射频识别即RFID（Radio Frequency IDentification）技术，又称无线射频识别，是一种通信技术，可通过无线电讯号识别特定目标并读写相关数据，而无需识别系统与特定目标之间建立机械或光学接触。常用的有低频（125k~134.2K）、高频（13.56Mhz）、超高频，微波等技术。RFID读写器也分移动式的和固定式的，目前RFID技术应用很广，如：图书馆
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.001362s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.092404s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.001233s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001981s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001229s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.003588s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.001066s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003161s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.014785s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001364s ]
UPDATE `jrk_articles` SET `hits` = 1 WHERE `id` = 264121 [ RunTime:0.001332s ]
