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CS U430: Database Design

Spring 2006Panfeng (Tony) Zhou

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Who am I?

PhD student in Database research area

10 years experiences in DB application development

12 industry world projects in Finance, Education, Health Insurance, Manufacture, etc

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What could you learn from this course?

You will understand the structure of DBMS and DB language (SQL).

You will learn the index methods of database.

You will learn how to implement a web application from scratch.

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Main content of the course

Basic structure of DBMS Queries the database Create/Update table content/structure Design the database (ER model) Web interface for database A project that covers all contents in the

course and you can implement a DBMS from scratch

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Main content of today

1. Introduction to DBMS 2. Relational rules 3. Sample database

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1.1 Database is everywhere

Shop at supermarket (e.g., Stop&Shop, etc).

Shop online (e.g., www.amazon.com).

Borrow book from library. ………..

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1.2 Structure of web DBMS

Webbrowser

Webserver

Databases and DBMS

Structured Query Language(SQL)

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1.3 Products for each components

Component Products

Brower IE, Firefox, etc

Web Server MS IIS, Apache, Resin, etc

DB Server Oracle, DB2, MySQL, MS SQL, MS Access, etc

Operating System

MS Window, Linux, Sun Solaris, etc

Programming language

MS ASP, Java, PHP, etc.

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1.4 What inside the database? A set of tables. Each table “is” a spread sheet.

Staff_ID F_name L_name Position Gender DOB Salary Branch_ID

SA9 Mary Howe Assistant F 19-Feb-70 9000 B007

SG14 David Ford Supervisor M 24-Mar-58 18000 B003

SG37 Ann Beech Assistant F 10-Nov-60 12000 B003

SG5 Susan Brand Manager F 3-Jun-40 24000 B003

SL21 John White Manager M 1-Oct-45 30000 B005

SL41 Julie Lee Assistant F 13-Jun-65 9000 B005

Field

RecordHeader

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2. Relational rules for relational database

Rule 1: First Normal Form Rule Rule 2: Access Row by Content Only

Rule Rule 3: The Unique Row Rule Rule 4: Entity integrity Rule

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2.1 First Normal Form Rule

Fields cannot have multi-values attributes or have any internal structures.

Staff_ID Name Position Clients

001 Tony Manager Amanda

002 Robbie AgentSmith

Andrew

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2.1 First Normal Form Rule (cont)

Staff_ID Name Position Clients1

001 Tony Manager Amanda

002

Robbie

Agent

Smith

Clients2

Andrew

Problems:1. Waste space2. Not flexible

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2.1 First Normal Form Rule (cont)

Staff_ID Name Position Staff_ID

001 Tony Manager

002

Robbie

Agent

Smith

Client

Andrew

Amanda001

002002

Employees Clients

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2.2 Access Row by Content Only Rule

Records can only be retrieved by their content (the attribute values in each record).

Implications:1. There is no order on the records (e.g., We cannot ask for the 3rd record in the employee table)

2. We cannot retrieve a “pointer” to a record to retrieve it later.

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2.3 The Unique Row Rule

Two records in a table cannot be identical in all column values at once.

Staff_ID Name Position

001 Tony Manager

002

Robbie

Agent

001 Tony Manager

Note: Keep this row in your mind. You might spend a lot of time and effort to enforce this rule.

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2.3 The Unique Row Rule (cont)

Table Key: a set of attributes K with two properties:

1. K is unique for each record.2. The subset of K is not unique for each

record.Primary Key: is a table key chosen by

the database designer to uniquely identify specific records in the table.

Note: one table has more than one key, but only one primary key.

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2.3 The Unique Row Rule (cont)

Staff_ID Name Position

001 Tony Manager

003

Robbie

Agent

002 Scott Agent

Employee

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2.4 Entity integrity Rule

The primary key cannot be empty

Staff_ID Name Position

001 Tony Manager

003

Robbie

Agent

null Scott Agent

null Scott Agent

Note: 1. Cannot retrieve the record by primary key.2. Cannot distinguish duplicated records.

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3. Sample database

Client

Private Owner

Properties For Rent

Registration

Staff

Viewing

Branch

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3. Sample database (cont)

Client table PrivateOwner table Staff table Branch table PropertyForRent table Registration table Viewing table

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3. Sample database (cont)

Load table structure Load data in table one by one1. Client table2. PrivateOwner table3. Branch table4. Staff table5. PropertyForRent table6. Registration table7. Viewing table