Mon, Nov 1, 1999
------------------------

- Return graded midterms

- Discussion of midterm questions

- Back to swapping conflict-free adjacent actions

- Conflict-Serializability is a sufficient condition for Serializability

Wed, Nov 3, 1999
------------------------

- The Effect of Transaction Semantics

- Venn-Diagrams for Schedules, Serial Schedules, Serializable (S), etc.

- Conflict-Equivalency

- Conflict-Serializability

- Example of Conflict-Serializability (CS) Revisited

- Why CS is not necessary for S

- Given a Schedule 
	- how to test for CS?
		- Topological Sort

- Enforcing CS: Locks
	- Assumptions:
		- Consistency of Transactions
		- Legality of Schedules

- Introduce new operations for locking and unlocking
	- l_1(A), u_1(A) etc.

- Examples of the same serializable schedule 
	with different locking patterns
	- which will be attained?

- 2PL : Two-Phase Locking
	- assures conflict-serializability; why?

Fri, Nov 5, 1999
------------------------

- Envelope of 2PL operation

- Other Issues
	- Who inserts the l and u operations?
	- Is 2PL fool-proof? Answer: No! Potential for Deadlock!!
	- Types of Locks, Lock Hierarchy etc.