database and management-chapter1 part 1
TRANSCRIPT
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Introduction
Today, more than at any previous time,
the success of an organization depends on its
ability to acquire accurate and timely data
about its operations, to manage this data
effectively, and to use it to analyze and guide
its activities.
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Definition of Terms:
Data
It is a stored representation of objects and events that have
meaning and importance in the usersenvironment.
referred to facts concerning objects and events that could be
recorded and stored on computer media. Structured: numbers, character, dates
Unstructured/Multimedia: images, sound, video segments,
documents, maps, emails
Information
It is a data that have been processed in such a way as to increase
the knowledge of the person who uses the data.
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Figure 1-1a Data in context
Context helps users understand data
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Graphical displays turn data into useful information
that managers can use for decision making and
interpretation
Figure 1-1b Summarized data
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Definition of Terms: (Contd)
Database
It is an organized collection of logically related data.
MetadataThese are data that describe the properties or characteristics of
end-user data and the context of that data.
It is also refer to Dataabout data.
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Descriptions of the properties or characteristics of the data,
including data types, field sizes, allowable values, and data
context
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Hierarchy of Data
Bit
It is the smallest unit of data (0 and 1).
Byte
It consist of 8 bits; collection of bits; it is a character.
Field It is a group of characters that form a word
Record
It is a collection of related field.
Files It is a collection of records.
Database
It is collection of interrelated files.
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File Processing Systems
A file processing system is the process of creating,
storing and accessing content of files.
It is also a collection offiles
and programs thataccess/modify these files. Typically, new files and
programs are added over time (by different
programmers) as new information needs to be stored
and new ways to access information are needed.
File
It is a collection of related records.
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Figure 1-2:Old file processing systems
at Pine Valley Furniture Company
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Disadvantages of File Processing
Program-Data Dependence All programs maintain metadata for each file they use
Duplication of Data
Different systems/programs have separate copies of the samedata
Limited Data Sharing No centralized control of data
Lengthy Development Times Programmers must design their own file formats
Excessive Program Maintenance 80% of information systems budget
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Figure 1-2:Old file processing systems
at Pine Valley Furniture Company
Data Dependency / Duplicate Data
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Problems with Data Dependency
Each application programmer must maintain his/her own
data
Each application program needs to include code for the
metadata of each file
Each application program must have its own processing
routines for reading, inserting, updating, and deleting
data
Lack of coordination and central control
Non-standard file formats
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Problems with Data Redundancy
Waste of space to have duplicate data
Causes more maintenance headaches
The biggest problem:
Data changes in one file could cause inconsistencies
Compromises in data integrity
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SOLUTION:
The DATABASE Approach
Central repository of shared data
Data is managed by a controlling agent
Stored in a standardized, convenient form
Requires a Database Management System
(DBMS)
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Database Management System
A Database Management Systems is a software systemthat is used to create, maintain, and provide controlledaccess to user databases.
It facilitates the processes of defining, constructing, and
manipulating
databases for various applications. Defining a database involves specifying the data types,
structures, and constraints for the data to be stored in thedatabase.
Constructing the database is the process of storing the data itselfon some storage medium that is controlled by the DBMS.
Manipulating a database includes such functions as querying thedatabase to retrieve specific data, updating the database toreflect changes in the miniworld, and generating reports from thedata.
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Order Filing
System
Invoicing
System
PayrollSystem
DBMSCentral database
Contains employee,
order, inventory,
pricing, and
customer data
Figure 1-3:DBMS approach
at Pine Valley Furniture Company
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Advantages of the Database
Approach
Program-Data Independence
The separation of data descriptions (metadata) from the
application programs that use the data.
Planned Data Redundancy
Improved Data Consistency Improved Data Sharing
It facilitate a User Viewwhere it is a logical description of
some portion of the database that is required by a user to
perform some task.
Increased Application Development Productivity
Enforcement of Standards
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Advantages of the Database
Approach (contd)
Improved Data Quality A constraint is a rule that cannot be violated by database users.
Improved Data Accessibility and Responsiveness
Reduced Program Maintenance
Improved Decision Support
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Costs and Risks of the Database
Approach
New, Specialized Personnel
Installation and Management Cost and Complexity
Conversion Costs
Need for Explicit Backup and Recovery Organizational Conflict
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Elements of the Database
Approach Data models
Graphical systems used to capture the nature and relationships
among data. (Entity, Attributes, Relationships)
Enterprise Data Modelhigh-level entities and relationships forthe organization
Project Data Modelmore detailed view, matching data structurein database or data warehouse.
Relational DatabasesA database that represents data as a collection of tables in which
all data relationships are represented by common values in
related tables.
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Elements of the Database
Approach Database Applications
Application programs used to perform database activities for
database users.
Activities: Createto add new data to the database.
Readto read current database data.
Updateto modify current database data.
Deleteto delete current data from the database.
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Figure 1-4:Components of the Database Environment
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Components of the
Database Environment Computer
Aided Software Engineering (CASE) Tools
Software tools that provide automated support for some portionof the systems development process.
Repository
A centralized knowledge base of all data definitions, datarelationships, screen and report formats, and other systemcomponents; centralized storehouse of metadata.
Database is an organized collection of logically related data, usually
designed to meet the information needs of multiple users in anorganization; storehouse of the data
Database Management System (DBMS) is a software system that is used to create, maintain, and provide
controlled access to user databases; software for managing the
database
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Components of the
Database Environment (contd) Application ProgramsComputer-based application programs are used to create and
maintain the database and provide information to users; softwareusing the data
User InterfaceText and graphical displays to users
Data/Database AdministratorsPersonnel responsible for maintaining the database
System DevelopersPersonnel responsible for designing databases and software
End UsersPeople who use the applications and databases
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The Range / Categories of
Database Applications
Personal Databases
It is designed to support one user. The purpose of these
databases is to provide the user with ability to manage (store,
update, delete, and retrieve) small amounts of data in an efficient
manner.
Two-Tier Client/Server Database
It is a relatively small team of people (typically fewer than 25
persons).
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Figure 1-5: Two-Tier Client/Server Database
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The Range / Categories of
Database Applications (contd)
Multitier Client/Server Databases
It is intended to support a department (such as marketing or
accounting) or a division (such as a line of business), which is
generally larger (typically between 25 and 100 persons).
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Figure 1-6: Multitier Client/Server Database
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The Range / Categories of
Database Applications (contd)
Enterprise Applications
Enterprise resource planning (ERP) systems
A business management system that integrates all functions
of the enterprise, such as manufacturing, sales, finance,
marketing, inventory, accounting, and human resources. ERPsystems are software applications that provide the data
necessary for the enterprise to examine and manage its
activities.
Data warehousing implementationsAn integrated decision support database whose content is
derived from the various operational databases.
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Figure 1-7: An enterprise data warehouse
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The Range / Categories of
Database Applications (contd)
Web-Enabled Database
Extranet communication
Business-to-Consumer (B2C)
Business-to-Business (B2B)
Intranet communication
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Table 1-8: Summary of Database Applications
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Evolution of Database Systems
Figure 1-9: Evolution of database technologies
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Evolution of Database Systems
(Contd)
Human beings began to store information very long ago.
Where programming became the foundation of creating
enterprise computer systems. The systems developed, needed
to store its data somewhere and the programmers designed
more or less proprietary and specialized solutions for thispurpose.
1960S
Two models:
Network Model, was designed by Charles Bachman at
General Electric called Integrated Data Store and standardized
by the Conference on Data Systems Languages (CODASYL) .
Hierarchical Model, Rockwell collaborates with IBM to create
the Information Management System (IMS).
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Evolution of Database Systems
(Contd) 1970s
Ted Codd at IBMs San Jose Lab proposed relational models.
Peter Chen defined the Entity-relationship(ER) model (1976)
1980s
Structured Query Language (SQL), became the standard querylanguage.
Object-oriented DBMS (OODBMS) develops. (1985)
1990s
Incorporation of object-orientation in relational DBMSs. (Object-
relational)
First Internet database applications (1995)
2000s
Database applications continue to grow, the three leading database
companies in the western world are Microsoft, IBM, and Oracle.
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Evolution of Database Systems
(Contd)
Figure 1-10: Pictorial representation of Database
Evolution over decades
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The END