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8/14/2019 Bagian 1 Managing Data Resources
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Managing Data Resources
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Objectives
Definition of terms
Explain growth and importance of databases
Name limitations of conventional file processing
Identify categories of databases
Explain advantages of databases
Identify costs and risks of databases
List components of database environment
Describe evolution of database systems
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Bit: Smallest unit of data; binary digit (0,1)
Byte: Group of bits that represents a singlecharacter
Field: Group of words or complete number
Record: Group of related fields
File: Group of records of the same type
Organizing Data in a Traditional File Environment
File Organization Terms and Concepts
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Database: Group of related files
Entity: Person, place, thing, or event about which
information must be kept
Attribute: A piece of information describing aparticular entity
Key field: Field that uniquely identifies everyrecord in a file
Organizing Data in a Traditional File Environment
File Organization Terms and Concepts
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Organizing Data in a Traditional File Environment
The data hierarchy
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Organizing Data in a Traditional File Environment
Entities and attributes
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Organizing Data in a Traditional File Environment
Traditional file processing
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Problems with Data Dependency
Each application programmer must maintain theirown data
Each application program needs to include codefor the metadata of each file
Each application program must have its ownprocessing routines for reading, inserting, updatingand 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:
When data changes in one file, could cause
inconsistencies Compromisesdata integrity
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Data redundancyDifferent systems/programs have separate copies of the same data
Program-data dependenceAll programs maintain metadata for each file they use
Lack of flexibilityProgrammers must design their own file formats
Poor security, lack of data-sharing and availabilityNo centralized control of data
Excessive Program Maintenance80% of of information systems budget
Organizing Data in a Traditional File Environment
Problems with the Traditional File Environment
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Database
Collection of centralized data
Controls redundant data
Data stored so as to appear to users in one location
Services multiple application
The Database Approach to Data Management
Database Management Systems
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Definitions
Database: organized collection of logically related
data
Data: stored representations of meaningful objects
and events Structured: numbers, text, dates
Unstructured: images, video, documents
Information: data processed to increase knowledge inthe person using the data
Metadata: data that describes the properties and
context of user data
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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
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Metadata :Descriptions of the properties or
characteristics of the data, including data types, field
sizes, allowable values, and data context
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The Database Approach to Data Management
The contemporary database environment
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Database Management System (DBMS)
A software system that is used to create, maintain,
and provide controlled access to user databases
Creates and maintains databases
Eliminates requirement for data definition
statements
Acts as interface between application programsand physical data files
Separates logical and physical views of data
The Database Approach to Data Management
Database Management Systems
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Three Components to a DBMS
Data definition language: Formal language
programmers use to specify structure of database Data manipulation language: For extracting data
from database, e.g. SQL
Data dictionary: Tool for storing, organizingdefinitions of data elements and datacharacteristics
The Database Approach to Data Management
Database Management Systems
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The Database Approach to Data Management
Sample data dictionary report
Figure 7-5
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How a DBMS Solves Problems of a
Traditional File Environment
Reduces data redundancy Eliminates data inconsistency
Uncouples programs from data
Increases access and availability of data
Allows central management of data, data use, andsecurity
The Database Approach to Data Management
Database Management Systems
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Advantages of the Database Approach
Program-data independence
Minimal data redundancy
Improved data consistency
Improved data sharing
Increased productivity of application development
Enforcement of standards
Improved data quality
Improved data accessibility and responsiveness
Reduced program maintenance
Improved decision support
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Cost and Risk 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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Components of the
Database Environment
CASE Tools computer-aided software engineering
Repository centralized storehouse of metadata
Database Management System (DBMS) software for managingthe database
Database storehouse of the data
Application Programs software using the data
User Interface text and graphical displays to users
Data Administrators personnel responsible for maintaining the
database System Developers personnel responsible for designing databases
and software
End Users people who use the applications and databases
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Components of the
Database Environment
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Evolution of DB Systems
Flat files - 1960s - 1980s
Hierarchical 1970s - 1990s
Network 1970s - 1990s
Relational 1980s - present
Object-oriented 1990s - present
Object-relational 1990s - present
Data warehousing 1980s - present
Web-enabled 1990s present
Data mining 2000s - present
Evolution of Database Systems
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The Database Approach to Data Management
The three basic operations of a relational DBMS
Figure 7-7
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Hierarchical DBMS
Older system presenting data in tree-like structure
Models one-to-many parent-child relationships
Found in large legacy systems requiring intensive high-
volume transactions: Banks; insurance companies
Examples: IBMs IMS
The Database Approach to Data Management
Types of Databases
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The Database Approach to Data Management
A hierarchical database for a human resources system
Figure 7-8
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Network DBMS
Older logical database model
Models many-to-many parent-child relationships
Example: Student course relationship: Each
student has many courses; each course has manystudents
The Database Approach to Data Management
Types of Databases
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The Database Approach to Data Management
The network data model
Figure 7-9
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Relational DBMS
Represents data as two-dimensional tables calledrelations
Relates data across tables based on common data
element Examples: DB2, Oracle, MS SQL Server
The Database Approach to Data Management
Types of Databases
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The Database Approach to Data Management
The relational data model
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Three Basic Operations in a RelationalDatabase
Select: Creates subset of rows that meet specificcriteria
Join: Combines relational tables to provide userswith information
Project: Enables users to create new tablescontaining only relevant information
The Database Approach to Data Management
Types of Databases
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Object-Oriented Databases (OODBMS)
Stores data and procedures as objects
Better able to handle graphics and recursive data
Data models more flexible
Slower than RDBMS
Hybrid: object-relational DBMS
The Database Approach to Data Management
Types of Databases
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Data Mining at Fingerhut Inc.Fingerhut published about 25 different catalogs, but shipped onlythe general merchandise catalog monthly and tracked customersbuying patterns and behaviors. If a customer bought cookware,first Fingerhut would follow up with specialized
Cooks Bookand More Houseware & cooking suppliescatalogs.Then telemarketers would call to follow up with new products.
Through customer data mining Fingerhut found that customers whorecently changed their residence were likely to triple their purchasingin the 12 weeks after their move, with a peak in buying in the first fourweeks. Their selections often followed a pattern new furniture,telecommunications equipment, and decorations but seldom jewelry orhome electronics. The company used this discovery to tailor a new"mover's catalog" to entice customers who recently moved.