lecture dbm1
TRANSCRIPT
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Learning Objectives
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Organisations need to process and organize largeamounts of data. Examples: Marketing manager: access customer data, their web habits and past
purchases
HR manager: Analyze the impact of raises, employee insurance benefitsand retirement contributions on long term costs to a company.
1. Illustrate the importance of managing data and the difficultiesinvolved.
2. Explain the business value of implementing data managementprocesses and technologies in an organization.
3. Outline the advantages of a database management approach tomanaging the data resources of a business, compared to a fileprocessing approach.
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Learning Objectives
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4. Explain how database management software helps
business professionals and supports the operations and
management of a business.
5. Provide examples to illustrate each of the followingconcepts:
Major types of databases.
Data warehouses and data mining.
Logical data elements.
Fundamental database structures.
Database development.
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Why Study Data Management?
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Todays business enterprises cannot survive or succeed without
qualitydata about their internal operations and external
environment.
The goal of data management is to provide the infrastructure
and tools to transform raw data into usable corporate
information of the highest quality.
Managers face constraintsto make intelligent business
decisions.
Data errors and inconsistencies lead to mistakes and lost opportunities,
such as failed deliveries, invoicing blunders, and problems synchronizing
data from multiple locations.
Data analysis errors as a result of inaccurate formulas or untested
models.
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Data Management
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It is a structured approach that applies information
systems technologies for capturing, storing,
processing, integrating, distributing, securing and
archiving data throughout theirlife cycle.
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Data Management: Challenges
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It is difficult to manage, search, and retrieve data located
throughout the enterprise? Reasons:
The volume of data
increases exponentially with time..
External data are constantly increasing in volume.
Data are scattered throughout organizations and are collected and created by
many individuals using different methods and devices.
Data are frequently stored in multiple servers and locations and also in different
computing systems, databases, formats, and human and computer languages.
Data security, quality, and integrity are critical
Legal requirements relating to data differ among countries, and they change
frequently.
Data throughout an organization may be redundant and out-of-date, creating
a huge maintenance problem for data managers.
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Organising Data
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It is essential to organize and maintain data in a
proper way to provide users with accurate, timely
and relevant information.
To understand the problem,
lets first study how systems arrange data in computer
files and traditional methods of file management.
Then, how the problems of traditional file management
are resolved by DBMS software.
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The Hierarchy of Data
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Bit (a binary digit):represents a circuit that is either on
or off
Byte:typically made up of eight bits
Character:a byte represents a character; the basic
building block of information
Can be an uppercase letter, lowercase letter, numeric digit,
or special symbol
Field:typically a name, number, or combination of
characters that describes an aspect of a business object
or activity
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The Hierarchy of Data (continued)
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Record:collection of related data fields
File:collection of related records
Database:collection of integrated and related files
Hierarchy of data
Bits, characters, fields, records, files, and databases
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The Hierarchy of Data (continued)
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The Hierarchy of Data (continued)
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Database
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Database:A database is a collection of information
organized in such a way that a computer program
can easily record and retrieve it.
Databases are organized into files, records, and fields.
Two basic types:
Centralized
Distributed Replicated
Partitioned
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DBMS
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Database management system (DBMS):group of
programs to manage database
Manipulates database
Provides an interface between database and the user
of the database and other application programs
Database administrator (DBA): skilled IS
professional who directs all activities related to anorganizations database
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Data Entities, Attributes, and Keys
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Entity: generalized class of people, places, or
things (objects) for which data is collected, stored,
and maintained Attribute:characteristic of an entity
Data item: specific value of an attribute
Key: field or set of fields in a record that is used to
identify the record
Primary key:field or set of fields that uniquely
identifies the record
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Data Entities, Attributes, and Keys
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Keys and Attributes
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Logical Data Elements
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Traditional File Processing
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Definition:
Data are organized, stored, and processed in independent files ofdata records
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Problems of File Processing
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Data Redundancy same piece of data could be duplicated inseveral places by several applications
Leads to data inconsistency and data integrity
Program-Data DependenceIt refers to the coupling of data storedin files and the specific programs required to update and maintainthose files such that changes in programs require changes to the data
Lack of flexibility - A traditional file system can deliver routinescheduled reports after extensive programming efforts, but it cannotdeliver ad hoc reports or respond to unanticipated informationrequirements in a timely fashion.
Poor Securitydifficult to enforce Lack of Data sharing and availability- Because pieces of information
in different files and different parts of the organization cannot berelated to one another, it is virtually impossible for information to beshared or accessed in a timely manner.
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Database Management Approach
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Consolidates data records into one database thatcan be accessed by many different applicationprograms.
Software interface between users or applicationprograms and databases
Data definition is stored once, separately fromapplication programs
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Database Management Approach
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The Database Approach (continued)
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Advantages of the Database Approach
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The Database Approach (continued)
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Advantages of the Database Approach (continued)
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The Database Approach (continued)
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Disadvantages of the Database Approach