rollback of last updated queries in sql server

Question

Hello seniors,

I have two  buttons. On the click of first button i update some rows in sql server table.
but my operation will complete after click on second button.

suppose after clicking on first button my server will close enexpectedly or someone close server directly. 
Is there any option availiable in sql server to rollback my last update query if the server is down enexpectedly.


Please give suggestion.