1. CS4433 Database Systems
Midterm Review

2. Midterm Exam Time: Monday 03/08/2019 1:30pm --- 2:20pm
Plan your time well
Venue: in-class exam
Closed book, closed note, but you can bring a one-page cheat sheet (A4, double side)
Plan your strategy well
No calculators or other electronic devices
Laptops, ipads, smart phones, etc. are prohibited
Any form of cheating on the examination will result in a zero grade, and will be reported to the university

3. Midterm Exam What will be covered?
From “Introduction” to “Relational design”
Materials in both the slides and the textbook
How to do well in the midterm exam?
Review the materials carefully and make sure you understand them
Reexamine the homework and make sure you can work out the solutions independently
Discuss with your peer students
Discuss with the TA and me
Relax 

4. DB: What and Why?
Besides file systems and OS, why bother yet another so-called DBMS?
Schemas & Data
DDL & DML

5. ER Model: Nothing but Drawing
Entities
Attributes
Relationships
One-one, one-many, many-many
Subclasses
Constraints
Keys, referential integrity, etc.
Weak Entity Set: Why & How?

6. Relational Model: A Step Further
Relation Schema
Primary key, Foreign key, Unique, NULL, Default
Translating ER to Relations
Entities
Relationships (many-many, many-one, one-one)
Weak entity set
Subclass

7. Relational Algebra: Let’s Do Math
Operators and operands
Set-based operators: intersection, subtraction, union…
Other basic operators: selection, projection,..
Derived operators: division…
Cartesian product, theta-join, equi-join, natural join
Relational algebra expressions and expression trees
How to answer queries using relational algebra?

8. Relational Design: Design it right
Motivation
Functional dependencies & keys
Armstrong axioms
Closures
Normal forms and decomposition algorithms
BCNF
Lossless or lossy?
3NF
Functional-dependency preserving or not?
Don’t overdo it