Not able to save objects in Grails - grails

Question

I am developing one application in grails. I have following kind of mapping. Now I am saving object of DemoD class but its not saving values neither showing me any error while save. I have printed all created object and all looks fine. but still I am now able to save records.
class DemoS {
String firstName
String lastName
Long rollNumber
String address1
String address2
String city
String state
static constraints = {
address2 nullable:true
}
static hasMany = [demoAList: DemoA]
}
class DemoD {
Date date
static hasMany = [demoAList: DemoA]
def beforeInsert = {
date = new Date()
}
}
class DemoA {
Long id
Boolean absent
Boolean halfday
String notes
Date date
static belongsTo = [demoS:DemoS, demoD:DemoD]
static constraints = {
notes nullable: true
}
}
class UploadDataService {
def saveUploadedData(def dataList) {
def i = 0
DemoD ddObj = new DemoD()
//Getting this dataList from excel and now creating object for each row.
dataList?.each{ rowList ->
if(i != 0){
def dsObj = DemoS.get(rowList[0]?.longValue())
DemoA daObj = new DemoA([id:rowList[0]?.longValue(),absent:rowList[1],halfday:rowList[2],notes:rowList[3] ? rowList[3] : ''])
dsObj.addToDemoAList(daObj)
daObj.demoS = dsObj
ddObj.addToDemoAList(daObj)
daObj.demoD = ddObj
}
i++
}
ddObj.save(saveOnError: true)
}
}