Editing records

Question

How to fetch particular record from database by giving its id and edit it and update it in database???
steps: button1(edit) -> textbox1(id) -> fetch particular data from database  -> it should display those records in their respective textbox -> edit and update it.
eg:
button(edit), id______, id__1__ it should display as follows
textbox1: 1 textbox2: name textbox3: mark
(editing)
button2(update) and update it in database..
thank u!!!!