Database Design: Course Overview

Course Objectives  Learn  Basic database concepts and theories.  Basic data modeling principles.  Practice  Database design  Database implementation skills  Understand  How to build database systems Database Design 2

Course Requirements  Grading  Homework Assignments (20%)  Final Project (80%)  Participation (Extra Credit)  Prerequisites  Basic computer skills (e.g., know how to use PC and Web browser)  Technical background is not required. Database Design 3

Course Policy  Students are expected to be active participant in class discussions, where they will ask questions, provide insights, and explore ideas.  This class advocates an open book policy of allowing students to consult textbooks, Internet resources, and classmates when working on assignments to facilitate learning and promote collaboration.  The Honor Code is in effect. With the open book policy, it is especially important to clearly indicate in submitted work any materials used from other sources. Full citation information should be given for such sources. Database Design 4

Course Resources  Homepage   Required Readings  Lecture material and online contents  Supplemental Readings  Databases Demystified by Andrew Oppel, March 2004, McGraw-Hill Databases Demystified  Absolute Beginner's Guide to Databases (1st edition) by John Petersen; 2002, Que Absolute Beginner's Guide to Databases (1st edition)  Access 2007: The Missing Manual by Matthew MacDonald; 2006, Pogue Press Access 2007: The Missing Manual Database Design 5

Database Overview

Database Intro  Data vs. Information Data is a collection of facts. Information is data processed for knowledge.  Changing data into information Organize data so that it can be viewed in a useful form. What form will the derived information take? How will information be extracted? What data to collect, how & why? Requirements Identify context of data Organize Summarize Database Design 7

Data into Information: Identify Context  Data Obama, Barack H Bush, George H W Bush, George W Clinton, William J Carter, James E  Context Living presidents, United States, 2011/1/1 Name (last name, first name middle initial), birthdate (YYYYMMDD) Class Roster, Database System Course, LIS Department, KMU, Spring 2011 Name (last name, first name middle initial), student ID Database Design 8

Data into Information: Organize Data  Identify metadata Course Title:Database System Course Number: Credit Hours:3.0 Class Time:Tuesday :15 a.m. Thursday 10:30 – 11:45 a.m. Semester:Spring 2011 Instructor:Yang, Kiduk DepartmentLibrary and Information Science SchoolKeimyung University  Identify additional data items. Student Status:Undergraduate Senior GPA:3.7 Major:MIS Database Design 9

Data into Information: Summarize  Patterns, Trends & Visualization Database Design 10 45% LIS 15% CS 15% ACCT 10% IST 15% TCOM CS = Computer Science ACCT = Accounting LIS = Library & Information Science TCOM = Telecommunication Enrollment Pie Chart Enrollment over Time

Database Intro  Purpose Store/retrieve/view data efficiently & effectively. Characteristics A collection of organized data related to a particular subject/purpose Structured data, security, control Database management system data storage, processing, retrieval User Interface data entry, search, view/report Database Design 11

Database: Definitions Database is collection of related data and its metadata organized in a structured format for optimized information management Database Management System (DBMS) is a software that enables easy creation, access, and modification of databases for efficient and effective database management Database System is an integrated system of hardware, software, people, procedures, and data that define and regulate the collection, storage, management, and use of data within a database environment Database Design 12

Database Management System Database Design 13 Database Systems: Design, Implementation, & Management: Rob & Coronel - manages interaction between end users and database

Database System Environment Database Design 14 Database Systems: Design, Implementation, & Management: Rob & Coronel  Hardware  Software - OS - DBMS - Applications  People  Procedures  Data

Evolution of Data Models Timeline Database Design s 1970s1980s1990s2000+ File-based Hierarchical Network Relational Object-oriented Web-based Entity-Relationship

Database: Historical Roots Manual File System to keep track of data used tagged file folders in a filing cabinet organized according to expected use e.g. file per customer easy to create, but hard to locate data aggregate/summarize data Computerized File System to accommodate the data growth and information need manual file system structures were duplicated in the computer Data Processing (DP) specialists wrote customized programs to write, delete, update data (i.e. management) extract and present data in various formats (i.e. report) Database Design 16

File System: Example Database Design 17 Database Systems: Design, Implementation, & Management: Rob & Coronel

File System: Weakness Weakness “Islands of data” in scattered file systems. Problems Duplication same data may be stored in multiple files Inconsistency same data may be stored by different names in different format Rigidity requires customized programming to implement any changes cannot do ad-hoc queries Implications Waste of space Data inaccuracies High overhead of data manipulation and maintenance Database Design 18

File System: Problem Case Database Design 19 CUSTOMER fileAGENT fileSALES file A_Name (15 char) Carol Johnson A_Name (20 char) Carol T. Johnson AGENT (20 char) Carol J. Smith - inconsistent field name, field size - inconsistent data values - data duplication

Database System vs. File System Database Design 20 Database Systems: Design, Implementation, & Management: Rob & Coronel

Relational Database  Problems with legacy database systems Required excessive effort to maintain Data manipulation (programs) too dependent on physical file structure Hard to manipulate by end-users No capacity for ad-hoc query (must rely on DB programmers).  Evolution in Data Organization E. F. Codd’s Relational Model proposal Separated the notion of physical representation (machine-view) from logical representation (human-view) Considered ingenious but computationally impractical in 1970 Relational Database Model Dominant database model of today Eliminated pointers and used tables to represent data Tables – flexible logical structure for data representation – a series of row/column intersections – related by sharing common entity characteristic(s) Database Design 21

Relational Database: Example Database Design 22 Provides a logical “human-level” view of the data and associations among groups of data (i.e., tables)

Entity Relationship Model  Peter Chen’s Landmark Paper in 1976 “The Relationship Model: Toward a Unified View of Data” Graphical representation of entities and their relationships  Entity Relationship (ER) Model Based on Entity, Attributes & Relationships Entity is a thing about which data are to be collected and stored – e.g. EMPLOYEE Attributes are characteristics of the entity – e.g. SSN, last name, first name Relationships describe an associations between entities – i.e. 1:M, M:N, 1:1 Complements the relational data model concepts Helps to visualize structure and content of data groups – entity is mapped to a relational table Tool for conceptual data modeling (higher level representation) Represented in an Entity Relationship Diagram (ERD) Formalizes a way to describe relationships between groups of data Database Design 23

E-R Diagram: Chen Model  Entity  represented by a rectangle with its name in capital letters.  Relationships  represented by an active or passive verb inside the diamond that connects the related entities.  Connectivities  i.e., types of relationship  written next to each entity box. Database Design 24 Database Systems: Design, Implementation, & Management: Rob & Coronel

E-R Diagram: Crow’s Foot Model  Entity  represented by a rectangle with its name in capital letters.  Relationships  represented by an active or passive verb that connects the related entities.  Connectivities  indicated by symbols next to entities. 2 vertical lines for 1 “crow’s foot” for M Database Design 25 Database Systems: Design, Implementation, & Management: Rob & Coronel