What will cause deadlock in Oracle?
It may happen
when you try to delete a row in the parent table of which the child table has no indexes on foreign keys. Because in this case the child table will be locked as whole and it increase the chance of deadlock.
When oracle locks some rows, it may also lightly-lock the whole table, for example, to avoid the table’s structure to be modifed.
Lock Escalation is not Lock Promotion. Lock Promotion only happens to other not-so-good happens who choose to promote the lock in order to reduce the number of locks, because locking is expensive for them.