1.
DML Locks
a.
TX Lock
i. Preventing other transactions from updating the same row
ii. Unlike other databases, it’s not costy for Oracle to have many Locks
b.
TM Lock: Preventing others from modifying the table structure while I am updating its data
2.
DDL Locks
a.
Exclusive DDL Lock: When I am DDLing something (create/drop/alter, etc.), you cannot DDL it or DML it.
b.
Share DDL Lock: When I am DDLing somthing lightly(create index, etc.), you cannot DDL it, but you can DML it.
c.
Breakable parse locks: ….
3.
Latch: To protect objects — Whatever, do use "BIND Variables".
4.
Manual Locking: …