hibernate - Grails GORM-在 parent 之前救助 child

Question

我有几个具有子级父级关系的类，但是，当尝试保存所有内容时，Grails GORM首先保存该子级，最终抛出以下错误:

ORA-02291: integrity constraint violated - parent key not found

这是我的类的基本代码表示形式:

class Request
{
  // Mapping definitions
  static mapping = {
    table(name: 'FORMS_REQUEST')
    tablePerHierarchy(false)
    id(length: 20, precision: 20, scale: 0, generator: 'sequence', params: [sequence: 'FORMS_REQUEST_SEQ'])       
  }

  // Properties
  Timestamp version
  Form form
  Date submittedTime
}

abstract class Form
{
  // Mapping definitions
  static mapping = {
    table(name: 'FORMS_FORM')
    tablePerHierarchy(false)
    id(length: 20, precision: 20, scale: 0, generator: 'sequence', params: [sequence: 'FORMS_FORM_SEQ'])
  }

  // Relationship definitions
  static belongsTo = [request: Request]

  // Properties
  Timestamp version
}

class AccessForm extends Form
{
  // Mapping definitions
  static mapping = {
    table(name: 'FORMS_ACCESS_FORM')
    id(length: 20, precision: 20, scale: 0, generator: 'sequence', params: [sequence: 'FORMS_ACCESS_FORM_SEQ'])
  }

  // Relationship definitions
  static hasMany = [adGroups: AccessFormAD, printers: AccessFormPrinter]

  // Properties
  List adGroups
  List printers
}

class AccessFormAD
{
  // Mapping definitions
  static mapping = {
    table(name: 'FORMS_ACCESS_FORM_AD')
    id(length: 20, precision: 20, scale: 0, generator: 'sequence', params: [sequence: 'FORMS_ACCESS_FORM_AD_SEQ'])
  }

  // Relationship definitions
  static belongsTo = [accessForm: AccessForm]

  // Properties
  Timestamp version
}

class AccessFormPrinter
{
  // Mapping definitions
  static mapping = {
    table(name: 'FORMS_ACCESS_FORM_PRINTER')
    id(length: 20, precision: 20, scale: 0, generator: 'sequence', params: [sequence: 'FORMS_ACCESS_FORM_PRINTER_SEQ'])
  }

  // Relationship definitions
  static belongsTo = [accessForm: AccessForm]

  // Properties
  Timestamp version
}

在使用正确的数据等创建所有类之后，调用以下命令:

request.save(flush: true)

我收到上述错误。日志显示了Hibernate编写的以下SQL语句:

Hibernate: select FORMS_REQUEST_SEQ.nextval from dual
Hibernate: select FORMS_FORM_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: select FORMS_ACCESS_FORM_AD_SEQ.nextval from dual
Hibernate: insert into FORMS_ACCESS_FORM_AD (version, checked, DN, type, access_form_id, ad_groups_idx, id) values (?, ?, ?, ?, ?, ?, ?)
Sep. 02 2014 @ 03:58:06 PM - class spi.SqlExceptionHelper - ORA-02291: integrity constraint (FK_954TU4QUPD4QE7H72XGVXSTKV) violated - parent key not found

它首先将子对象保存在 parent 之前，这将解释该错误，但是，我不知道为什么(GORM这样做很愚蠢)，而且我也不知道如何将GORM(休眠)的行为更改为首先保存 parent 。

Answer 1

问题在于，您的Request域类正在对相关的Form使用简单的属性分配。

因此，您需要使用Form form而不是static hasOne = [form:Form]来定义该关系。

原因是GORM通过使用hasOne和hasMany之类的东西来确定关系，进而可以确定需要插入什么顺序。