Mon, Oct 11, 1999
------------------------

- Corrected mistake made in last class reg. DISTINCT keyword

- More on safety in Datalog queries

- A Mutual Recursion Example

- SQL Subqueries

- SQL aggregation

- SQL ORDER BY clause

- SQL GROUPing, HAVING etc.

Wed, Oct 13, 1999
------------------------

- Calculator button pushing

- Review of PROLOG
	- Animals have four legs 

- PROLOG's Strategy
	- Tuple-at-a-time
	- Backward Chaining
	- Top-Down
	- Goal-Oriented
	- Depth-First

- Typical RDBMS Strategy
	- Set-at-a-time
	- Forward Chaining
	- Bottom-Up
	- Query Optimization

- Detailed PROLOG Example
	
	ancestor(X,Y) <- parent(X,Z), ancestor(Z,Y).
	ancestor(X,X).
	parent(amy,bob).

- Example Query: Who are the ancestors of bob? ancestor(X,bob)?

- What happens if we reverse the order of clauses in the first line?

- entailment in PROLOG (or even first-order logic) is  semi-decidable.

- Commonalities between PROLOG and DBs

	- predicate : relation
	- argument : attribute
	- ground fact : tuple
	- extensional definition : table (with data)
	- intensional definition : view

- Differences between PROLOG and DBs
	- (see above)

- Intersection: Deductive DBMSs
	- Example: CORAL, XSB, LDL, LDL++

- Examples of deductive query optimization tricks

- Same Generation: Hello World of DDBMSs 

- Magic

Fri, Oct 15, 1999
------------------------

- Interfacing DBs with PLs
	- the impedance mismatch problem
	- PL/SQL, Pro*C etc
	- ODBC standards
	- stored procedures
	- cursors as iterators

- Views
	- Relations that are not
	- Example
	- Inserting tuples
	- Updatable Views (NULL <> NULL)
	- Non-updatable Views

- Foreign Keys
	- An implementation of Referential Integrity
	- uses the REFERENCES construct in SQL
	- the REFERENCEd attribute must be the PRIMARY KEY of the other
          relation