This document provides an introduction to database systems. It defines key concepts like data, databases, database management systems (DBMS), and file systems. It describes the evolution from manual data handling to file-based systems to modern database approaches. The database approach provides benefits like reducing data redundancy, improving data sharing and security. Actors involved with databases like database administrators, designers, and end users are also outlined. Basic database terminology is defined, including entities, attributes, records, files and different database models.

1. Fundamentals of Database
system
Chapter one:
Introduction to
database system
Prepared by:
Misganaw Abeje
University of Gondar
College Of Informatics
Department of computer science
Misganaw.Abeje13@gmail.com

2. Outline
 What is data
 What is database and DBMS
 Characteristics of database
 Data base system and file system
 Advantages of DB approach and its characteristics
 Actors on Scene
 Database Terminology
BY: MA

3. Data
 Data are the raw (unorganized) facts about things like
people, places, events or concept that have inherent
meaning, which is useless By themselves ).
 The decision maker really needs is information,
 Databases and database technology are having a
major impact on the growing use of computers.
 Databases play a critical role in almost all areas where
computers are used, including business, engineering,
medicine, law, education, and library
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4. What is database?
 database is a collection of related data. E.g. Address book
.An address book mainly contains the name, telephone number
and address.
 A database is a well organized, logically related and shared
collection of data that is designed to meet the information
needs of various users in an organization.
 The database is an integrated collection of facts about an
organization.
– Organization can be a University, Insurance companies, Banks,
Airlines, Governmental and Non-governmental Organizations etc.
 The database is used as a central data source for other
applications
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5. Implicit properties of database:
 A database represents some aspect of the real
world
 Database is a logically coherent collection of
data with some inherent meaning
 A database is designed, built, and populated
with data for a specific purpose.
 In other words, the interaction with events in the
real world.
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6. What is database management system (DBMS)
 It is a collection of programs that enables users to create
and maintain a database.
 The DBMS is hence a general-purpose software system
that facilitates the processes:
– Defining a database: involves specifying the data types,
structures, and constraints for the data to be stored in the
database.
– Constructing the database: is the process of storing the data
itself on some storage medium that is controlled by the DBMS.
– Manipulating a database includes such functions as querying the
database to retrieve specific data, updating the database to reflect
the mini-world, and generating reports from the data.
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7. Data base system and file system
 Data management passes through the different levels of
development.
 These levels could best be described by categorizing
the levels into three levels of development. Even though
there is an advantage and a problem overcome at each
new level.
 The major three levels are;
1. Manual Approach
2. Traditional File Based Approach
3. Database Approach
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8. Manual File Handling Systems
 In this approach, data storage and retrieval follows the
primitive and traditional way of information handling where
cards and paper are used for the purpose performed using
human labor.
 Each of the files containing various kinds of information is
labeled and stored in one or more cabinets.
 The cabinets could be kept in safe places for security
purpose based on the sensitivity of the information contained
in it.
 Insertion and retrieval is done by searching first for the right
cabinet then for the right file then the information.
 Some Examples Personal Calendar, personal profile
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9. Limitations of the Manual approach
– Prone to error
– Difficult to update, retrieve, integrate
– You have the data but it is difficult to compile the
information
– Limited to small size information
– Cross referencing is difficult
 An alternative approach of data handling is a
computerized way of dealing with the information.
 Two computerized approaches evolved:
– – File based approach → decentralized
– – Database approach→ centralized
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10. File-Based Approach
 File based systems were an early attempt to
computerize the manual filing system by use of
computer system.
 This approach is the decentralized computerized data
handling method.
 A collection of application programs perform services
for the end-users. In such systems, every application
program that provides service to end users define
and manage its own data
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11.  Such systems have number of programs for each of
the different applications in the organization.
 Since every application defines and manages its
own data, the system is subjected to serious data
duplication.
 File, in traditional file based approach, is a collection
of records which contains logically related data.
 This approach is to develop a number of programs
for each different application
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12. Limitations of the Traditional File
Based approach
 Data Redundancy (Duplication of data)
– Same data is held by different programs and Wasted space
 Separation or Isolation of Data: Available information
in one application may not be known.
 Limited data sharing
 Lengthy development and maintenance time
 Data dependency on the application
– Each application program must have its own processing
routines
 Incompatible file formats (Lack of Data Sharing and
Availability)
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13. Cont…
 Data Inconsistency and confusion
 Poor Security and administration
 The limitations for the traditional file based data
handling approach arise from two basic reasons.
1. Definition of the data is embedded in the application program
which makes it difficult to modify the database definition
easily.
2. No control over the access and manipulation of the data
beyond that imposed by the application programs. The most
significant problem experienced by the traditional file based
approach of data handling is the “update anomalies”
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14. Cont…
We have three types of update anomalies;
1. Modification Anomalies: a problem experienced when one or
more data value is modified on one application program but not
on others containing the same data set.
2. Deletion Anomalies: a problem encountered where one
record set is deleted from one application but remain
untouched in other application programs.
3. Insertion Anomalies: a problem experienced whenever there
is new data item to be recorded, and the recording is not made
in all the applications. And when same data item is inserted at
different applications, there could be errors in encoding which
makes the new data item to be considered as a totally different
object.
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15. Database Approach
 To become more effective, database approach is required.
 A Database Approach is shared collection of logically
related data, designed to meet the information needs of an
organization. (Centralized System).
– Shared collection – can be used simultaneously by
many departments and users.
– Logically related - comprises the important objects and
the relationships between these objects.
– Description of the data – the system catalog (data
dictionary or meta-data) provides description of data to
enable data independence (program–data independence).
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16. Cont..
 Database is a collection of logically related data where these
logically related data comprises entities, attributes,
relationships, and business rules of an organization's info.
 Database is just a computerized record keeping system
 In addition to containing data required by an organization,
database also contains a description of the data which called
as “Metadata” or “Data Dictionary” or “Data about Data”. Since
it is called a self descriptive collection on integrated records.
 The purpose of a database is to store information and to allow
users to retrieve and update that information on demand.
 Database is designed once and used simultaneously by many
users.
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17. Characteristics of database approach
 A number of characteristics distinguish the
database approach from the traditional
approach of programming with files.
 Self-Describing Nature of a Database System
 Insulation between Programs and Data, and Data
Abstraction
 Support of Multiple Views of the Data
 Sharing of Data and Multiuser Transaction Processing
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18. Advantages of Using the DBMS Approach
 Controlling Redundancy
 Restricting Unauthorized Access
 Providing Backup and Recovery
 Data Abstraction
 Data Independence
 Support Multiple view for different Users
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19. Actors on the Scene
 Database Administrators:
– The DBA is responsible for authorizing access to the
database, for coordinating and monitoring its use,
and for acquiring software and hardware resources
as needed.
– The DBA is accountable for problems such as
breach of security or poor system response time.
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20.  Database Designers:
– Database designers are responsible for identifying the
data to be stored in the database and for choosing
appropriate structures to represent and store this data.
– These tasks are mostly undertaken before the
database is actually implemented and populated with
data.
– It is the responsibility of database designers to
communicate with all prospective database users, in
order to understand their requirements.
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21.  End Users:
– End users are the people whose jobs require access
to the database for querying, updating, and
generating reports.
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22.  System Analysts and Application Programmers
(Software Engineers)
– determine the requirements of end users, especially
naive and parametric end users, and develop
specifications for canned transactions that meet these
requirements.
– Application programmers implement these specifications
as programs; then they test, debug, document, and
maintain these canned transactions.
– Such analysts and programmers (nowadays called
software engineers) .
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23. Basic Database Terminologies
 Enterprise
– an organization : A library, a bank, a university, etc.
 Entity
– Person, place, thing, or event (property of an entity)
– An "object" in the real world that we are interested in:
– The object student is an entity
 Attribute (Field)
– A character or group of characters (alphabetic or numeric),
that has a specific meaning. Eg. Name, age, telephone,
grade, sex, etc.
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24.  Record
– A logically connected set of one or more Attributes
that describe a person, place or thing. (Logically
related data)
 File
– A collection of related records. For example, a file
might contain data about customers; or students of a
certain department in a university.
 Database
– Collection of Files
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25. Different database models
 Hierarchical data model
– Organize data in a tree structure
– There is a hierarchy of parent and child
– Data modeling to be one-to-many
 Network data model
– The same as hierarchical, but network model
permits the modeling of many-to-many
relationship
– A child can have more than one parent
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26.  Relational data model
– Stores data in the form of tables
– A table is a collection of records
– Each table corresponds to an entity
– Allows the definition of data and integrity constraints
 Object-oriented data model
– Faster than relational database model
– Applications require less code
– Add database functionality to object programming
language
BY: MA

27.  Thank you?
BY: MA