grails deleted object would be re-saved by cascade error

Question

I have the project as set-up below. I am trying to delete a project, and I get the following:

2010-09-29 11:45:22,902 [http-8080-1] ERROR errors.GrailsExceptionResolver  - deleted object would be re-saved by cascade (remove deleted object from associatio
ns): [Project#204]
org.hibernate.ObjectDeletedException: deleted object would be re-saved by cascade (remove deleted object from associations): [Project#204]
        at ProjectController$_closure6.doCall(ProjectController:50)
        at ProjectController$_closure6.doCall(ProjectController)
        at org.jsecurity.web.servlet.JSecurityFilter.doFilterInternal(JSecurityFilter.java:382)
        at org.jsecurity.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:180)
        at java.lang.Thread.run(Thread.java:619)

Is there any way to get hibernate to tell me which object has the reference back to the Project object that would be re-saved. What is wrong with my project set up that is causing this circular exception?

public class Project implements Comparable
{  
    static belongsTo = [employee:Employee]

    static hasMany = [roles:Role]
    static constraints = {

    }
    static mapping = {
          description type:"text"
          roles lazy:false, cascade:"all,delete-orphan"
          client lazy:false, cascade:"all,delete-orphan"
          employer lazy:false, cascade:"all,delete-orphan"
    }
}


class Employee implements Comparable
{
    static hasMany = [employeeDesiredSkills:EmployeeDesiredSkill,
                      employeeDesiredTools:EmployeeDesiredTool,
                      employeeAreasOfExpertise:EmployeeAreaOfExpertise,
                      projects:Project,
                      education:Education]


    static mapping = {
           employeeDesiredSkills cascade:"all,delete-orphan", lazy:false
           employeeDesiredTools cascade:"all,delete-orphan", lazy:false
           education cascade:"all,delete-orphan", lazy:false
           projects cascade:"all,delete-orphan", lazy:false
    }
}

public class Role implements Comparable
{

    static belongsTo = [project:Project]
    static hasMany = [roleSkills:RoleSkill,roleTools:RoleTool]

    static mapping = {
        duties type:"text"
        roleSkills cascade:"all,delete-orphan", lazy:false
        roleTools cascade:"all,delete-orphan", lazy:false
        locationType cascade:"all,delete-orphan", lazy:false

    }

    static contraints = {
        endDate(nullable: true)
        roleSkills(nullable: true)
        roleTools(nullable: true)
    }
}

class Employer implements Comparable
{
   static mapping = {
       type lazy:false, cascade:"all,delete-orphan"
   }
}

class RoleTool implements Comparable    
{


  static belongsTo = [role:Role, tool:Tool]//not sure this makes sense, but have to leave it or DB breaks
  Tool tool = new Tool(name:"")
    static mapping = {
      tool cascade:"save-update", lazy:false

    }


class RoleSkill implements Comparable   
{

  static belongsTo = [role:Role, skill:Skill]//not sure this makes sense, but have to leave it or DB breaks
    Skill skill = new Skill(name:"")
    static mapping = {
       skill cascade:"save-update", lazy:false

    }
}

class Skill implements Comparable
{
    static hasMany = [roleSkills:RoleSkill, employeeDesiredSkills:EmployeeDesiredSkill]

    static mapping = {
        roleSkills cascade:"all,delete-orphan", lazy:false
        employeeDesiredSkills cascade:"all,delete-orphan", lazy:false

    }

}

class Tool implements Comparable
{

    static hasMany = [roleTools:RoleTool, employeeDesiredTools:EmployeeDesiredTool]

    static mapping = {
        roleTools cascade:"all,delete-orphan", lazy:false
        employeeDesiredTools cascade:"all,delete-orphan", lazy:false

    }
}

Dirac

Answer 1

Infact, the way you have done the mapping projects cascade:"all,delete-orphan" in the Employee class.

You'll just need to do:

def employee = project.employee; 
employee.removeFromProjects(project);

And the project will be deleted as well. For more details, refer to GORM Gotchas By Peter Ledbrook. Its a 3 part series and explains many similar situations

Yeanling

I finally got it working. It is not infact that simple. I think that there is a grails bug if the projects are stored in SortedSet, then it has a hard time doing that remove. I had to make a copy of the the projects, remove the one I wanted to delete, then add them back to employee to get this to work – Dirac

Answer 2

I know it is late but someone may like to find this here: What happens is that Hibernate uses 'dirtyChecking', as explained in GORM Gotchas By Peter Ledbrook.

To make things short: Hibernate, and so Grails will want to save() the employee object at the end of the Hibernate session (in your case at the .delete(flush:true) call) because it detects that the object has been modified (a project has been suppressed). And the employee must have kept a link toward the project, causing Hibernate to feel you will delete() the project to save() it back again.

To workaround this:

 def employee = project.employee; 
 employee.discard(); 
 project.delete(flush:true);

This tell Hibernate not to save() the employeewithout you asking for it.

Honor

Answer 3

if you have cascade for delete setup, like you do, you need to remove the object-to-delete from its parent before deleting it. From your stacktrace in ProcectController around line 50.

Bet

when you say "object to delete from its parent" does that mean that for this examle I need to remove Project from employee, or do I explicitly have to go down the tree removing all objects taht are about to be deleted from their parents? – Dirac

Here is how I was doing the remove from ProjectController: def employee = project.employee; employee.removeFromProjects(project); project.delete(flush:true) – Dirac

Answer 4

It because at the end of transaction, grails and hibernate will be auto save Parent object, and it detected that a Child deleted so it will not allow delete the Object. So we need:

child.parent.discard()
child.delete()

You can refer here. It resolve my issue.

Absolute