Update All records in Gridview

I have a number of records displayed in a Gridview. Each record contains a blank field called Code.

I want to have a field on my form, field A, which I can add a number to and there will be a button called updateCode. When I click the button updateCode I want the number in field A to be updated to the field called Code in each record displayed in the GridView.

Anyone know if this can be achieved?