INTRODUCTION TO INFORMATION
SYSTEMS
LECTURE 8: DATABASE FEATURES,
FUNCTIONS AND ARCHITECTURES
PART (1)
‫ غدير عاشور‬/‫أ‬
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Learning Objectives
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1.
2.
3.
Explain the business value of implementing data
resource management processes and technologies
in an organization.
Outline the advantages of a database
management approach to managing the data
resources of a business, compared to a file
processing approach.
Explain how database management software
helps business professionals and supports the
operations and management of a business.
Learning Objectives
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Provide examples to illustrate each of the
following concepts:
4.
a.
b.
c.
d.
e.
Major types of databases
Data warehouses and data mining
Logical data elements
Fundamental database structures
Database development
Database Management
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


Data resource must be organised and structured in
logical way to be accessed easily, processed
efficiently, retrieved quickly and managed
effectively.
There are different data structures and access
methods that are ranged from simple to complex
that have been devised to organise and access
data.
Database developers need to understand how data
are structured, stored and accessed.
Examples of logical data elements
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figure 8-1
Fundamental Data Concepts
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
Character: it is the most basic data element that can
be observed and manipulated and consist of:
Single alphabetic
 Numeric
 Other symbol


Field or data item: it is the next higher level of data
that:
Consists of grouping of related characters
 Represents an attribute (a characteristic or quality) of some
entity (object, person, place or event)
 Example: first name, last name, salary … etc

Fundamental Data Concepts
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
Record: collection of all the fields used to describe
the attributes of an entity
 Example:
 payroll
record consists of fields such as person’s name, social
security number (SSN) and rate of pay
 Normally,
the first field in a record is the unique
identifier for the record
 The
unique identifier is called primary key (PK)
 The value of primary key is constrained so that no two of its
values are equal.
 The columns of a unique key cannot contain NULL values.
Fundamental Data Concepts
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Primary keys may consist of a single attribute or multiple
attributes in combination.
 Example: student ID can be used as PK. As long as there is no one
share the same student ID number, we can always identify the
record of that student
 If no specific data can be found to serve as PK, the data base
designer can simply assign a record a unique sequential number
so that no two records will ever have the same PK


foreign key is a referential constraint between two tables
The foreign key identifies a column or a set of columns in one
(referencing) table that refers to a set of columns in another
(referenced) table
 The columns in the referencing table must be the primary key in
the referenced table

Fundamental Data Concepts
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
File or table: a group of related records
It has the form of rows and columns with no relationships or
links between records and fields
 Example: employee table would contains record of
employee of a firm


Database: an integrated collection of logically related
data elements
Databases contain data elements describing entities and
relationships among entities
 Most websites (such as Facebook, YouTube ... etc) are stored
as a fields, records, files or objects in large database

Electric Utility Database
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figure 8-2
Source: Adapted from Michael V. Mannino, Database Application Development and Design
(Burr Ridge, IL: McGraw-Hill/Irwin, 2001), p. 6.
Database Structures
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

Database management systems (DBMS) packages
are designed to use a specific data structure to
provide end user with quick and easy access to
information stored in database
There are five fundamental data structures:
 Hierarchical
 Network
 Relational
 Object-oriented
 Multidimensional
Hierarchical Structure
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

Early DBMS structure
Records arranged in tree-like structure
 All
records are dependant and arranged in multilevel
structures, consisting of one root and any number of
subordinate levels
 Root is the highest level of the hierarchy

Relationships are one-to-many because:
 Each
data element are related to only one element
above it
Hierarchical Structure
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figure 8-3:
Network Structure
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




Can represent more complex relationships
Used in some mainframe DBMS packages
Many-to-many relationships
Data element can be accessed by following one of
several paths
Example:
 Departmental
records can be related to more than one
employee record, and employee records can be
related to more than one project record (see figure 8-4)

Usually not found in the modern organisation
Network Structure
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figure 8-4:
Relational Structure
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




Most widely used structure for most modern database
in organisations
Data elements are viewed as being stored in twodimensional tables
Each row represents a single record in the file
Each column represents a single field in the file
Can relate data in one file with data in another file if
both files share a common data element

Example:

In figure 8-5, a manager might want to display an employee and
salary from the employee table, as well as the name of the
employee’s department from the department table, by using their
common department number field (Deptno) to join the two table
Relational Structure
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figure 8-5
Relational Operations
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There are three basic operations that can performed
on relational databases to create a useful set of
data:
 Select
 Create
a subset of records that meet a stated criterion
 Example: select employees who make more than
$30,000

Join
 Combine
two or more tables temporarily so user can
see relevant data in a form that looks like one big
table without having to go to each table separately
Relational Operations
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
Project
 Create
a subset of columns in a table that have been
created by the select and join operations
 By using this operation the user can view only the
columns that have the data necessary to answer a
particular question
Multidimensional Structure
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


Variation of relational model
Uses multidimensional structures to organize data
Data elements are viewed as being in cubes
 Each
side of the cube is considered as a dimension of
the data

Popular for analytical databases that support
Online Analytical Processing (OLAP)
Multidimensional Model
figure 8-6
Object-oriented Structure
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

Object oriented model is considered one of the key
technologies of a new generation of multimedia
web-based applications
Object consists of
 Data
values describing the attributes of an entity
 Operations that can be performed on the data

Encapsulation:
 Combine
data and operations (methods)
 Allows the object oriented to handle complex types of
data (pictures, graphics, voices and text)
Object-Oriented Structure
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
Inheritance:
 Supported
by object-oriented model
 New objects can be created by replicating some or all
of the characteristics of parent objects
 Example: in figure 8-7 the checking and saving account
objects can inherit both the common attributes and
operations of the parent bank account object
Object-oriented Structure
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figure 8-7
Source: Adapted from Ivar Jacobsen, Maria Ericsson, and Ageneta Jacobsen, The Object Advantage: Business Process
Reengineering with Object Technology (New York: ACM Press, 1995), p. 65.
Copyright @ 1995, Association for Computing Machinery. By permission.
Object-oriented Structure
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
Used in Object-oriented database management
systems (OODBMS)
 Example:
multimedia web-based applications for the
internet allow designers t develop product designs,
store them as objects in object-oriented database and
modify them to create new product designs

Supports complex data types that can work with
OODBMS
 Examples,
graphic images, video clips, web pages
Evaluation of Database Structures
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
Hierarchical data structure




Worked for structured routine transaction processing of many
business operations in the early years
Data can be represented by groups of records in a hierarchical
relationship
Can’t handle many-to-many relationships
Network data structure

More flexible than hierarchical



Can handle many-to-many relationships
Become popular for more types of business operations
Like the hierarchical structure, it is unable to handle ad hoc
requests because its relationships must be specified in advance
Evaluation of Database Structures
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
Relational data structure
 Enable
an end user to receive information easily in
response to ad hoc requests because not all of the
relationships among the data elements in organised
database need to be specified when the database is
created.
 Easier for programmers to work with
 Limitation of relational model:
 Not
as efficient or quick as hierarchical or network because
it cannot process large amounts of business transactions
 Cannot process complex high-volume applications as the
object-oriented model
Database Development
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

Database management packages allow end users to
develop the database
Database Administrator (DBA)


Is a person responsible for the design, implementation,
maintenance and repair of an organization's database
Database developers use Data Definition Language
(DDL) like oracle to:
Develop and specify the data contents, relationships and
structure
 Modify these specifications when necessary


These specification could be stored in data dictionary
Database Development
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
Data dictionary
 It
is database catalog containing metadata
 Metadata – data about data
 Example:
it contains the names and descriptions of all types
of data records
 Managed
by database management software
 Maintained by DBA
Database Development
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figure 8-8
Data Planning Process
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
Enterprise Model

Defines basic business process of the enterprise



Such as purchasing/receiving process
Defined by DBAs and designers with end users
Data Modeling

Defines relationships between data elements
Involves modelling the relationships among the entities involved in
the business process by using Entity Relationship Diagram (ERD)
 Entity Relationship Diagram (ERD): are simply graphical models of
the various files (tables) and their relationships contained within
the database
 See figure 8-9

Entity Relationship Diagram
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figure 8-9
Database Design Process
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
Logical design
 Two
frameworks
 Schema
– overall logical view of relationships
 Subschema – logical view for specific end users
 These
frameworks determine the physical design
 Data models for DBMS

Physical design
 Represents
logical views of data and relationships of
the database
 Describes
how data are stored and accessed on the storage
devices of computer system
Logical and Physical Database Views
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figure 8-10
Any Questions
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
For more information
 Refer

to chapter 5 - section 1
Next week preparation:
 Chapter
5 - section 2