def loadFileData(connection, data_file, query_file):
    """(mysql.connection, str, str) -> (int)
       the function loads the data into MySQL DB
       connection: connection to MySQL DB
       data_file: path to data file
       query_file: path to query file
    """    
    # query: load data
    query = readQueryFile(query_file)
    cursor = connection.cursor()      
  
    # execute data loading query
    try:
        cursor.execute( query, {'data_file':data_file} )
    except mysql.connector.Error as err:
        print("Something went wrong: {}".format(err)) 
        # Close cursor
        cursor.close()
        # Close connection
        connection.close()                   
        return -1
    else:
        # Submit transaction
        connection.commit()
        print("File: {}\n is loaded".format(data_file))
        # Close cursor
        cursor.close()       
        # Close connection
        connection.close()   
        return 0