Introduction to database systems Database size and complexity What is DBMS? Characteristics of Database approach Users of database Advantages of using database system Database systems evolution When not to use database systems

1. Fundamentals of Database systems
Ministry of Higher Education
Bamyan University
Computer Science Department
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Presented by : Mustafa Kamel Mohammadi
Email : bamian.cs@gmail.com
Databases and Database Users
Fundamentals of database system 6th edition

2. Agenda of course
 Database design and implementation
 Database systems introduction and concepts
 Database system architecture
 Relational Database design
 Relational algebra
 SQL
 ER modeling
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3. learning objective
 In this chapter you will learn
 Introduction to database systems
 Database size and complexity
 What is DBMS?
 Characteristics of Database approach
 Users of database
 Advantages of using database system
 Database systems evolution
 When not to use database systems
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4. Introduction
 Databases and database systems are an essential component of life in modern
society and used in different fields
 Schools
 Universities
 Online marketing
 Airline reservation
 Digital Libraries
 Markets
 Inventories
 Companies
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5. Introduction (cont..)
 ERP (Enterprise Resource Planning) systems
 HR (Human resource)
 Finance
 Costumer relationship
 Supply
 Hospitals
 Geographical org
 Weather predictions
 Communication
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6. Types of Database systems
 Traditional database
 information that is stored and accessed is either textual or numeric
 Multimedia databases
 store images, audio clips, and video streams digitally
 Geographic information systems
 can store and analyze maps, weather data, and satellite images
 Data warehouses and online analytical processing (OLAP) systems
 Extract and analyze useful business information from very large databases to support
decision making
 Real-time and active database technology
 used to control industrial and manufacturing processes
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7. Definition
 A Database is a collection of logically related data
 Data = facts that can be recorded and that have implicit meaning like names, telephone
numbers, and addresses of the people
Database properties
 Represents some aspect of the real world.
 Database is a mini world.
 Designed, built, and populated with data for a specific purpose.
 It has some group of users and applications that use database.
 Has degree of interaction through application
 User is actively interested in it’s content
 Has source from which data is derived
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9. Size and Complexity
 A Database can be of any size and complexity
 According to size
 As small to store few hundreds of records like a contact list
 As big like Google ….
 According to complexity
 Less complex like a simple insertion and retrieval system
 More complex like amazon, Facebook , financial systems
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10. DBMS (Database management system)
 A collection of programs that enables users to create and maintain a database.
 It Manages Database files the same as “Windows Explorer” manages files in
Drives.
 A General-purpose software system that facilitates the
 Defining
 Involves specifying the data types, structures, and constraints of the data
 Constructing
 the process of storing the data on some storage medium
 Manipulating
 Retrieving , updating, deleting records
 Sharing
 allows multiple users and programs to access the database simultaneously
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11. Cont.
 Other functions of DBMS
 Protection : protecting against hardware and software malfunction
 Security : protecting against unauthorized access
 Maintaining : allow the system to evolve as requirements change over time
 Application program accesses the database by sending queries or requests for
data to the DBMS
 Query typically causes some data to be retrieved
 Database and DBMS software together a Database System
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12. Characteristics of Database approach
1-Self-Describing Nature of a Database System
The database system contains not only the data itself but also a complete
definition
Definition is stored in the DBMS catalog
 Information such as the structure of each file, the type and storage format of each data item,
and various constraints on the data
The information stored in the catalog is called meta-data
In traditional file processing, data definition is typically part of the application
programs themselves
DBMS software refers to the catalog to determine the structure of the database
elements
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14. Cont.
2-Insulation between Programs and Data , and Data Abstraction
In file processing, changes to the structure of a file may require changing all
programs that access that file
In database approach changes in database may not require changes in application
level
We call this property program-data independence
In object oriented approach operations are also defined which causes program
operation independence
The characteristic that allows program-data independence and program-
operation independence is called Data abstraction
 hides storage and implementation details from most database users
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15. Cont.
3-Support of Multiple Views of the Data
A Database typically has many users, each of whom may require a different view
of the database
A view may be a subset of the database
It may contain virtual data that is derived but not explicitly stored.
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16. Cont.
4-Sharing of Data and Multiuser Transaction Processing
Sharing allow multiple users to access the database at the same time
 The DBMS must include concurrency control software
Transaction is an executing program or process that includes one or more
database accesses
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17. Actor of Database
 Small database
 one person typically defines, constructs, and manipulates the database, and there maybe no
sharing
 Large scale database
 many people are involved in the design, use, and maintenance of a large database with
hundreds of users with different responsibilities
 Actors on the scene
 people whose jobs involve the day-to-day use of a large database
 Workers behind the scene
 those who work to maintain the database system environment but who are not actively
interested in the database contents
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18. Actors on the Scene
 Database designer
 Communicate with all database users to understand their requirements
 Responsible for identifying the data to be stored in the database
 Choosing appropriate structures to represent and store this data
 Develop views of the database that meet the data and processing requirements
 Database administrator
 Manage primary and secondary resource ( Database and DBMS software)
 Authorizing access to the database
 Monitoring its use
 Acquiring software and hardware resources as needed
 Fix security gaps and poor system response time
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19. Cont.
End users:
Casual end users
 Occasionally access database but use a sophisticated database query language
 Middle or high-level managers
Naive end users
 Using standard types of queries and update called canned transactions
Sophisticated end users
 Are familiar with Database Queries or Database Languages
 Like engineers, scientists, business analysts.
 Standalone users
 Using ready-made program packages that provide easy-to-use menu-based or graphics-
based interfaces
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20. Cont.
System Analyst
 System analysts determine the requirements of end users
Application Programmers
 Application programmers implement these specifications as programs
 They test, debug, document, and maintain database transactions.
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21. Actors behind the Scene
DBMS designer and implementers
Design and implement the DBMS modules and interfaces
Tool developers
design and implement tools
 software packages that facilitate database modeling and design, performance monitoring ….
Operators and maintenance personnel
responsible for the actual running and maintenance of
 hardware
 software
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22. Advantages of using Database
1-Controlling Redundancy
In traditional file processing every user of the system has his/her own file
independently for recording data
 Some data might be recorded multiple times in different places.
Redundancy (storing the same data multiple times) leads to several problem
 Duplication of operation
 Storage space is wasted
 Inconsistency
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23. Cont.
2-Restricting Unauthorized Access
When multiple users share a large database, most users will not be authorized to
access all information in the database
 Retrieval
 Deletion
 Update
 DBMS should provide a security and authorization subsystem
 DBA create accounts and to specify account restrictions
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24. Cont.
3-Providing Persistent Storage for Program Objects
The main reasons for object-oriented database systems
Two types of object
 Transient objects
 Persistent objects
Object oriented DBMSs transform transient object to persistent
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25. Cont.
4-Providing Storage Structures and Search Techniques for Efficient Query
Processing
Database systems must provide capabilities for efficiently executing queries and
updates by
 Specialized data structures
 Search techniques to speed up disk search
5-Providing Backup and Recovery
Must provide facilities for recovering from hardware or software failures
Backup and recovery subsystem of the DBMS is responsible
 Recovery by transactions
 In case of failure in query processing
 Disk backup and recovery
 In case of disk failure
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26. Cont.
6-Representing Complex Relationships among Data
database may have too much entities that can have complex an numerous
relationship with each other
A DBMS must have the capability to
 Define relationship between entities
 Retrieve data according to specified relationship
7-Providing Multiple User Interfaces
DBMS should provide a variety of user interfaces for group of users
 Query languages interface
 Programming language interfaces for application programmers
 Forms
 menu-driven interfaces
known as graphical user interfaces (GUIs)
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27. Cont.
8-Enforcing Integrity Constraints by :
 Specifying a data type for each data item
 Key or uniqueness constraint
 Business rules
9-Permitting Inference and Actions Using Rules
Deductive database systems
 Capabilities for defining deduction rules for inferring new information from the stored
database facts
Active database systems
 Automatically initiate actions when certain events and conditions occur.
 Triggers and events
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28. Cont.
Additional implications for using database approach
Potential for Enforcing Standards
Reduced Application Development Time
Flexibility
Availability of Up-to-Date Information
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29. History and evolution of Database systems
Network and hierarchical systems
Relational Databases
Object-Oriented Applications and the Need for More Complex Databases
Interchanging Data on the Web for E-Commerce Using XML
Extending Database Capabilities for New Applications
 Scientific applications
 Storage and retrieval of images and videos
 Data mining applications and analyzing large amounts of data
 Spatial applications that store spatial locations of data … GIS,GPS
 Time series applications
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30. When Not to Use a DBMS
The overhead costs of using a DBMS are due to the following
High initial investment in hardware, software, and training
The generality that a DBMS provides for defining and processing data
Overhead for providing security, concurrency control, recovery
Use regular files under the following circumstances
Simple, well-defined database applications that are not expected to change at all
Embedded systems with limited storage capacity
No multiple-user access to data
Real-time requirements for some application programs that may not be met
because of DBMS overhead
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31. Exercise
• Discuss the main characteristics of the Database approach and how it differs from
traditional file systems.
• What are the responsibilities of the DBA and the database designers?
• Email: bamian.cs@gmail.com
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