Mysql Dumping

Hi Friends,

I am beginner of using Mysql.I need to dump mysql database where the time(hour) is mentioned by user.For Example, user mentioned that time is 1 hr means, we need to dump the data which is stoted before one hour.i used this

?mysqldump -uroot -pmysql dataset1_mh > dataset1_mh_archive1.sql???

?????????in command prompt, actually it is dumped the database withouy any problem but while using inside the code it doesn't dump..

can u please anyone suggest me regarding this ..

Thanks in advance,

Dj