CS 330
Lecture 11
- Finish Security (Ch 10):
- discuss REVOKE
- Circular granting of permissions
- How to represent internally the granting of permissions:
digraph.
- Detecting cycles in digraphs:
- internal representation of digraphs using adjacency
lists
- depth-first search (dfs) algorithm - skecth
- using dfs to detect cycles - sketch.
- Very briefly: mandatory access control (10.5, textbook).
- Exam review:
- Ch. 2, Relational Algebra. Keys (candidate, primary, super
key; foreign key). Integrity constraints. Enforcing integrity
constraints.
- Ch. 8, Relational Algebra: select, project, cross product;
set operations on relations. Joins. Division (on take-home).
- Ch.9, SQL. Bassic SELECT. Set operations. Nested
queries. Aggregate operations. Null values.
On the exam, you can express a query using whatever method you
think will work, if I do not specify explicitly that you should
do it in a certain way. E.g. if I say: do it using nested
queries, with IN or EXISTS, then you should design it using these
constructs. In general I will not specify what should be used -
so you will have to figure out whather an aggregate operation is
appropriate or not, for instance.
- Also from Ch. 9, Embedded SQL. I will not ask you to write
embedded SQL code, but I might ask some general questions about:
- Cursors: declare, open, fetch, close
- host variables
- Ch. 10, Security: Views, GRANT and REVOKE. Expect questions
that might need a discussion. If there is any ambiguity in the
question, be prepared to discuss it and offer 1-2 alternate solutions.
- In-class exercise: Ch.8, ex. 8.3 and 8.4, ch. 9, ex 9.2,. 9.3
and 9.4 (won't have time to finish, just get started; discussion
about certain problems, such as: ambiguity in question 7 on
ex. 8.5; difefrence between question 7 and 8; doing question 11
without aggregate operations, in relational algebra: calcutae
first those which are NOT the most expensive, then subtract from
the set of all parts to find the most expensive aprts!! Use
cross-product. Hint: we did a similar example in class - and it
is in your textbook!
- Contingency plan for in-class exam on Thursday, in case
Mountain Day is on Thursday:
- I will be in my office Th morning 9-10:30, for those of you
who still prefer to take the exam at that time.
- Afterwards, I leave the exam in the Bass (Science)
library. You can pick it up whenever you want, do it and return
it after 1:30 hours. Should do it before Wednesday night (Oct
13), before the fist class after Fall break (Th Oct 14).
- The take-home part is handed in at the same
time as the in-class part. Due Th Oct 14, 9:00am (before class).
- Office hours today and tomorrow: please email to schedule an
appointment and get a confirmation of your allocated time slot. I
am available all day, Tu and Wedn, in principle.
- Hw4 graded by the end of today, and will be available in the
crate by my office door.
Ileana Streinu