Oracle: Difference between locks and latches

Locks are used to protect the data or resourses from the simulteneous use of them by multiple sessions which might set them in inconsistant state… Locks are external mechanism, means user can also set locks on objects by using various oracle statements.

Latches are for the same purpose but works at internal level. Latches are used to Protect and control access to internal data structres like various SGA buffers.They are handled and maintained by oracle and we can’t access or set it.. this is the main difference