IS 211 Database Systems I

Database Systems I

Grading Policy

• Assessment: 15% coursework, quizzes, and assignments
• 6th week exam: 10%
• 9th week exam: 20%
• Lab coursework: 15%
• Final exam: 40%

Recommended Textbooks

• "Fundamentals of Database Systems" by Ramez Elmasri, 7th edition, 2015

Course Objectives

• Design: model data and structure information in a database
• Programming: use DBMS capabilities
• Balance theoretical foundation with practical database design and implementation

Fundamental Database Concepts

Basic Definitions

• Database: a collection of related data
• Data: known facts with implicit meaning
• Mini-world: a part of the real world about which data is stored in a database
• Database Management System (DBMS): software for defining, constructing, and maintaining a database
• Database System: DBMS software, data, and applications

Types of Databases and Database Applications

• Traditional applications: numeric and textual databases
• More recent applications: multimedia, GIS, biological, genome, data warehouses, mobile databases

Database Application Example

• Phone company (e.g., AT&T) dealing with customer, employee, management, billing, and customer service records

Simplified Database System Environment

• DBMS provides control and coordination to protect data

DBMS Functionality

• Define database structure, data types, and constraints
• Construct or load initial database contents
• Manipulate database: retrieve, modify, and access data
• Process and share data among multiple users and applications

Additional DBMS Functionality

• Provide security measures to prevent unauthorized access
• Perform active processing and take internal actions on data
• Present and visualize data
• Maintain database and associated programs over time

The DBMS Industry

• Major DBMS vendors: Oracle, Microsoft, IBM, Sybase
• Free/Open-source DBMS: MySQL, PostgreSQL, Firebird
• Used by companies such as Google, Yahoo, Lycos, BASF

File Processing Approach vs. Database Approach

• File processing approach: each user defines and implements files for specific applications
• Database approach: single repository maintains data defined once and accessed by various users

Disadvantages of File Processing

• Program-data dependence
• Duplication of data
• Limited data sharing
• Lengthy development times
• Excessive program maintenance

Solution: The Database Approach

• Central repository of shared data
• Data managed by a controlling agent
• Stored in a standardized, convenient form

Characteristics of the Database Approach

• Self-describing nature of a database system
• Insulation between programs and data
• Support of multiple views of the data
• Sharing of data and multiuser transaction processing

Advantages of Using the Database Approach

• Controlling redundancy in data storage and development
• Restricting unauthorized access to data
• Providing efficient query processing and storage structures
• Providing backup and recovery services
• Providing multiple interfaces to different classes of users
• Reduced application development time

When not to use a DBMS

• When the database and applications are simple, well-defined, and not expected to change
• When access to data by multiple users is not required

Database Users

• Database administrators: authorize access, coordinate and monitor use, acquire resources
• Database designers: define database content, structure, and constraints
• End-users: use data for queries, reports, and updates
• System analysts and application developers: understand user requirements, implement specifications, test, and debug

Historical Development of Database Technology

• Early database applications: hierarchical model, network model
• Relational model based systems: introduced in 1970, benefits include accuracy, ease of use, and collaboration