public void addAttributes(List<ColumnDetail> attrs) {
		Iterator<ColumnDetail> itr = attrs.iterator();
		boolean isDuplicate = false;
		
		while(itr.hasNext()) {
			ColumnDetail columnToAdd = itr.next();
			
			Iterator<ColumnDetail> attrsItr = attributes.iterator();
			while (attrsItr.hasNext()) {
				ColumnDetail columnDetail = attrsItr.next();
				// get original name of attribute which the foreign key references to
				String columnName = columnDetail.getRefTableToColumn().get(tableName);
				if(columnDetail.getName().equals(columnName)) {
					isDuplicate = true;
					break;
				}
			}
			
			if (!isDuplicate)
				attributes.add(columnToAdd);
		}
	}