

在grails 3下执行此操作

您有一个您希望扩展的基类，并且子表具有相同的字段，即TABLE_PER_CLASS：

我发现另一篇文章有​​帮助，但有一条评论，但现在在这篇文章中正确地扩展和解释它：

这将是我们的基础域类，而不是创建它位于 src / main / groovy / test

之下 grails-app / domains / b
$ b

 包测试
 
 abst ract class Tester {
字符串名称
字符串
 
静态映射= {
 tablePerConcreteClass true 
 id生成器：​​'increment'
 version false 
 
 
  

接下来将

  package test 
 class Tester1 extends Tester> grails-app / domains / test ：
 {
} 
  

和

  package test 
 class Tester2 extends Tester {
} 
  

查看mysql：

  mysql>显示创建表tester2; 
 + --------- + ----------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- ------------------------------ + 
 |表|创建表| 
 + --------- + ----------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- ------------------------------ + 
 | tester2 | CREATE TABLE`tester2`（
`id` bigint（20）NOT NULL，
`something` varchar（255）COLLATE utf8mb4_unicode_ci NOT NULL，
`name`varchar（255）COLLATE utf8mb4_unicode_ci NOT NULL，
 PRIMARY KEY（`id`）
）ENGINE = InnoDB DEFAULT CHARSET = utf8mb4 COLLATE = utf8mb4_unicode_ci | 
 + --------- + ----------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- ------------------------------ + 
 1行（0.00秒）
 
 mysql> show create table tester1; 
 + --------- + ----------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- ------------------------------ + 
 |表|创建表| 
 + --------- + ----------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- ------------------------------ + 
 | tester1 | CREATE TABLE`tester1`（
`id` bigint（20）NOT NULL，
`something` varchar（255）COLLATE utf8mb4_unicode_ci NOT NULL，
`name` varchar（255）COLLATE utf8mb4_unicode_ci NOT NULL，
 PRIMARY KEY（`id`）
）ENGINE = InnoDB DEFAULT CHARSET = utf8mb4 COLLATE = utf8mb4_unicode_ci | 
 + --------- + ----------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- -------------------------------------------------- ------------------------------ + 
 1行（0.00秒）
  

I want to create 3 separate tables for 3 domain classes: A, B extends A, C extends B But I want their tables to be NOT connected to each other.

In hibernate, I would use InheritanceType.TABLE_PER_CLASS, in grails, what would be the equivalent?

解决方案

Something I was trying to also achieve and yes it is possible with grails, it is a case of bending the spoon a little to achieve it:

Doing this under grails 3

You have a base class that you wish to extend and have child tables that have identical fields i.e. TABLE_PER_CLASS:

I found another post that helped and there was a comment but to now expand and explain it correctly on this post:

This would have been our base domain class but instead of creating it in grails-app/domains/ it is created under src/main/groovy/test

package test

abstract class Tester {
    String name
    String something

    static mapping = {
        tablePerConcreteClass true
        id generator: 'increment'
        version false
    }
}

Next out actual domain classes in grails-app/domains/test:

package  test
class Tester1 extends Tester {
}

and

package  test
class Tester2 extends Tester {
}

Looking at mysql:

mysql> show create table tester2;
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table   | Create Table                                                                                                                                                                                                                                                            |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tester2 | CREATE TABLE `tester2` (
  `id` bigint(20) NOT NULL,
  `something` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `name` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> show create table tester1;
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table   | Create Table                                                                                                                                                                                                                                                            |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| tester1 | CREATE TABLE `tester1` (
  `id` bigint(20) NOT NULL,
  `something` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  `name` varchar(255) COLLATE utf8mb4_unicode_ci NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

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