Oracle locks cheat sheet

SQL Statement	Row locks?	Mode of table lock	Lock Modes Permitted?
			RS	RX	S	SRX	X
SELECT…FROM table…
INSERT INTO table		RX
UPDATE table …		RX
DELETE FROM table …		RX
SELECT … FROM table FOR UPDATE OF …		RS
LOCK TABLE table IN ROW SHARE MODE		RS
LOCK TABLE table IN ROW EXCLUSIVE MODE		RX
LOCK TABLE table IN SHARE MODE		S
LOCK TABLE table IN SHARE ROW EXCLUSIVE MODE		SRX
LOCK TABLE table IN EXCLUSIVE MODE		X

RS: row share

RX: row exclusive

S: share

SRX: share row exclusive

X: exclusive

 a lock.

 A lock, if no conflicting row locks
are held by another transaction.
Otherwise, waits occur.

The source.