open graph for particular user who is login

Dear Experts,

i designed a dashboard for sales their i had given listbox for employee selection say there are four employess in that listbox e.g

Employee 1: a

Employee 2: b

Employee 3: c

Employee 4: d

say for example if user "a" login in bussiness one he should be able to see only his graph not any one else graph .

tell me solution for this.

Regards

Furqan