Below is my code, I want to create Parent Account and Child Account from same group id field i.e.(Pro_Alpha_ID__c - external Id).
Here If Parent account of the perticular group id does not exists then it should create Parent Account with that group id and then its child account.....Currently only child account is created

Please help to solve this


trigger AccountAfterInsertUpdate on Account (after insert) 
{
    Account parentAccObj;  
    List<Account> insertAccMapping = new List<Account>();
    List<Account> updateAccMapping = new List<Account>();
    try{ 
    if(CommonUtility.check){
      CommonUtility.check = false;
       ParentAccObj = [SELECT Id,Name,Pro_Alpha_ID__c FROM Account WHERE RecordTypeId='0129E0000004Ozp' AND Pro_Alpha_ID__c =:trigger.new[0].Pro_Alpha_ID__c];
       Account myAccount=trigger.new[0];
       Account updacc=[select id,Pro_Alpha_ID__c,ParentId from account where id = :myAccount.id];
       system.debug('---------------updacc----->'+updacc);
       system.debug('---------------parentAccObj.Id----->'+parentAccObj.Id);
       updacc.ParentId = parentAccObj.Id;            
       updacc.Pro_Alpha_ID__c = parentAccObj.Pro_Alpha_ID__c;
       update updacc;
      // system.debug('---------------accObj.Pro_Alpha_ID__c----->'+accObj.Pro_Alpha_ID__c);
 //     updateAccMapping.add(updacc);            
   
    }
   }      
    
    catch(Exception e)
    {     
        if(CommonUtility.check){
         CommonUtility.check = false; 
         //create child account first   
         Account childAccount = new Account();         
         childAccount.Name = trigger.new[0].Name;
         childAccount.Phone = trigger.new[0].Phone;
         childAccount.Allgemeine_EMail_Adresse__c = trigger.new[0].Allgemeine_EMail_Adresse__c;
         childAccount.ParentId = trigger.new[0].Id;   
         childAccount.Pro_Alpha_ID__c = trigger.new[0].Pro_Alpha_ID__c;
            system.debug('-------------Exception---------'+e.getMessage());
         //upsert childAccount;  
            
        //create a parent reference
        
        Account parentReference = new Account(Pro_Alpha_ID__c = trigger.new[0].Pro_Alpha_ID__c);
        childAccount.ParentId = parentReference.Id;
            system.debug('----------------childAccount.ParentId--------------'+parentReference.ParentId);
        
       // create parent account now
         Account parentAccount = new Account();         
         parentAccount.Name = trigger.new[0].Name;
         parentAccount.Phone = trigger.new[0].Phone;
         parentAccount.Allgemeine_EMail_Adresse__c = trigger.new[0].Allgemeine_EMail_Adresse__c;
         parentAccount.RecordTypeId = '0129E0000004Ozp';
         parentAccount.Pro_Alpha_ID__c = trigger.new[0].Pro_Alpha_ID__c;
            system.debug('-------------Exception---------'+e.getMessage());
         //upsert parentAccount;  
            
        Database.SaveResult[] results = Database.insert(new SObject[] { parentAccount, childAccount});
        // Check results.
        for (Integer i = 0; i < results.size(); i++) {
        if (results[i].isSuccess()) {
        System.debug('Successfully Created ID: '+ results[i].getId());
        } else {
        System.debug('Error: could not create sobject '+ 'for array element ' + i + '.');
        System.debug(' The error reported was: '+ results[i].getErrors()[0].getMessage() + '\n');
        }
        }
      
    }   
    }     

}