LDB in HR

hi friends,

I am having a doubt, why LDB (HR PNP...) is used in HR, and why not Open sql statements for Reports.

what is the difference between LDB and open sql statement, in what way it is benificial ?

if possible any one send me documents how to use LDB in HR ? to this mail id venkee_12345@yahoo.co.in

thank u HR consultants