如何覆盖Grails GORM中关系的级联删除？ [英] How do I override the cascade delete for a relation in Grails GORM?

问题描述

我在Grails的GORM部分遇到一些问题。在数据库中，我有两个表模板和报表 >。在GORM级别，我有两个Domain类 Template 和 Report ;

  class Template {
 
 static hasMany = [reports：Report] 
 
 ... 
} 
  

和

  
 static belongsTo = [template：Template] 
 
 ... 
} 
  

默认行为似乎是在删除 Template 时删除将被级联，所有报告 s也将被删除。
在数据库级别上，我尝试使报告中的 template_id 列 -table成为 ON DELETE SET NULL 外键，但没有奏效。

是否有一些方法可以覆盖级联删除？

解决 code> static mapping = {
报告级联：'none'
}

为了能够毫无问题的删除 Template ，除了 Report 类也是必须的： / p>

  static constraints = {
 template（nullable：true）
} 
  

I'm having some problems with the GORM part of Grails. I am using Grails 1.3.4, together with H2.

In the database I have two tables template and report. On the GORM-level I have the two Domain classes Template and Report;

class Template {

static hasMany = [reports: Report]

...
}

and

class Report {

static belongsTo = [template: Template]

...
}

Default behaviour seems to be that when a Template is deleted, the deletion will be cascaded so that all Reports that it has will be deleted as well. On the database level I tried to make the template_id-column in the report-table be a ON DELETE SET NULL foreign key , but that didn't work.

Is there some way to override the cascade delete?

解决方案

The following should be added in the Template class:

static mapping = {
  reports cascade: 'none'
}

to be able to delete Templates without problems, this addition to the Report class is also necessary:

static constraints = {
  template(nullable: true)
}

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