2. After the completion of the unit,
students will be able to:
1. Concisely define the basic concept in
database system;
2. Name several limitations of conventional
file-based system;
3. Explain the advantages of database
approach; and
4. Identify the roles in Databases
Environment.
3. INTRODUCTION
Data
• raw material & unorganized facts that need to be processed
• known facts that can be recorded and that have implicit
meaning
• Stored representations of objects and events that have meaning
and importance in the user’s environment.
• Information in raw or unorganized form (such as alphabets,
numbers, or symbols) that refer to, or represent, conditions,
ideas, or objects. Data is limitless and present everywhere in
the universe.
4. Most data is being converted into a digital format
5. Categories of Data
Structured Data - organized in rows and columns in a rigidly
defined format so that applications can retrieve and process it
efficiently. Structured data is typically stored using a database
management system (DBMS).
- Ex. (Databases, Spread Sheets, etc.)
Unstructured Data - is unstructured if its elements cannot be
stored in rows and columns, which makes it difficult to query and
retrieve by applications.
- Ex. (Forms, Images, Audio, Movies, etc.)
7. Information
• Data that has been processed and arrange or organized in a
meaningful form is know as information.
• Data that have been processed for a purpose
• Data that have been interpreted and understood by the recipient
8. DATA VS INFORMATION
Data and Information are interrelated. Data usually refers to
raw data, or unprocessed data. It is the basic form of data;
data hasn’t been analyzed or processed in any manner.
Once the data is analyzed, it is considered as information.
9. Metadata
• is structured information that describes, explains, locates, or
otherwise makes it easier to retrieve, use, or manage an
information resource.
• Often called data about data or information about information.
• Data that describe the properties or characteristics of end-user
data, and the context of that data.
- Ex. Data Names, Definitions, Length (or size)
10.
11. Management
According to Theo Heimann, management has three different
meanings,
• Management as a Noun: refers to a Group of Managers.
• Management as a Process: refers to the Functions of
Management i.e. Planning, Organizing, Directing, Controlling,
etc.
• Management as a Discipline: refers to the Subject of
Management.
12. Management
• An individual or a group of individuals that accept
responsibilities to run an organization. They Plan, Organize,
Direct and Control all the essential activities of the
organization. Management does not do the work themselves.
They motivate others to do the work and co-ordinate (i.e. bring
together) all the work for achieving the objectives of the
organization.
• Management brings together all Six Ms i.e. Men and Women,
Money, Machines, Materials, Methods and Markets. They use
these resources for achieving the objectives of the organization
such as maximum sales and profits, business expansion, etc.
13. What is Information Management?
• Application of Management techniques to collect information,
communicate it within and outside the organization, and
process it to enable managers to make quicker and better
decisions.
• According to Wikipedia, Information Management (IM) is the
collection and management of information from one or more
sources and the distribution of that information to one or more
audiences.
14. What is Information Management?
• Information Management is a cycle of processes that support
the organization's learning activities: identifying information
needs, acquiring information, organizing and storing
information, developing information products and services,
distributing information, and using information (Choo, 1995).
• It is the management of organizational processes and systems
that acquire, create, organize, distribute, and use information.
15. What is Information Management?
According to a process view of information management, IM is a
continuous cycle of six closely related activities:
1. identification of information needs;
2. acquisition and creation of information;
3. analysis and interpretation of information;
4. organization and storage of information;
5. information access and dissemination;
6. information use
16. Why is Information Management Important?
Managing information is important to an organization because it
allows for increased knowledge, decreased inefficiency, and
better creation and implementation of action plans to address
areas of opportunity. Without successful management of
information, it is almost guaranteed that an organization will fail.
Reasons are described in three categories;
1. Managing your information saves you money
2. Managing your information makes you money
3. Managing your information keeps you out of trouble
18. Database Management System
Database - is an organized collection of logically related data.
Databases and database technology have a major impact on the
growing use of computers. It is fair to say that databases plays a
critical role in almost all areas where computers are used
including business, electronic commerce, engineering, medicine,
law, education, and library science.
19. Database Management System
Database - is an organized collection of logically related data.
Databases and database technology have a major impact on the
growing use of computers. It is fair to say that databases plays a
critical role in almost all areas where computers are used
including business, electronic commerce, engineering, medicine,
law, education, and library science.
20. What is DBMS?
• DBMS stands for Database Management System. It is a
collection of programs that enables users to create and
maintain a database. DBMS is a set of computer programs that
controls the creation, maintenance, and the use of a database.
• DBMS is a set of software programs that controls the
organization, storage, management, and retrieval of data in a
database. It is a special data processing system, or part of a
data processing system, which aids in the storage,
manipulation, reporting, management, and control of data.
21. What is DBMS?
DBMS is a general-purpose software system that facilitates the
processes of defining, constructing, manipulating, and sharing
databases.
• Defining a database involves specifying the data types,
structures, and constraints of the data to be stored in the
database.
• Constructing the database is the process of storing the data
on some storage medium that is controlled by the DBMS.
• Manipulating a database includes functions such as querying
the database to retrieve specific data.
• Sharing a database allows multiple users and programs to
access the data simultaneously.
22. Efficient data management requires the use of a computer
database, which is managed by a Database Management
System (DBMS)
23. Traditional File-Based Systems
File-Based Systems (FBS) is a collection of application programs
that perform tasks where each program defines and manages its
own data.
Limitations of File-Based Systems (FBS)
Isolation of Data
• Each software and each application manage its own data. The
users of one application might not know about the data
managed in other systems.
25. Redundancy
• Often the same data is managed more than once in different
applications. This needs more storage space and generates
higher costs for data capture and update. Occasionally, it is
difficult to find and correct inconsistent data.
27. Incompatible File Formats
• Since each application has its own file formats its hard or
impossible to exchange files between different applications.
• Limited Data Sharing – No centralized control of data
• Excessive Program Maintenance – 80% of information systems
budget
29. Database Approach
• Central repository of shared data
• Data is managed by a controlling agent
• Stored in a standardized, convenient form
30. Elements of the Database Approach
Data Model – Graphical system used to capture the nature and
relationships among data.
Enterprise data model – a graphical model that shows the high-level
entities for
the organization and the relationships among those entities.
Project Data Model – more detailed view, matching data structure in
database or data warehouse
Entity – a person, place, object, event, or concept in the user environment
about which the organization wishes to maintain data.
Relationship – between entities; usually one-to-many (1:M) or many-to-
many (M:M)
Relational Database – A database that represents data as a collection of
tables in which all data relationships are represented by common values in
related tables.
31. Advantages/Characteristics of Database Approach
Concurrent Use
• A database system allows several users to access the database
concurrently. Answering 12 different questions from different
users with the same (base) data is a central aspect of an
information system.
• An example for concurrent use is the travel database of a large
travel agency. The employees of different branches can access
the database concurrently and book journeys for their clients.
Each travel agent sees on his interface if there are still seats
available for a specific journey or if it is already fully booked.
32. Advantages/Characteristics of Database Approach
Structured and Described Data
• A fundamental feature of the database approach is that the
database system does not only contain the data but also the
complete definition and description of these data. These
descriptions are basically detailing about the extent, the
structure, the type and the format of all data and, additionally,
the relationship between the data. This kind of stored data is
called metadata ("data about data"). Data is called structured if
it can be subdivided systematically and linked.
33. Following is a simple example how data can be described in a
database.
34. Advantages/Characteristics of Database Approach
Separation of Data and Applications
• As described in the feature structured data, the structure of a
database is described through metadata which is also stored in
the database.
• A software application does not need any knowledge about the
physical data storage like encoding, format, storage place, etc.
It only communicates with the management system of a
database (DBMS) via a standardized interface with the help of a
standardized language like SQL. The access to the data and
the metadata is entirely done by the DBMS.
35.
36. Advantages/Characteristics of Database Approach
Data Integrity
• Data integrity is a by word for the quality and the reliability of the
data of a database system. In a broader sense data integrity
includes also the protection of the database from unauthorized
access (confidentiality) and unauthorized changes.
• A DBMS should support the task to bring only correct and
consistent data into the database. Additionally, correct
transactions ensure that the consistency is maintained during
the operation of the system.
37. An example for inconsistency would be if contradictory
statements were saved in the same database.
38. Advantages/Characteristics of Database Approach
Transaction
• A transaction is a bundle of actions which are done within a
database to bring it from one consistent state to a new consistent
state. In between the data are inevitable inconsistencies. Doing only
a part of the actions would lead to an inconsistent database state.
• One example of a transaction is the transfer of an amount of money
from one bank account to another. The debit of the money from one
account and the credit of it to another account makes together a
consistent transaction. This transaction is also atomic. The debit or
credit alone would lead to an inconsistent state. After finishing the
transaction (debit and credit) the changes to both accounts become
persistent and the one who gave the money has now less money on
his account while the receiver has now a higher balance.
39.
40. Advantages/Characteristics of Database Approach
Data Persistence
• Data persistence means that in a DBMS all data is maintained if
it is not deleted explicitly. The life span of data needs to be
determined directly or indirectly by the user and must not be
dependent on system features. Additionally, data once stored in
a database must not be lost.
• Changes of a database which are done by a transaction are
persistent. When a transaction is finished even a system crash
cannot put the data in danger.
41. Advantages/Characteristics of Database Approach
Data Views
• Typically, a database has several users and each of them,
depending on access rights and desire, needs an individual
view of the data (content and form). Such a data view can
consist of a subset of the stored data or from the stored data
derived data (not explicitly stored).
43. Example Applications
1. Management of Bank Accounts
The management of bank accounts are a demanding task which
has used database systems as aid for some time. Today, it is
unthinkable to operate in the very complex world of finances
without the help of database systems.
44. The most important characteristics of such database systems:
• Transaction. The successful and correct course of transactions
is very important when managing bank accounts. It cannot be
true that a credit is made to the wrong account or that a debit is
made more than once.
• Data Integrity is very important. It needs to be clearly defined
what the requirements and rules of consistency are and how
these can be followed.
• Data Persistence. For an owner of a bank account, it is
reassuring to know that the persistence of the data is
guaranteed. Data are not deleted arbitrarily or are lost
mysteriously.
45. Example Applications
2. Library Catalogue
The library catalogue NEBIS (Lierz et al. 2004) is the catalogue
of a network of libraries and information desks in Switzerland.
With the help of NEBIS it is possible to search for specific books
or publications in libraries all over Switzerland.
46. The most important characteristics of such database systems:
• Structured and Described Data It is more than helpful to have a
clearly defined structure when recording and updating several
thousands of books, magazines and publications. Additionally, the
description of the data allows to search selectively for specific
objects. Further, a clear structure is also free of redundancy. This
saves work as already a very small redundancy would lead to a
multiple of work.
• Data Views Depending on how detailed and specialized a search
should be done, a user needs more or less information from the
database. Thus, for a coarse search title and author might already
be sufficient. However, when looking for a specific edition of a book,
some more information is needed. With this in view the user can
choose between different data views. Additionally, there are views for
the manager of the catalogue which are not accessible by the public
user
47. Disadvantages of a DBMS
• Danger of an Overkill: For small and simple applications for single users
a database system is often not advisable.
• Complexity: A database system creates additional complexity and
requirements. The supply and operation of a database management
system with several users and databases is quite costly and demanding.
• Qualified Personnel: The professional operation of a database system
requires appropriately trained staff. Without a qualified database
administrator nothing will work for long.
• Costs: Through the use of a database system new costs are generated for
the system itself but also for additional hardware and the more complex
handling of the system.
• Lower Efficiency: A database system is a multi-use software which is
often less efficient than specialized software which is produced and
optimized exactly for one problem.
48. Roles in the Database Environment
1. The DA and DBA
• Data Administrator (DA) is responsible for the management of
the data resource, including database planning; development
and maintenance of standards, policies and procedures; and
conceptual/logical database design.
• Database Administrator (DBA) is responsible for the physical
realization of the database, including physical database design
and implementation, security, and integrity control, maintenance
of the operational system and ensuring satisfactory
performance of the applications for users.
49. Roles in the Database Environment
2. The Database Designers
• Logical Database Designer is concerned with identifying the data
(that is, the entities and attributes), the relationships between the
data, and the constraints on the data that is to be stored in the
database. The logical DB designer must have a thorough and
complete understanding on the organization’s data and any
constraints in this data (sometimes called business rules).
• Physical Database Designer decides how the logical database
design is to be physically realized. This involves mapping the logical
DB design into set of table and integrity constraints. Selecting
specific storage structures and access methods for the data to
achieved good performance and designing security features.
50. Roles in the Database Environment
3. The Application Developers
• Once the database has been implemented, the application programs
that provide the required functionality for the end-users must be
implemented. This is the responsibility of the application developers.
4. The End-Users
• The end-users are the “clients” of the database, which has been
designed and implemented and is being maintained to serve their
information needs. End-users can be classified according the way
they use the system.
• Naïve Users are typically unaware of the DBMS. They access the
DB through application programs that attempt to make the
operations as simple as possible.18 Sophisticated Users are familiar
with the structure of the DB and the facilities offered by the DBMS.
