Has anyone developed a multi user system using database table row locks to manage the data that users are modifying? Say where someone has requested data in the system and the corresponding rows (in multiple tables) in the database are locked until the user saves the data back down, logs out, times out (30 min inactivity) or moves on to other data?

Does anyone know any of the problems with using a technique like this? Would it scale? How would you approach this problem with multi users?

Or is it a good technique? What are the advantages of it?

Any opinions, ideas, links, info or anything at all would be greatly appreciated.

Thanks