How do i properly code to deal with concurrencies? {I have more questions....}

Hi,
I'm guessing that i should use a datasets handle concurrencies with tables. assume that when the user requests for a record and the BLL sends a dataset (or DataTable called "Customers"). Another user also request the same record thus returns another dataset with the same name "Customers". So therefore theer are two dataset of teh same name. If this is the case if the first user makes changes to a field that should notify the user 2 about the changes... How do i implement his, in my point of view i shoud link the two datasets (of the same type) so each one will sync eachother....
Is this the way to deal with concurrecies......?
TY IN advance