4. I = write(Q), J = write(Q). Since both instructions are write operations, the
order of these instructions does not affect either Ti or Tj . However, the value
obtained by the next read(Q) instruction of S is affected, since the result of
only the latter of the two write instructions is preserved in the database. If
there is no other write(Q) instruction after I and J in S, then the order of I
and J directly affects the final value of Q in the database state that results
from schedule S.