bind dlz 这些是什么意思呢

Fjcyz

dlz "Mysql zone" {
                database "mysql
                {host=localhost dbname=cdn ssl=false port=3306 user=root pass=}
                {select zone from dns_records where zone = '$zone$' and view='CU' limit 1}
                {select ttl, type, mx_priority, case when lower(type)='txt' then concat('\"', data, '\"') when lower(type) = 'soa' then concat_ws(' ', data, resp_person, serial, refresh, retry, expire, minimum) else data end as mydata from dns_records where zone = '$zone$' and host = '$record$' and (view = 'CU' or view = 'DF')}
                {}
                {select ttl, type, host, mx_priority, case when lower(type)='txt' then concat('\"', data, '\"') else data end as mydata, resp_person, serial, refresh, retry, expire, minimum from dns_records where zone = '$zone$' and view='CU'}
                {select zone from xfr_table where zone = '$zone$' and client = '$client$' and view='CU' limit 1}
                {update data_count set count = count + 1 where zone ='$zone$' and view='CU'}";
        };
};


谁可以帮忙解释下各条命令的含义.