Introduction to Database Indra Budi [email protected] CS - UI.
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Transcript of Introduction to Database Indra Budi [email protected] CS - UI.
Database I – Introduction to Database
Why Use A Database ?
Redundancy (duplication of data)• wasteful of space (storage)• update inefficiencies
(when a dept’s name change, the "record" must be changed each place it is stored)
• data inconsistency (simple keying mistake in the dept name, accidentally have a IS as well as CS, users will wonder whether we have new dept or it’s a mistake) we chose dept from existing dept
Database I – Introduction to Database
List of Teacher Salary & BonusName Address Phone
OfficeSalary Bonus Dept.
Sill, Bill 1 Apple Rd.
07145 $54,613 $27,502 CS
Lan, Jackie
18 Lord Rd.
07122 $46,215 $28,102 Politics
James, Hal
17 Main Street
07122 $48,112 $24,016 Politics
Lan, Hennie
20 Lord Rd.
07145 $44,000 $22,032 CS
Gold, Amy
21 Dear Lane
07122 $42,465 $26,217 Politics
Doe, John
4 High Street
07102 $40,810 $25,419 Economics
Database I – Introduction to Database
The Main Purpose of Database
Database I – Introduction to Database
Applications of databases
• Banks
• Hospital
• Library
• Supermarket
• Magazine & newspaper subscriptions
Database I – Introduction to Database
Extensions
• Multimedia databases
• Geographic Information Systems
• Data warehouse
• On-line analytical processing (OLAP)
• Active & real-time databases
Database I – Introduction to Database
Definition
• Collection of related data which has meaning
• What is data ?• Known facts that can be recorded and that have
implicit meaning• Examples: names, phone number, address the
people
• Those data can be recorded using Ms-Access, Excel, Dbase, etc.
Database I – Introduction to Database
Properties
• Represents some aspect of the real world, called miniworld or Universe of Discourse
• Logically coherent collection of data with some inherent meaning
• Designed, built and populated for specific purpose
Database I – Introduction to Database
More Properties
• Small database: phonebook on your handphones!
• Large & complex database: tax office database
• Why is it much more complex?• The database may be generated and maintain
manually or computerized • Manually ?• Computerized ?
Database I – Introduction to Database
DBMS
Database Management System is a collection of softwares that facilitates the process of • defining,
• constructing and
• manipulating
database for various applications
Database I – Introduction to Database
Database System Environment
Database I – Introduction to Database
Component of A Database System
Database I – Introduction to Database
‘University’ database example
• Has 5 files (‘tables’): • Student
• Course
• Section
• Grade Report
• Prerequisite
• See how do they relate to each other!
• How do we define, construct & manipulate?
Database I – Introduction to Database
Database I – Introduction to Database
Characteristic of Database Approach
• Self describing nature
• Insulation between program and data
• Support of multiple views of data
• Sharing of data & multiuser transaction processing
Database I – Introduction to Database
Self describing nature
• As oppose to unstructured data
• Meta-data describes the structure of the database
• In traditional file processing, data definition is part of the application program
Database I – Introduction to Database
Insulation between programs & data
• Changes to the data structure does not generally require changing the program
• For example, adding a new field ‘Birthday’• The ‘data structure’ is not in the program• We call this program-data independence• DBMS provides conceptual representation• User or programmer does not need to know
how the DBMS store the data in the disk / file.
Database I – Introduction to Database
Multiple Views
Database I – Introduction to Database
Sharing & Multiuser
• DBMS provides concurrency control to ensure ‘correct’ behavior when multiple users update the same database
• Example: airline seat reservation
• It is called On-Line Transaction Processing (OLTP)
Database I – Introduction to Database
The Actors
• Database administrator• Authorizing access rights
• Database designers• Defines the structure of data to be stored
• End users:• Sophisticated non-programmer users
• Naïve users
• Application programmers
Database I – Introduction to Database
Advantages of Using a DBMS
• Controlling redundancy• Restricting unauthorized access• Provides persistent storage for data
structures• Permits inferencing• Multiple user interfaces• Represents complex relations amongst data• Enforcing integrity constraints• Provides backup & recovery
Database I – Introduction to Database
Implications of Database to Organizations
• Could enforce standards
• Reduce application development time
• Flexibility
• Availability of up-to-date information
• Economies of scale
Database I – Introduction to Database
History of Database Processing
Database I – Introduction to Database
Early Database Models
• Before mid-1960s, only sequential file processing using magnetic tape was possible
• In mid-1960s, disk storage enabled hierarchical and network database • IBM’s DL/I (Data Language One)
• CODAYSL’s DBTG (Data Base Task Group) model the basis of current DBMSs
Database I – Introduction to Database
The Relational Model
• E.F. Codd introduced the relational model in 1970
• DB2 from IBM is the first DBMS product based on the relational model
• Other DBMS based on the relational model were developed in the late 1980s
• Today, DB2, Oracle, and SQL Server are the most prominent commercial DBMS products based on the relational model
Database I – Introduction to Database
Personal Computer DBMS
• The advent of microcomputer increases popularity of personal databases
• Graphical User Interface (GUI) make it easy to use• Examples of early DBMS products: dBase,
R:base, and Paradox
Database I – Introduction to Database
Object Oriented DBMS (OODBMS)
• Object-oriented programming started in the mid-1980s
• Goal of OODBMS is to store object-oriented programming objects in a database without having to transform them into relational format
• Object-relational DBMS products, such as Oracle 8i and 9i, allow both relational and object views of data on the same database
• Currently, OODBMS have not been a commercial success due to high cost of relational to object-oriented transformation
Database I – Introduction to Database
Recent History
• Success story of the Microsoft Access • Microsoft Office suite and Windows integration
• Easy-to-use and powerful personal DBMS
• Internet database
• XML and database integration
Database I – Introduction to Database
Library Checkout List
• Sam Archer's card is lost and the card number shown must be replaced, what problem could be occur ?
• If Some Good Fiction is lost and must be removed from the list, what the problem you see will happen ?
• If a new book named Still More Good Fiction is purchased by the library, is it appear in the list ? Why ?
Name Card Number Book Due Date Joe Smith 123-450201 How To Garden 09/12/20xx Sara Jones 123-450217 Some Good Fiction 09/12/20xx Sam Archer 123-450326 How To Build Things 09/15/20xx Sam Archer 123-450326 More Good Fiction 09/15/20xx Joe Smith 123-450201 More How To Garden 09/17/20xx
Database I – Introduction to Database
More Exercise…
• In a database processing system :
1. the database application(s) interact(s) with the DBMS
2. the database application(s) access(es) the database data
3. the DBMS accesses the database data
• Which one is correct ?