Understand Oracle Table Lock (TM)

 

Summary of Table Locks

SQL Statement	Table Lock Mode	RS	RX	S	SRX	X
SELECT...FROM table...	none	Y	Y	Y	Y	Y
INSERT INTO table ...	RX	Y	Y	N	N	N
UPDATE table ...	RX	Y*	Y*	N	N	N
DELETE FROM table ...	RX	Y*	Y*	N	N	N
SELECT ... FROM table FOR UPDATE OF ...	RX	Y*	Y*	N	N	N
LOCK TABLE table IN ROW SHARE MODE	RS	Y	Y	Y	Y	N
LOCK TABLE table IN ROW EXCLUSIVE MODE	RX	Y	Y	N	N	N
LOCK TABLE table IN SHARE MODE	S	Y	N	Y	N	N
LOCK TABLE table IN SHARE ROW EXCLUSIVE MODE	SRX	Y	N	N	N	N
LOCK TABLE table IN EXCLUSIVE MODE	X	N	N	N	N	N

RS: row share
RX: row exclusive
S: share
SRX: share row exclusive
X: exclusive