protected static function tableDefinition($table_name = "")
{
$table = "\n CREATE TABLE %s (\n region varchar not null,\n state varchar not null,\n time timestamp not null,\n weather varchar not null,\n temperature double,\n uv_index sint64,\n observed boolean not null,\n PRIMARY KEY((region, state, quantum(time, 15, 'm')), region, state, time)\n )";
return sprintf($table, $table_name ? $table_name : static::$table);
}