Cannot delete or update a parent row: a foreign key constraint in grails with mysql -

i have subscriber , contact domain , subscriber can have many contacts(one many) in grails app. when try delete data table contact throws error dbcexceptionreporter cannot delete or update parent row: foreign key constraint fails (vprocure5.subscriber_contact, constraintfkc5d3af49e9f29f5foreign key (contact_id) referencescontact(id)).

according error message, can not delete parent row, trying delete contact data children of "subscriber" domain. here subscriber should parent , contact should child domain if not wrong.

subscriber domain

static hasmany= [contacts: contact ] 

contact domain

static belongsto = [subscriber ] 

contactcontroller.grooby

package com.vproc.member  import org.springframework.dao.dataintegrityviolationexception  class contactcontroller {    def springsecurityservice     def subscriberservice   def imageuploadservice   def searchableservice   def autocompleteservice    static allowedmethods = [save: "post", update: "post", delete: "post"]     def index() {     redirect(action: "list", params: params)   }    def list() {      subscriber loggedinsubscriber = subscriber.get( springsecurityservice.principal.id )     list<contact>contactslist = new arraylist<contact>();     loggedinsubscriber?.contacts.each { ->         contactslist.add(it)     }     [contactinstancelist:contactslist , contactinstancetotal: contactslist.size() ]   }    def create() {     [contactinstance: new contact(params)]   }    def save() {      if (params.birthday){         params.birthday = (new simpledateformat("mm/dd/yyyy")).parse(params.birthday)     }     def contactinstance = new contact(params)     subscriber loggedinsubscriber = subscriber.get( springsecurityservice.principal.id )     if (loggedinsubscriber == null)       system.out.println("not able save")      else {       if (!loggedinsubscriber.contacts){         loggedinsubscriber.contacts = new arraylist<contact>();       }       loggedinsubscriber.contacts.add(contactinstance)        if (!loggedinsubscriber.save(flush: true)) {         flash.message = message(code: 'default.created.message', args: [message(code: 'contact.label', default: 'contact'), contactinstance.id])         render(view: "create", model: [contactinstance: contactinstance])         return       }     }      flash.message = message(code: 'default.created.message', args: [message(code: 'contact.label', default: 'contact'), contactinstance.id])     redirect(action: "list")   }      def ajaxdelete = {        def contactinstance = contact.get( params.id );         contactinstance.tags.clear();       println "=========================="       if(contactinstance) {         try {           println "+++++++++++++++++++++++++"           contactinstance.delete(flush:true)            render "contact ${params.id} deleted"          }          catch(org.springframework.dao.dataintegrityviolationexception e) {           render "contact ${params.id} not deleted"         }        }       else {         flash.message = "contact not found id ${params.id}"         render(action:list)       }     } 

contact.groovy

package com.vproc.member  import java.util.date;  import com.vproc.common.tag; import com.vproc.enquiry.contacttype; import grails.converters.json;  class contact {      string name     string phonenumber     string emailaddress     gender gender     string url     string note     byte[] image     string address     date datecreated     date lastupdated     contacttype contacttype     date birthday      static belongsto = [subscriber ]     static hasmany = [tags:tag ,   shares: sharedcontact]     static  constraints = {         image nullable: true         phonenumber nullable: true         url nullable :true         address nullable :true         gender nullable :true         note nullable :true         contacttype nullable :true         birthday nullable :true      }      static mapping = {     tags cascade: "all-delete-orphan" }        //static searchable = [only: ['name', 'emailaddress']]       static searchable = true       static scaffold = true     //static searchable = true } 

subscriber.groovy

package com.vproc.member  import java.util.date;    class subscriber extends partyrole{      transient springsecurityservice      string username     string password     boolean enabled     boolean accountexpired     boolean accountlocked     boolean passwordexpired     statusenum status     date datecreated     date lastupdated     list<contact> contacts ;      static belongsto = [ customer: customer]     static hasmany = [scontacts: contact]        static mapping = {         password column: '`password`'     }      set<role> getauthorities() {         subscriberrole.findallbysubscriber(this).collect { it.role } set     }      def beforeinsert() {         encodepassword()     }      def beforeupdate() {         if (isdirty('password')) {             encodepassword()         }     }      protected void encodepassword() {         password = springsecurityservice.encodepassword(password)     } } 

any idea how can delete contact records here?

delete action in contact controller

def ajaxdelete = {       subscriber loggedinsubscriber = subscriber.get( springsecurityservice.principal.id )       def contactinstance = contact.get( params.id );       contactinstance.tags.clear();       loggedinsubscriber.removefromcontacts(contactinstance)       println "=========================="       if(contactinstance) {         try {           println "+++++++++++++++++++++++++"           contactinstance.delete(flush:true)           render "contact ${params.id} deleted"          }          catch(org.springframework.dao.dataintegrityviolationexception e) {           render "contact ${params.id} not deleted"         }        }       else {         flash.message = "contact not found id ${params.id}"         render(action:list)       }     } 

because you've mapped relationship this:

static belongsto = [subscriber] 

grails has created join table called subscriber_contact. can see in error message:

delete or update parent row: foreign key constraint fails (vprocure5.subscriber_contact, constraintfkc5d3af49e9f29f5foreign key (contact_id) referencescontact(id))

in case, need use removefrom method on subscriber delete contact.

subscriberinstance.removefromcontacts(contactinstance) 

then, gorm internally handle removing row subscriber_contact table.

optionally, should able map relationship using map notation:

static belongsto = [subscriber: subscriber] 

this should negate need grails create join table , should able delete contact directly since contain fk subscriber table.

i created grails app subscriber , contact modeled way have them. wrote following test, passes:

@testfor(contact) @mock([contact, subscriber]) class contacttests {    void setup() {     def subscriber = new subscriber(name: 's1')     def contact = new contact(name: 'c1')     subscriber.addtocontacts(contact)     subscriber.save()   }    void testdeletecontactfromsubscriber() {      assertequals(contact.list().size(), 1)      def dbsubscriber = subscriber.findbyname('s1')     def dbcontact = contact.findbyname('c1')     dbsubscriber.removefromcontacts(dbcontact)     dbcontact.delete()      assertequals(contact.list().size(), 0)   } }