1. Introduction to Database Systems CSE 444
Lecture #1
September,

2. Staff Instructor: Alon Levy TA: Rachel Pottinger
Sieg, Room 310,
Office hours: Wednesday 2:30-3:30
(or by appointment)
TA: Rachel Pottinger
Sieg 226b,
Office hours: Tuesday 2-3, Thursday 1:30 - 2:30 or by appointment

3. Communications Web page: http://www.cs.washington.edu/444/
Mailing list: send to
saying:
subscribe cse444

4. Textbook(s) A First Course in Database Systems Database Implementation
by Jeff Ullman and Jennifer Widom
Database Implementation
by Hector Garcia-Molina, Jeff Ullman and Jennifer Widom
Available in a shrink-wrapped package at the book store (not available in that form for non-students).

5. Other Texts
Database Management Systems (Ramakrishnan) [very comprehensive]
Fundamentals of Database Systems (Elmasri and Navathe) [very widely used]
Foundations of Databases (Abiteboul, Hull and Vianu) [Mostly theory of databases]
Available, on reserve, in the library.

6. Real Business: Why use a DBMS?
Suppose we are building a system to store the information pertaining to the university.
Several questions arise:
how do we store the data? (file organization, etc.)
how do we query the data? (write programs…)
make sure that updates don’t mess things up?
Provide different views on the data? (registrar versus students)
how do we deal with crashes?
Way too complicated! Go buy a database system!

7. Functionality of a DBMS
Storage management
Abstract data model
High level query and data manipulation language
Efficient query processing
Transaction processing
Resiliency: recovery from crashes
Different views of the data, security
Interface with programming languages

8. Building an Application with a Database System
Requirements modeling (conceptual, pictures)
Decide what entities should be part of the application and how they should be linked.
Schema design and implementation
Decide on a set of tables, attributes.
Define the tables in the database system.
Populate database (insert tuples).
Write application programs using the DBMS
way easier now that the data management is taken care of.

9. Conceptual Modeling name category name ssn Takes Course Student
quarter
Advises
Teaches
Professor
name
field
address

10. Schema Design and Implementation
Table Students
Separates the logical view from the physical view of the data.

11. Querying a Database
Find all the students who have taken CSE444 in Fall, 1997.
S(tructured) Q(uery) L(anguage)
select E.name
from Enroll E
where E.course=CS444 and
E.quarter=“Fall, 1997”
Query processor figures out how to answer the query efficiently.

12. Query Optimization Goal: Declarative SQL query
Imperative query execution plan:
Reserves
Sailors
sid=sid
bid=100
rating > 5
sname
(Simple Nested Loops)
SELECT S.sname
FROM Reserves R, Sailors S
WHERE R.sid=S.sid AND
R.bid=100 AND S.rating>5
Plan: Tree of Relational Algebra operators,
with a choice of algorithm implementation for each operator
Ideally: Want to find best plan. Practically: Avoid worst plans!

13. Database Industry
Relational databases are a great success of theoretical ideas.
“Big 3” DBMS companies are among the largest software companies in the world.
IBM (with DB2) and Microsoft (SQL Server, Microsoft Access) are also important players.
$20B industry.
Challenged by object oriented DBMS.

14. The Study of DBMS Several aspects:
Modeling and design of databases
Database programming: querying and update operations
Database implementation
DBMS study cuts across many fields of Computer Science: OS, languages, AI, Logic, multimedia, theory...

15. Course (Rough) Outline
Database design:
Entity Relationship diagrams
ODL (object-oriented design language)
Modeling constraints
The relational model:
Relational algebra
Transforming E/R models to relational schemas

16. Outline (Continued) SQL (“intergalactic dataspeak”)
Views and triggers
Recursive queries and datalog
Object-oriented features
Storage and indexing
Query optimization
Ttransaction processing and recovery
Advanced topics:data integration, XML

17. Structure
Prerequisites: Data structures course (CSE-326 or equivalent).
Work & Grading:
Homework 25%: 6 of them, some light programming.
Project: 30% - see below.
Midterm: 15%
Final: 25%
Intangibles: 5%

18. The Project Goal: design end-to-end database application.
Work in groups of 3-4 (start forming now).
Choose topic on your own.
Some service projects available.
Timetable for project milestones.
Be creative!
Start soon!!