How To Use Delete Or Upgrade To Delete Data In Rows

if row_id goes from top to bottom and columns go left to right i dont want to delete the row only all data . is it better to use delete or upgrade?

column1|column2|column3
1 items | name1 |name2
2
3
4
5

is there a way to delete name1 and name2 without deleteing any rows?

i have some code ive been tring but it doesnt work.

[code]
publicboolean updatenotdelete(long rowId, String item, String have, String need, String got, String store, String cost) {
ContentValues args = new ContentValues();
// args.put(KEY_ITEMS, item);
args.put(KEY_HAVE, have);

[Code]....