Tallahassee, Florida, 2015 COP4710 Database Systems Midterm Review Fall 2015

Midterm Exam Time: Wednesday 10/15/2014 3:35pm --- 4:50am – Plan your time well Venue: HWC 2400, 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 1

Midterm Exam 15% of your final score Format 1.Short-answer questions: testing for basic concepts Make your answers clear and succinct Example 1: What is the difference between Cartesian product and natural join? Example 2: Given a relation R in 3NF, is R in BCNF? Why? 2.Relational algebra 3.Relational design 4.SQL 2

Midterm Exam What will be covered? – From “introduction” to “SQL-basics” (the end of today’s class) – 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 3

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

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

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

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

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 8

SQL: Let’s Get Hands Dirty What is SQL? Why SQL? – DDL & DML in SQL Select-From-Where – String pattern matching – 3-value logic – How to answer queries using SQL? 9

Break a Leg!