Livelli ta' isolation jikkontrolla kemm jistgħu jraw it-transakzjonijiet konkorrenti l-bidliet uncommitted (jew in-progress) ta' xulxin — jiskambljaw konsistenza kontra prestazzjoni/concurrency. Livelli ta' isolation ogħla jipprevjenu aktar anomaliji imma jżidu l-locking/contention.
L-anomaliji ta' concurrency (dak li l-isolation jipprevjeni)
DIRTY READ → reading another transaction's UNCOMMITTED changes (which may roll back)
NON-REPEATABLE READ → re-reading a row gives different values (another txn UPDATED it)
PHANTOM READ → re-running a query returns different ROWS (another txn INSERTED/DELETED)
