1.Read Lock(Shared Locked)--protects read access to an object. The read lock allows other transactions read access but not write access to
the locked area of the table
Write Lock(exclusive lock)
Enhanced write lock (exclusive lock without cumulating)
2. Enque is locking,Deque is unlocking,
check this link for example.
http://help.sap.com/saphelp_nw04s/helpdata/en/cf/21eea5446011d189700000e8322d00/content.htm
Bluesky
