Timestamping,”A method of managing Database concurrency giving transactions a (relative) start time ts(T).T request read(x)- ts(T) < wrt(x) → Fails: x has change since T read it- ts(T) ≥ wrt(x) → Passes we have the latest version of x - then: rts(x) = MAX( rts(x) ts(T) ) biggest version of readT requests wrt(x)- ts(T) < rts(x) → x was read and is now wrong- ts(T) < wrt(x) → our version of x is wrong- Otherwise it passes wrt(x) = ts(T)"