Information Resources Management January 16, 2001

Agenda n Administrivia n Course Overview n Database Management Systems (DBMSs) n Homework #1

Administrivia n Syllabus n Book n Homework n Web Page

Course Calendar n Eleven Homeworks n Approximately one per week n Exams n Midterm 1 - 2/20 n Midterm 2 - 3/20 n Final - TBA n Quizzes n Up to five

Overview – Perspective n Database Design and Implementation n “Business” Perspective n IT professional in an organization

Database Design n Relational Model n Database Modeling n Evaluation Tools n Normalization

Database Implementation n SQL (Structured Query Language) n Dependability, Reliability n Architecture n Distributed Databases

Database Management Systems n Traditional File Processing Systems n Database n Comparison n Database Lifecycles n Database Management System Functions

Traditional File Processing System n Separate Files n Department n Business Function n Independent of Each Other n High Level of Program Dependence n Program contains file structure and location

Example Time Cards Data Entry Trans Master New Master Checks Report Sort by Employee # Sorted by Employee # Update Master

Data Abstraction (Views) n Physical/Internal n Logical/Conceptual n View/External n How data is stored n What is stored n What is used (subset) Traditional file processing prevents this abstraction. Why?

Three Views of Data External (View) Client Customer Programmer Conceptual (Logical) Designer Database Administrator (DBA) Internal (Physical) Database Administrator (DBA) Tech Support

What is Needed n Physical Independence n Logical Independence

Physical Independence n Physical layout and organization of data can be changed without changing either the overall logical structure of the data or the application programs n Examples n Move data location n Move data to faster storage n Change indexing n Add a secondary key

Physical Independence External (View) Conceptual (Logical) Internal (Physical) No Resulting Change Here Change Here

Logical Independence n Non-loss changes to the logical structure can be made without changing application programs or end-user views n Examples n Change format of a field (zip from 5 to 9) n Add a new data field n Add a new table n Divide a table into two

Logical Independence External (View) Conceptual (Logical) Internal (Physical) No Resulting Change Here Change Here Coordinating Change Here

Database n organized collection of logically related data n shared collection of interrelated data designed to meet the informational needs of multiple users n data is independent of program and user views n data is stored with physical and logical independence

Database Management System (DBMS) n Software that facilitates the implementation of the database concept

Comparison (Traditional vs. Database) n Database Advantages/Traditional Disadvantages n program-data dependence n duplication n data sharing n development times n program maintenance – ripple effects n flexibility

Comparison (Traditional vs. Database) n Database Advantages/Traditional Disadvantages n security n data integrity n data as corporate resource

Comparison (Traditional vs. Database) n Traditional Advantages/Database Disadvantages n size n complexity n cost n special hardware n impact of failure n recovery

Comparison (Traditional vs. Database) n Traditional Advantages/Database Disadvantages n additional personnel n conversion costs n organizational conflict

Database Lifecycle 1. Enterprise Modeling 2. Conceptual Data Modeling 3. Logical Database Design 4. Physical Database Design and Creation 5. Database Implementation 6. Database Maintenance

People Involved n Systems analysts & designers n Database analysts & designers n Users n Programmers n Database Administrators (DBAs) n Networking experts n Other technical experts

Database Management System Functions n data storage, retrieval and update n user-accessible catalog n transaction support n concurrency control n recovery services n authorization services n support for data communication

Database Management System Functions n integrity services n types - character, number, etc. n internal validity n services to promote data independence (logical and physical) n utility services

Database Applications n Personal n one user n Workgroup n small team - LAN connected n Department/Division n multiple teams and functions n Enterprise n entire organization

In-Class Exercise n Groups of 4 n Introduce yourself n Identify a possible database of each type n Pick a speaker

In-Class Exercise n Introduce yourself and group members n Give group’s example databases n personal n workgroup n department/division n enterprise

Personal Databases n Benefits n individualized n meet specific needs n purchased package n Drawbacks n limited to no data sharing n replicated data n consolidation - standardization n support

Workgroup Databases n Benefits n meet specific needs n data shared (across group) n customized “views” n Drawbacks n data sharing across groups n replicated data n security n not optimal for individual n DBMS cost & support

Department Databases n Benefits n meet (specific) needs n data shared n Drawbacks n data sharing n replicated data n security n not optimal for individual/group n performance n DBMS cost & development

Enterprise Databases n Benefits n meet needs n data shared n “mineable” n consistent view to customers n Drawbacks n size & complexity n security n cost & support n development n standards & bureaucracy n distribution & ownership

Best Database? n Personal? n Workgroup? n Department? n Enterprise?

Best Database? n Personal? n Workgroup? n Department? n Enterprise? Combination of databases that meets the needs of individuals, teams, departments, and the company

Best Database? n To the individual, it’s a personal database n To the team, it’s a workgroup database n To the department, it’s a department database n To the CEO, it’s an enterprise database n (To the DBA, it’s a headache)

Homework #1 n Data management recommendation n High-level, experience based n “glossy” vendor material n Show n alternatives n strengths/weaknesses of each n well-reasoned explanation