grails - 在删除父行中出现grails外键错误

Question

我有以下情况:

class Receipt {

   BigDecimal totalAmount;
   Date releaseDate;

   @NotNull
   Integer vatPercentage;

   @NotNull
   Integer discount;

   Boolean isPayed;
   Boolean isInvoice;
   Boolean hasStampDuty;

   Integer documentNumber;

   @NotNull
   static belongsTo = [patient:Patient, doctor:Doctor]

   @NotNull
   static hasMany = [healthServices:Receipt_HealthService]


    static constraints = {
        healthServices(blank:  false)
        patient(blank: false)
        totalAmount(blank: false, )
        vatPercentage(blank: false, nullable: false)

    }


}


class HealthService {

   int vat;
   String description;
   BigDecimal price;

   static belongsTo = [healthServiceType:HealthServiceType, doctor:Doctor]

   static constraints = {
      healthServiceType(blank: false)
      vat(size: 11..11)
      description(maxSize: 255)

    }
}  


class Receipt_HealthService {

   Receipt receipt
   HealthService healthService
   int quantity = 1

   static constraints = {
   }
}

我已经手动创建了Receipt_HealthService域类，如 here中所述。
一切正常，但是当我尝试删除Receipt实例时，出现以下错误:

Cannot delete or update a parent row: a foreign key constraint fails
(`my_localdb`.`receipt_health_service`, CONSTRAINT 
`FK96DE98B9D3292D2C` FOREIGN KEY (`receipt_id`) REFERENCES `receipt`(`id`))

为什么会这样？为什么没有自动删除Receipt_HealthService实例？我需要更改什么以允许自动删除和删除错误？

Answer 1

类Receipt_HealthService没有belongsTo，因此Receipt的删除没有级联。参见http://grails.github.io/grails-doc/latest/guide/GORM.html#cascades。

您可以按以下方式更改Receipt_HealthService:

class Receipt_HealthService {
   ...
   static belongsTo = [receipt: Receipt]
}

或尝试显式定义级联行为(请参见 http://grails.github.io/grails-doc/latest/guide/GORM.html#customCascadeBehaviour)。

另一个可能性是在 beforeDelete中添加一个 Receipt，以删除 healthServices中的每个条目。参见 http://grails.github.io/grails-doc/latest/guide/GORM.html#eventsAutoTimestamping

对于最后一个选项，您可以作为示例查看 User中的 UserRole， Role和 Spring Security Plugin类。我没有在线找到示例项目，但是您可以将插件安装在示例项目中，然后运行 grails s2-quickstart来查看 User#beforeDelete的外观(请参阅 https://grails-plugins.github.io/grails-spring-security-core/ref/Scripts/s2-quickstart.html)。