Introduction to Database Systems 1

Introduction to Database

• Prepared by: Mr. Yousif Sufyan

Outline

• Types of Databases and Database Applications

• Basic Definitions

• Typical DBMS Functionality

• Example of a Database (UNIVERSITY)

• Main Characteristics of the Database Approach

• Database Users

• Advantages of Using the Database Approach

• When Not to Use Databases

Types of Databases and Database Applications

Traditional Applications

• Numeric and Textual Databases

More Recent Applications

• Multimedia Databases

• Geographic Information Systems (GIS)

• Data Warehouses

• Real-time and Active Databases

• Diverse other applications

Basic Definitions

• Database: A collection of related data.

• Data: Known facts that can be recorded and have an implicit meaning.

• Mini-world: A portion of the real world about which data is stored (e.g., student grades at a university).

• Database Management System (DBMS): Software for creating and maintaining computerized databases.

• Database System: DBMS software plus the data itself, sometimes including applications.

Simplified Database System Environment

• Components of a database system:

  • Users/Programmers

  • Application Programs/Queries

  • DBMS Software

  • Software to access stored data

  • Stored Database

DBMS Functionality

• Defining Database: Establishing data types, structures, and constraints.

• Constructing or Loading: Initial database content on secondary storage.

• Manipulating Database:

  • Retrieval: Querying, generating reports.

  • Modification: Insertions, deletions, updates.

  • Access through Web applications.

• Processing and Sharing:

  • Handling multiple users and applications while ensuring data validity and consistency.

Other Features of DBMS

• Protection/Security: Prevents unauthorized access.

• Active Processing: Performs internal actions on data.

• Presentation/Visualization of Data.

• Maintenance: Sustaining the database and its applications over time.

Example of a Database (Conceptual Model)

Mini-world for University

Entities

• STUDENTS

• COURSES

• SECTIONS

• DEPARTMENTS

• INSTRUCTORS

Relationships

• SECTIONS belong to COURSES.

• STUDENTS enroll in SECTIONS.

• COURSES have prerequisites.

• INSTRUCTORS teach SECTIONS.

• COURSES are offered by DEPARTMENTS.

• STUDENTS have specific majors in DEPARTMENTS.

Example of a Simple Database

Tables

• COURSE

  Course_name Course_number Credit_hours Department
  Intro to Computer Science	CS1310	4	CS
  Data Structures	CS3320	4	CS
  Discrete Mathematics	MATH2410	3	MATH
  Database	CS3380	3	CS

• SECTION

  Section_identifier Course_number Semester Year Instructor
  85	MATH2410	Fall	04	King
  92	CS1310	Fall	04	Anderson
  102	CS3320	Spring	05	Knuth

• GRADE_REPORT

  Studentnumber Section_identifier Grade
  17	112	B
  17	119	C
  8	85	A

• PREREQUISITE

  Course_number Prerequisite_number
  CS3380	CS3320
  CS3320	CS1310

Main Characteristics of the Database Approach

Self-Describing Nature

• DBMS catalog stores metadata (description of database elements).

• Enables DBMS software to support various database applications.

Program-Data Independence

• Changes in data structures/storage do not require updates to DBMS access programs.

Data Abstraction

• Data models hide storage details, providing a conceptual view for users.

• Programs interact with data model constructs.

Support for Multiple Views

• Different users may see tailored views of the database based on their interests.

Sharing of Data and Multi-user Transaction Processing

• Enables simultaneous data retrieval and updates by concurrent users.

• Concurrency control ensures correct transaction execution.

• Recovery systems maintain transaction integrity.

• OLTP (Online Transaction Processing) allows high-volume concurrent transactions.