You can use anet.dll or any other dll if you use lite-c, i think.
anyway you will need to use a SQL sentence.
About SQL, read the mySQL manual, on the reference you can find UPDATE keyword, used to modify a row on the database.
You can do something like:

UPDATE tablename
SET column5_name= new_value
WHERE row_id BETWEEN 19 AND 29 ;

you should change tablename, column5_name, new_value for your database.
row_id is your primary key on this table, but you can change te condition to anything,
i hope this helps.