Grades, Book & Blackboard

IS2511| Database

Grading Grades will be divided as follows:

10 % Homework and Tutorials 10 % Quizzes 20 % First Midterm Exam 20 % Second Midterm Exam 40 % Final Exam

---------------------------------------------------- 100 % Total

Book & Blackboad Text Book

Fundamentals of Database Systems: ElMasri, Navathe 6th Edition Addison Wesley

Blackboard Lectures will be added in blackboard

1. Databases & Database Systems

Chapter 1

Overview

Traditional database applications are part of our daily life Bank transactions Hotel reservations Etc…

Advances in technology led to more sophisticated database systems applications: Multimedia databases Geographic information systems (GIS) Online analytical processing (OLAP) Real-time and active database technology

1.1 Introduction Database: Collection of data

Data: Recorded facts with implicit meaning

Examples: Address Book – Names, Tel. #s, Addresses Students Sheet – Names, Grades Library Cards – Title, Category, Author

1.1 Introduction

Properties of a database: Representation of real world Coherent data with inherit meaning Designed, built, and populated with data for a reason

Database generation and maintenance:1. Manual – Ex. Library Card Catalog

2. Computerized - Ex. Supermarket’s Inventory

Amazon.com is an example of a large commercial database

1.1 Introduction Database Management System (DBMS):

Collection of programs that enables user to create and maintain a database Database Definition: data types, structures,

constraints Database Construction: storing the actual data on

storage medium controlled by the DBMS Database Manipulation: retrieve data, update

database from miniworld, generate reports

1.1 Introduction Database Management System (DBMS):

Database Sharing: allowing multiple users/programs to access to database simultaneously

Database Protection: System protection against SW/HW crashes Security protection against unauthorized access

Database Maintenance: allowing the system to evolve as requirements change over time

Database

System

1.1 Introduction Database System:

1. Database

2. DBMS

StoredDatabaseDefinition

StoredDatabase

DBMS Software

Software to AccessStored Data

Software to ProcessQueries/Programs

Application Programs/Queries

Users/Programmers

1.2 University Example

1.2 University Example

1. Database Definition1. Specify records in each file

2. Specify data elements of each record

3. Specify data type of each data element

2. Database Construction Store data in the different records of the files Records in different files may be related

Relationships between files

1.2 University Example

3. Database Manipulation Querying for specific data

Ex. “Retrieve a list of all courses and grades of Smith” Ex. “List the names of students who took Database course

in the second semester of 2005 and their grades” Ex. “What are the prerequisites of the Database Course?”

Updating the database Ex. “Change the class of Smith to Sophomore” Ex. “Enter a grade of A for Smith in the Database course

for this semester”

1.3 Characteristics of the Database Approach

File-Based Approach Files are implemented as part of programming the

application Ex. Grade Reporting office and Accounting office

keep different students’ files and programs Some data is not available from the other user’s files

Redundancy in definition and storage Wasted storage space Redundant efforts to maintain the data and keep it

consistent and up-to-date

1.3 Characteristics of the Database Approach

Database Approach1. Self-describing nature of a database system

Meta-data

2. Separation between programs, data, and data abstraction

Program-data independence Regardless of changes in DB structure

Program-operation independence Regardless of implementation

3. Support of multiple views of the data4. Sharing of data and multiuser transaction processing

1.4 Actors on the Scene

1. Database Administrators Authorizing access Coordinating and monitoring DB use Security and response time

2. Database Designers Data identification and structure Acquiring DB requirements Specifying, analyzing and integrating views

1.4 Actors on the Scene3. End Users

1. Casual end users Use sophisticated query language, access different info each time

2. Naïve end users Use standard queries, access specific info

3. Sophisticated end users Implement their own DB using DBMS’s facilities

4. Stand-alone users Use ready-made packages to maintain personal DB

4. System Analysts & Application Programmers SAs determine requirements of end users APs implement, test and debug canned transactions

1.5 Workers behind the Scene

1. DBMS system designers and implementers Design and implement DBMS modules and

interfaces as a software package

2. Tool developers Design and implement SW packages that aid in DB

system design and use

3. Operators and maintenance personnel Responsible for running and maintaining the SW

and HW environment for the DB system

1.6 Advantages of Using a DBMS

1. Controlling redundancy2. Restricting unauthorized access3. Providing persistent storage for program objects and

data structures4. Providing storage structures and search techniques

for efficient query processing5. Providing backup and recovery6. Providing multiple user interfaces7. Representing complex relationships among data8. Enforcing integrity constraints9. Permitting inferencing and actions using rules

1.6 Advantages of Using a DBMS

Additional Implications of Using the Database Approach:

1. Potential for enforcing standards2. Reduced application development time3. Flexibility4. Availability of up-to-date information5. Economies of scale

1.7 A Brief History of Database Applications

Early Database Applications: The Hierarchical and Network Models were introduced in mid

1960s and dominated during the seventies. A bulk of the worldwide database processing still occurs using

these models, particularly, the hierarchical model.

Relational Model-Based Systems: Relational model was originally introduced in 1970, was heavily

researched and experimented within IBM Research and several universities.

Relational DBMS Products emerged in the early 1980s.

1.7 A Brief History of Database Applications

Object-oriented and emerging applications: Object-Oriented Database Management Systems (OODBMSs) were

introduced in late 1980s and early 1990s to cater to the need of complex data processing in CAD and other applications. Their use has not taken off much.

Many relational DBMSs have incorporated object database concepts, leading to a new category called object-relational DBMSs (ORDBMSs)

Extended relational systems add further capabilities (e.g. for multimedia data, XML, and other data types)

1.7 A Brief History of Database Applications

Data on the Web and E-commerce Applications: Web contains data in HTML (Hypertext markup language)

with links among pages This has given rise to a new set of applications and E-

commerce is using new standards like XML (eXtended Markup Language)

Script programming languages such as PHP and JavaScript allow generation of dynamic Web pages that are partially generated from a database Also allow database updates through Web pages

1.7 A Brief History of Database Applications

Extending Database Capabilities: New functionality is being added to DBMSs in the following

areas: Scientific Applications XML (eXtensible Markup Language) Image Storage and Management Audio and Video Data Management Data Warehousing and Data Mining Spatial Data Management Time Series and Historical Data Management

The above gives rise to new research and development in incorporating new data types, complex data structures, new operations and storage and indexing schemes in database systems

1.8 When Not to Use a DBMS

The overhead cost of using a DBMS may be due to: High initial investment and possible need for additional

hardware Overhead for providing generality, security, concurrency

control, recovery, and integrity functions

A DBMS may be unnecessary when: The database and applications are simple, well defined, and

not expected to change There are stringent real-time requirements that may not be

met because of DBMS overhead Access to data by multiple users is not required

1.8 When Not to Use a DBMS

A DBMS may be insufficient when: The database system is not able to handle the complexity of

data because of modeling limitations The database users need special operations not supported by

the DBMS

Any Questions?