Workstation Bug Fix

upgrade_model.php

/**
   * Remove duplicate workstations which is identified by workstation_machine_address
	 * 
	 *  @param void
	 *  
	 *  @return void
	 */
	public function remove_duplicate_workstations()
	{
		//query to find the workstation duplicates
		$sql = "SELECT count(*) as NumberofWS,
				ws_machine_id
				FROM `GA_workstation`
				group by ws_machine_id
				having NumberofWS > 1
				order by NumberofWS desc";
		
		//remove duplicates and update job and printer relationships
		$result = $this->user_database->query($sql);
		
		//check the number of duplications is more than 0
		if($result->num_rows()>0)
		{
			//process eache record
			foreach($result->result_array() as $row)
			{
				//get the workstation duplications
				$cql = "SELECT GROUP_CONCAT(ws_id) AS wrks 
							FROM GA_workstation
								WHERE ws_machine_id = '".$row['ws_machine_id']."'";
				
				//get the workstations list
				$duplicate_wrks = $this->user_database->query($cql);
				
				//check the duplicate counts
				if($duplicate_wrks->num_rows()>0)
				{	
					$dups = $duplicate_wrks->row_array();
					
					//get the duplicates
					$wrks = explode(',', $dups['wrks']);
					
					//check the workstations count
					if(count($wrks)>1)
					{
						//get the unique workstations
						$unique = $wrks[0];
						
						//unset the unique value
						unset($wrks[0]);
						
						//update the workstation details in GA_job table
						$update_job = "UPDATE GA_job SET workstation_id = {$unique}
										WHERE workstation_id IN (".implode(',',$wrks).")";
						
						//execute the query
						$this->user_database->query($update_job);
						
						//update the workstation details in GA_printer table
						$update_printer = "UPDATE GA_printer SET workstation_id = {$unique} 
												WHERE workstation_id IN (".implode(',',$wrks).")";						
						 
						//execute the query
						$this->user_database->query($update_printer);
						
						//delete the duplicate workstations
						$delete_workstation = "DELETE FROM GA_workstation 
												WHERE workstation_id IN (".implode(',',$wrks).")
														AND workstation_id !=".$unique;
						//delete the workstations
						$this->user_database->query($delete_workstation);						
					}	
				}
				
				//free the cached result
				$duplicate_wrks->free_result();
				
			}//endforeach
		}
		
		//avoiding memory leakage
		$result->free_result();		
		
		//status true
		$status['status'] = TRUE;
		
		//return status
		return $status;
		
	}