Database Chapter 1

Chapter 1 :

Introduction to Database System

INTRODUCTION TO DATABASE SYSTEM

1.1 Understand Database

Terminologies

Database System Characteristics

Database System Applications

Advantages Database System vs File System

Types of databases

Data Model

Data Model Schema and Data Model Instance

INTRODUCTION TO DATABASE SYSTEM

1.2 Learn Database Language

Data Definition Language (DDL)

Data Manipulation Language (DML)

4G Language (4GL)

1.3 Know Database System Environment

DBMS Component Modules

Database System Utilities

WHY ?????

VS

DATABASE TERMINOLOGIES

* DATA

Facts that have not yet been processed to

reveal their meaning

* INFORMATION

Data that have been processed to reveal

meaning and used for decision making


* DATABASE

A shared, integrated computer

structure that houses a collection of :

* end user data (raw data)

* metadata (data about data, which

the data integrated and managed)


* DBMS

A collection of programs that manages the database

structure and controls access to the data stored in the

database.

* FILED-BASED SYSTEM

A collection of file, folders, each properly tagged and kept

in a filing cabinet. The contents of each file folder were

logically related.


* DATABASE SYSTEM

Organization of components that define and

regulate the collection, storage, management

and use of data within a database

environment.

A SIMPLE FILE SYSTEM

DATABASE SYSTEM CATEGORIES

There is only one database where all

data is stored in one place.

DBMS is placed in a host computer which loads the database.

Examples : supermarkets, libraries

CENTRALIZED

A logical database is distributed to several computers at different locations but working in an integrated manner

Examples : multinational insurance company

DISTRIBUTED

CENTRALIZED DATABASE SYSTEM

DATABASE

SERVER

LIBRARIANS

CATALOGUING SECTION

BORROWINGS /

RETURN SECTION

DB

DB

DB

DB DB

DB SERVER DB SERVER

DISTRIBUTED DATABASE SYSTEM

THE COMPONENTS OF DATABASE SYSTEM

Database System Components

Hardware

Software

People Procedures

Data


Hardware

Refer to all the systems physical devices.

Computer

Computer Peripherals

Computer Network


Software

Collection of programs used by the computers within the

database system. To make the database system function fully, it

takes THREE types of software :

Operating System Software

DBMS Software

Application Programs & Utility S/ware


Operating System S/ware

Examples : DOS, Ms Windows version 95/ 98/ ME/ NT/

2000/ XP, Linux, MacOS, UNIX

DBMS S/ware Examples :

Microsoft Access, Oracle Corporations Oracle and IBMs DB2


Application Programs & Utility S/ware

Application programs commonly used to

access the data found within the database to

generate reports and other information to

facilitate decision making.

Utilities the software tools used to help manage

the database systems computer components

(e.g : GUI Interface to help database administrators

create database structure, control database access

and monitor database operations


People

includes all users of the database system.

PEO

PLE

System Administrator

Database Administrator

Database Designer

System Analyst & Programmer

End Users


Systems Administrators

Oversee the database systems general

operations.

Database Administrators (DBAs)

manage the DBMS use and ensure that the

database is functioning properly.


Database designers

design the database structure (database architects).

System Analyst and Programmers

design and implement the application programs. They

design and create the data entry screens, reports and

procedures.

End Users

the people who use the application programs to run the

organizations daily operations.


Procedures The instructions and rules that govern the design and use of the database system.

Data The collection of facts stored in the database.

THE DATABASE SYSTEM ENVIRONMENT

SUPERMARKET

Universal Code Scanner

Inventory Control System

LIBRARY

Catalog Computer System

UNIVERSITY

Staff Information System

Student Information System

TRAVEL AGENCIES

Ticket Booking System

Hotel Booking System

THE APPLICATION OF DATABASE SYSTEM

DATABASE SYSTEM FILE

Data can be shared by several users

simultaneously

Data can only be used by one user at a time

There are concurrency control software to

allow the process to update data by many

users

Updated files may contain data which is

contrary to the actual data due to update

was not done by the end user

DBMS can control data security from being

used by unauthorized users

Data cannot be controlled by the

unauthorized user because there is no

security controls performed

DBMS facilitate new entry and editing of

data

Waste of space if there are duplicate data

Data can be integrated and centralized

control over standards

THE ADVANTAGES OF A DATABASE APPROACH

COMPARED TO FILE PROCESSING

CONTRASTING DATABASE AND FILE SYSTEM

THE DBMS MANAGES THE INTERACTION

BETWEEN THE END USER AND THE DATA

TYPES OF DATABASES

TYPES OF DATABASES

Personal

A single user database supports only one user at a time.

Workgroup

A multiuser database that supports a relatively

small number of users (usually fewer than 50) or

a specific department within an organization

TYPES OF DATABASES

Enterprise

A database that is used by the entire organization

and supports many users (more than 50, usually

hundreds) across many departments

DATA MODEL / DATABASE MODEL

A data model represents data structures and their

characteristics, relations, constraints and

transformations.

The database designer employs data models as

communications tools to facilitate the interaction

among the designer, the applications programmer

and the end user

The main function to help to understand the complexities of the real world environment

DATA MODEL

DATA MODEL BASIC BUILDING BLOCKS

Relationships Attributes Entities

DATA MODEL

DATA MODEL BASIC BUILDING BLOCKS

Anything, such as a person, place, thing or event about which data are to be collected and stored.

eg : customers, products, flight routes and etc.

Entities

Characteristic of an entity.

eg : a CUSTOMER entity would be described by attributes such as customer last name, customer no id and etc

Attributes

Describes an association among (two or more) entities.

THREE types of relationships :

1:1 (One-to-one) relationship

1:M (one-to-many) relationship

M:N or M:M (many-to-many) relationship

Relationships

DATA MODEL

TYPES OF DATA MODEL

RECORD BASE

OBJECT BASE

PHYSICAL BASE

Relational

Hierarchy

Network

Entity Relationship

Semantic

Functional

Object Oriented

DATA MODEL

First develop by E.F. Codd in 1970.

A simple data structure.

Contribute to the development of database

management system for personal computer

environment such as Microsoft Access,

FoxPro, Paradox and other widely used

HISTORY

RELATIONAL DATABASE MODEL

Model that stores data in tables relationships.

Data and relationships are presented in tables.

Each one has :

Tables complemented with rows & columns Relational

Tuple

Row (Record)

Data types that describe the kind of information found in the column Domain

BASIC STRUCTURE


Term Option 1 Option 2

Relation Table File

Tuple Row Record

Attribute Column Field

Primary Key

Every tuple (record) in the relationship is unique in that

each combination of values for the attribute of each tuple is different. The attribute value is used to identify the key in

particular tuple in relation

TERMINOLOGIES


ID_No name class program

10 DIT 001 Suriati DIT 5 IT

10 DTK 112 Marina DTK 5 TK

10 DIT 006 Shafika DIT 5 IT

10 DTK 118 Iskandar DTK 5 TK

ATTRIBUTE

T

U

P

L

E

Domain :

* ID_No : 10 char

* name : 50 char

* class : 5 char

* program : 3 char


RELATIONAL DATABASE MODEL EXAMPLE

students

RELATIONAL SCHEMA


students

ID_No

name

class

program

course

c_code

c_name

cdt

ID_No

1

= many

The relational name cannot be the same as other relational

name

Each relational cell has only ONE value

Each attribute has a significant name

The value of an attribute is from the same domain

The position of the attribute does not carry any meaning

Each tuple is real and no duplicate tuple

The Null value is used to fill the unknown attribute or does not

exist in a tuple


CHARACTERISTICS


North American Rockwell was the prime

contractor for the Apollo project, which

culminated in a moon landing in 1969.

Such a complex project that required the

management of millions of parts generated by a complex computer file system

However, the file systems can lead to data

redundancy (60%)

HISTORY

HIERARCHY DATABASE MODEL

In the mid 1960s, IBM joined North American Rockwell, replacing the computer tape medium with more up-to-date dick computer storage, which allowed the introduction of complex pointer systems.

The result of the joint Rockwell-IBM effort became known as the information management system (IMS).

The IMS became the worlds leading mainframe hierarchical database system in the 1970s and early 1980s.

HISTORY


BASIC STRUCTURE

The hierarchy database

model is represented by the

upside-down tree known as a

hierarchy structure.


root the top layer (parent of the segment directly beneath it)

segment file systems record type (record)

arch arrow to connect the segment hierarchy path order of sequence

segments tracing the hierarchy structure (left to right)

BASIC STRUCTURE


hierarchy path Eg : Part C Final Assembly Component A Assembly A Part A Part B Component B Component C Assembly B Part C

parent-child relationship (PCR)

Each parent can have many children

Each child has only ONE parent

1:M relationships

BASIC STRUCTURE


HIERARCHY CHARACTERISTICS

The Root record cannot be the kind of child

records in any type of PCR

Each type of record (except the root) must be the

kind of child records in only one type of PCR

If one type of record to be the parent of some types

of PCR, the type of the child records are arranged

and described from left to right in the diagram

hierarchy


DATA STRUCTURE CONCEPT

There are TWO data structure concepts :

Record

- Record is a group of field values that give information

an entity or an event relations

- Each field has a specific data type such as integer, real

and string

Parent-Child Relationship (PCR)

- Involves the relations 1: M between the two types of

records (Parent Record Type and Child Record Type)


HIERARCHY SCHEMA


A database schema that consists

of the hierarchy schemes

Each hierarchy schema consists

of several types of records and

the type of PCR

HIERARCHY SCHEMA DIAGRAM

DEPARTMENT

D_Name D_Code HOD

LECTURER

L_Name IC Address

COURSE

C_Name C_Code Class_Total

STUDENT

S_Name ID_No DOB Age Class


Based on the diagram, PCR can be divided into THREE parts :

Department, Lecturer

Department, Course

Course, Student

Hierarchy Schema involved :

* name of the record type in the box

* PCR type as the arch that connect the parent record to

the child record

HIERARCHY SCHEMA DIAGRAM


DEPARTMENT

D_Name D_Code HOD

LECTURER

L_Name IC Address

COURSE

C_Name C_Code Class_Total

STUDENT

S_Name ID_No DOB Age Class


DATABASE DESCRIPTION (DBD) DEFINITIONS

1. DBD NAME = INSTITUTION

2. SEGM NAME = DEPARTMENT, BYTES = 35

3. FIELD NAME = D_NAME, BYTES = 10, START = 1

4. FIELD NAME = D_CODE, BYTES = 5, START = 11

5. FIELD NAME = HOD, BYTES = 20, START = 16

6. SEGM NAME = LECTURER, PARENT = DEPARTMENT, BYTES = 68

7. FIELD NAME = L_NAME, BYTES = 20, START = 1

8. FIELD NAME = IC, BYTES = 8, START = 21

9. FIELD NAME = ADDRESS, BYTES = 40, START = 29

10. SEGM NAME = COURSE, PARENT = DEPARTMENT, BYTES = 28

11. FIELD NAME = C_NAME, BYTES = 20, START = 1

12. FIELD NAME = C_CODE, BYTES = 5, START = 21

13. FIELD NAME = CLASS_TOTAL, BYTES = 3, START = 26

14. SEGM NAME = STUDENT, PARENT = COURSE, BYTES = 50

15. FIELD NAME = S_NAME, BYTES = 25, START = 1

16. FIELD NAME = ID_NO, BYTES = 10, START = 26

17. FIELD NAME = DOB, BYTES = 8, START = 36

18. FIELD NAME = AGE, BYTES = 2, START = 44

19. FIELD NAME = CLASS, BYTES = 5, START = 46

20. DBGEN

21. FINISH

22. END

DATABASE DESCRIPTION (DBD) DEFINITIONS


LANGUAGES


Language

Hierarchical Data Definition Language (HDDL)

Hierarchical Data Manipulation

Language (HDML)

HDDL

- Intended to show how the hierarchical database schema is generated.

- Needed :

Field for each type of record

Type of data for each field

Determine the type of 'root record is the parent record in the PCR

Virtual Parent Record Child type

HDML

- A Language to manipulate hierarchical database

- The language instruction must be included in the multi-purpose

programming languages

LANGUAGES


One of the Hierarchical system

Is an information system designed to assist the management

of an organization

The system does not have query languages

Application program written in COBOL, FORTRAN and

Basic Assembly Language

INFORMATION MANAGEMENT SYSTEM (IMS)


A database management system and

is used in the transaction (accounts

/ large inventory system)

IMS DEFINITION


Hierarchical system that is stored in the IMS

database known as Physical Database (PDB)

A number of physical database collected for the

storage process

Each physical database has a data definition or a

schema written in DL / 1 (Data Language One)

IMS ARCHITECTURE


DL/1 (Data Language One)

Data Definition and Data Manipulation language in IMS

This data definition known as Database Description- DBD

DBD that has been compiled are stored in internal

storage which includes how the mapping definition

database stored in the storage and information retrieval

methods provided

IMS ARCHITECTURE


APPLICATION PROGRAM

PCB PCB PCB

DBD DBD DBD .

DATABASE STORAGE

ACCESS METHOD

PROGRAM COMMUNICATION BLOCK (PCB)

DATABASE DEFINITIONS

IMS ARCHITECTURE


IMS provides TWO types of view :

View 1

define with PCB By selecting a portion of a physical database (ie: one

subhierarchy) and defined by 'Program Communication Block' (PCB)

View 2

define with logical database By selecting some parts of some physical database and

the relationship of these parts to be a new hierarchy and it is defined in the DL/1

with DBD Logic (Logical Database Definition). The result of the new structure is

called a Logical Database (LDB)

VIEW IN IMS


Solve the hierarchical database model

problems delegate many to many relationship (M: M).

Do not follow the industry standards

Introduced as an improvement to the

hierarchical database model

HISTORY

NETWORK DATABASE MODEL

Consists of several types of

records and linked through

pointers

DEFINITION


SALEREP CUSTOMER

INVOICE PRODUCT PAYMENT

INV_LINE

1:M 1:M 1:M

1:M 1:M

Commition Set Sales Set Payment Set

Line Set Inventory Set



The record in below level known as a member

of the record and can be connected to one or

more parent known as the owner.

This relationship is called a set.

One set shows the relationship one to many

(1: M) between the records.

NETWORK DB DESIGN


SALEREP CUSTOMER

INVOICE PRODUCT PAYMENT

INV_LINE

1:M 1:M 1:M

1:M 1:M

Commition Set Sales Set Payment Set

Line Set Inventory Set

record

Member record

owner

SET

NETWORK DATABASE DESIGN


More flexible because the information can be

obtained through many ways.

Can represent many to many relationships (M: M).

Each owner is not limited to one relationship and

each record can have more than one relationship.

Each record linked through pointers between the

member and the owner of record


NETWORK DATABASE CHARACTERISTICS

Divided into 3 parts :

RECORD

Records contain a group of related data.

TYPES OF RECORD

Coordinator records describe a group structure for storing

information records of the same type

DATA ITEM

Attribut or field . Consist of name and format.


NETWORK DATABASE DATA STRUCTURE

No_Pelajar Nama Alamat T_Lahir

PELAJAR

Data Item

Data Item Format No_Pelajar CHAR 8 Nama VARCHAR 25 Alamat VARCHAR 40 T_Lahir CHAR 8


NETWORK DATABASE DATA STRUCTURE

- Explanation of the relationship between the two types of records in

the ratio 1: M

- Each SET type has three elements :

* name (for SET type)

* the owner record types

* member records.

JABATAN

JAB_UTAMA set

PELAJAR

SET Type : JAB_UTAMA

Owner Record Type : JABATAN

Member Record Type : PELAJAR

Relationship Type : 1 : M


SET TYPE

- There are several types of instance set in the type set.

- Each instance record set built by one owner and several records from the type of

record.

ACCOUNTING

AIMAN

Member record of Department Accounting : Aiman, Muthu, Azlan

Member record of Department Marketing : Farhana, Firdauz, Arif

This figure shows two examples of instance and relationship 1: M between records STUDENT and

DEPARTMENT

MUTHU AZLAN

MARKETING

FARHANA FIRDAUS ARIF


INSTANCE TYPE

Conditions of member set

Divided into two conditions:

i. Insertion Option

ii. Retention Option


SET & INSTANCE TYPE

- Occurs when one member record is inserted into the DB.

- The records inserted with STORE command.

- There are two options for Insertion :

i. AUTOMATIC

new member record are automatically connected to

the instance set when the records are stored in the

database

ii. MANUAL

new member record can not be included in the

instance set until the CONNECT command executed

INSERTION OPTION


- Occurs when a record of the type of record exists of itself in DB .

or must always have a relationship with the owner of record, thus

becoming a member of the set of instance.

- There are three options set for Retention :

i. OPTIONAL

* A record of the members come up with their own without being a

member of any particular set of instance.

* It can be connected or disconnected with the instance set via the

CONNECT command or DISCONNECT.

RETENTION OPTION


ii. MANDATORY

* A member record can not exist on its own.

* It must always be a member of the set of instance for a specific

set of types

* the member record can be connected to another set of instance through

RECONNECT command.

iii. FIXED

* A member record can not exist on its own.

* It must always be a member of the set of instance for a specific set of types

but can not be connected to another set of instance.


RETENTION OPTION

- Members record in one instance can be sort according a few options.

- Options : SORT, SYSTEM DEFAULT, FIRST, LAST, NEXT and PRIOR.

i. SORT

Member record can be sort according to ascending or descending.

ii. SYSTEM DEFAULT

A new member record entered the database in any position according

to the system.

iii. FIRST

A new member record entered the database can be the first record in

the instance.

SORTING SET


iv. LAST

A new member record entered the database can be the last record in

the instance.

v. NEXT

* A new member record entered the database after the last record

used in the database.

* At least one record must exist in the instance set

vi. PRIOR

* A new member record entered the database can be before the last

record entered in the instance.

SORTING SET


DEFINITION

Although many different types of data-modeling tools

have been developed during the past decade, the

entity relationship (ER) model or ERM is a widely

accepted and adapted graphical tool for data modeling.

ER models are normally represented in any entity

relationship diagram (ERD), which uses graphic

representations to model the database components.

ENTITY RELATIONSHIP MODEL

ERD COMPONENTS


PAINTER paints PAINTING

1 M

entity box relationship

connectivity

EMPLOYEE learns SKILL

M N

EMPLOYEE manages STORE

1 1

ADVANTAGES vs DISADVANTAGES


ADVANTAGES

Visual representation

Effective communication tool

Integrated with the relational data model

DISADVANTAGES

Limited constraint representation

Limited relationship representation

No data manipulation language

DEFINITION

Object Oriented (OO) concepts have been used since the 1970s.

An object is an abstraction of a real world entity an object represents only ONE individual occurrence of an entity.

Attributes describe the properties of an object.

CUSTOMER name, address, ic no

Class a collection of similar objects with shared attributes and behaviour (methods)

Inheritance ability of an object within the class hierarchy to inherit the attributes and methods of the classes above it.

OBJECT ORIENTED MODEL

OBJECT ORIENTED COMPONENTS


INVOICE

CUSTOMER

LINE

INV_DATE

INV_NO

INV_SHIP_DATE

INV_TOTAL

1

M

object

attributes

relationship

ADVANTAGES vs DISADVANTAGES


ADVANTAGES

Adds semantic content

Database integrity

Visual presentation includes semantic content

DISADVANTAGES

Complex navigational data access

High system overhead slows transactions

semantic = meaning

DEFINITION

The semantic data model is a software

engineering model based on relationships

between stored symbols and the real world.

The data is organized in such a way that it can be

interpreted meaningfully without human

intervention. Semantic data has a history dating

back to the 1970's and is currently used in a wide

variety of data management systems and

applications.

HOW DOES IT WORKS?

Data is organized based on binary models of objects, usually in groups

of three parts: two objects and their relationship.

For example, if one wanted to represent a cup sitting on a table, the

data organization might look like this: CUP TABLE. The objects (cup and

table) are interpreted with regard to their relationship (sitting on). The

data is organized linearly, telling the software that since CUP comes first

in the line, it is the object that acts. In other words, the position of the

word tells the software that the cup is on the table and not that the

table is sitting on the cup.

Databases designed around this concept have greater applicability and

are more easily integrated into other databases.

DEFINITION

In conventional database systems, procedures, data structures and actual

content are usually separated. Thus, a conventional database

management systems (DBMS) provides users with a possibility to store,

modify or retrieve data that structured in accordance with a current

database schema.

DEFINITION In contrast, the functional data model provides an unified approach to

manipulation both data and procedures.

Main idea of the functional data model is a definition of all components

of an information system in the form of functions.

Thus, for example, the functional data model defines data objects,

attributes and relationships as so-called database functions.

Moreover, a Functional Data Manipulation Language is a number of data

manipulation functions which can be applied to database functions.

This model describes how data is

stored in the computer.

It provides information such as the

structure of the records, organize

records and access routes.

Database Schema

The description of a database. Includes description of the database structure

and the constraints that should hold on the database. The database schema

changes very infrequently.

Schema Diagram

A diagrammatic display of database schema. Schema is also called intension.

Database Instance

The actual data stored in a database at a particular moment in time. Also called

database state (or occurrence). The database state changes every time the

database is updated. State is also called extension.

Name ID_No Class Unit

STUDENT

CourseName CourseCode Kredit_Hr Department

COURSE

SubjectName SubjectCode Year Semester

SUBJECT

Lecturer

ID_No SubjectCode Grade

GRADE

Descriptive language allowing the

database manager or users out or

insert entities required for the

application and the relationship

between different entities

Language that provides a set of operations to

support basic data manipulation operations on the

database.

Operation data includes:

* New data entry

* Change the new data

* Access your data in the database

* delete data from the database

4GL means Fourth-Generation Language.

4GL is a non-procedural language, the user will define what is required

without having to know or define how it is generated.

4GL include:

* language like query language presentation and report.

* specific language as an electronic spreadsheet and

database languages .

* generation applications such as definition, entry,

updates and travel data from the database to build

applications.

* high-level language that is used to generate application code.

Application

program Queries

Database

schema

DML

preprocessor

Query

processor DDL compiler

Program

object code Database

manager

Dictionary

manager

Access

methods File manager

System

buffers Database and data

dictionary

Programmers Users DBA

DBMS

Data dictionary management

Data Storage management

Data transformation and presentation

Security Management

Multiuser Access Control

Backup and Recovery Management

Data integrity management

Database Access Languages and Application Programming

Interface

Database Communication Interfaces

Most DBMSs have database utilities that help the DBA in

managing the database system.

Common utilities have the following types of functions:

Loading

Backup

File Reorganization

Performance Monitoring

Loading:

A loading utility is used to load existing data files-such as

text files or sequential files-into the database.

Backup:

A backup utility creates a backup copy of the database,

usually by dumping the entire database onto tape. The backup copy

can be used to restore the database in case of catastrophic failure.

File reorganization:

This utility can be used to reorganize a database file into a different

file organization to improve performance.

Performance monitoring:

Such a utility monitors database usage and provides statistics

to the DBA. The DBA uses the statistics in making decisions such

as whether or not to reorganize files to improve performance.

Other utilities may be available for sorting files, handling data

compression, monitoring access by users, interfacing with the network,

and performing other functions.

Database Chapter 1

Documents

database system introduction

database system function

database structure

database environment

database administrators

logical database

vs database terminologies

managed database terminologies