Creating a custom hook for a plugin

hi everyone,

my intention is to create a form in a page for example: name,age,email when i submit the form it should insert the information in the dbase ….i have create the form n created the hook. Problem is when enter some information and submit the form it insert information into the dbase, its fine but when i refresh the page the content is again inserting into the dbase….how can i prevent this…

waiting for solution…..