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Chapter 7. Managing Data Resources. Objectives. Why do businesses have trouble finding the information they need in their information systems? How does a database management system help businesses improve the organization of their information?. Objectives.

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objectives
Objectives
  • Why do businesses have trouble finding the information they need in their information systems?
  • How does a database management system help businesses improve the organization of their information?
objectives1
Objectives
  • How do the principal types of database models affect the way businesses can access and use information?
  • What are the managerial and organizational requirements of a database environment?
  • What new tools and technologies can make databases more accessible and useful?
management challenges
Management Challenges
  • Organizational obstacles to a database environment
  • Cost/benefit considerations
organizing data in a traditional file environment
Organizing Data in a Traditional File Environment

File Organization Terms and Concepts

  • Bit: Smallest unit of data; binary digit (0,1)
  • Byte: Group of bits that represents a single character
  • 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 environment1
Organizing Data in a Traditional File Environment

File Organization Terms and Concepts

  • Database: Group of related files
  • Entity: Person, place, thing, or event about which information must be kept
  • Attribute: A piece of information describing a particular entity
  • Key field: Field that uniquely identifies every record in a file
organizing data in a traditional file environment3
Organizing Data in a Traditional File Environment

Entities and attributes

Figure 7-2

organizing data in a traditional file environment4
Organizing Data in a Traditional File Environment

Problems with the Traditional File Environment

  • Data redundancy
  • Program-data dependence
  • Lack of flexibility
  • Poor security
  • Lack of data-sharing and availability
organizing data in a traditional file environment5
Organizing Data in a Traditional File Environment

Traditional file processing

Figure 7-3

the database approach to data management
The Database Approach to Data Management

Database Management Systems

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 management1
The Database Approach to Data Management

The contemporary database environment

Figure 7-4

the database approach to data management2
The Database Approach to Data Management

Database Management Systems

Database Management System (DBMS)

  • Creates and maintains databases
  • Eliminates requirement for data definition statements
  • Acts as interface between application programs and physical data files
  • Separates logical and physical views of data
the database approach to data management3
The Database Approach to Data Management

Database Management Systems

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, organizing definitions of data elements and data characteristics
the database approach to data management4
The Database Approach to Data Management

Sample data dictionary report

Figure 7-5

the database approach to data management5
The Database Approach to Data Management

Database Management Systems

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, and security
the database approach to data management6
The Database Approach to Data Management

Types of Databases

Relational DBMS

  • Represents data as two-dimensional tables called relations
  • Relates data across tables based on common data element
  • Examples: DB2, Oracle, MS SQL Server
the database approach to data management7
The Database Approach to Data Management

The relational data model

Figure 7-6

the database approach to data management8
The Database Approach to Data Management

Types of Databases

Three Basic Operations in a Relational Database

  • Select: Creates subset of rows that meet specific criteria
  • Join: Combines relational tables to provide users with information
  • Project: Enables users to create new tables containing only relevant information
the database approach to data management9
The Database Approach to Data Management

The three basic operations of a relational DBMS

Figure 7-7

the database approach to data management10
The Database Approach to Data Management

Types of Databases

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 management11
The Database Approach to Data Management

A hierarchical database for a human resources system

Figure 7-8

the database approach to data management12
The Database Approach to Data Management

Types of Databases

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 many students
the database approach to data management13
The Database Approach to Data Management

The network data model

Figure 7-9

the database approach to data management14
The Database Approach to Data Management

Types of Databases

Disadvantages of Hierarchical and

Network DBMS

  • Outdated
  • Less flexible compared to RDBMS
  • Lack support for ad-hoc and English language-like queries
the database approach to data management15
The Database Approach to Data Management

Types of Databases

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
creating a database environment
Creating a Database Environment

Designing Databases

Two Design Exercises in Creating Database

  • Conceptual (logical) design: Abstract model of database from business perspective
  • Physical design: How the database is actually arranged on direct access storage devices
creating a database environment1
Creating a Database Environment

Designing Databases

Conceptual Database Design

  • Identifies relationships between data elements
  • Identifies most efficient way to group data elements
  • Identifies redundant data elements
  • Identifies grouping of data elements needed for specific applications
creating a database environment2
Creating a Database Environment

Designing Databases

Entity-Relationship Diagram

A methodology for documenting databases that illustrates the relationship between various elements in the database

Normalization

The process of creating small, stable, and adaptive data structures from complex groups of data when designing a relational database

creating a database environment3
Creating a Database Environment

An entity-relationship diagram

Figure 7-10

creating a database environment4
Creating a Database Environment

An unnormalized relation for ORDER

Figure 7-11

creating a database environment5
Creating a Database Environment

A normalized relation for ORDER

Figure 7-12

creating a database environment6
Creating a Database Environment

Distributing Databases

Distributed Database

  • Partitioned or replicated to more than one location
  • Increases service and responsiveness
  • Reduces vulnerability of single, massive central site
  • Depend on telecommunication lines
  • Pose security risks through distribution of sensitive data
  • Central data must be updated or justified with local data
creating a database environment7
Creating a Database Environment

Distributed databases

Figure 7-13

creating a database environment8
Creating a Database Environment

Key organizational elements in the database environment

Figure 7-14

creating a database environment9
Creating a Database Environment

Management Requirements for Database Systems

Data Administration

  • Develop information policy
  • Define information requirements
  • Plan for data
  • Oversee logical database design and database dictionary development
  • Monitor use of information
creating a database environment10
Creating a Database Environment

Management Requirements for Database Systems

Data Planning and Modeling Methodology

  • Enterprise-wide planning for data
  • Identify key entities, attributes, and relationships that constitute the organization’s data
creating a database environment11
Creating a Database Environment

Management Requirements for Database Systems

Database Technology, Management,

and Users

  • Databases require DBMS software and staff
  • Database design group defines and organizes structure and content of database
  • Database administration: establish physical database, logical relations, access rules
database trends
Database Trends

Multidimensional Data Analysis

Online Analytical Processing (OLAP)

  • Multidimensional data analysis
  • Enables users to view the same data in different ways using multiple dimensions
  • Each aspect of information – product, price, region – represents a different dimension
database trends1
Database Trends

Multidimensional data model

Figure 7-15

database trends2
Database Trends

Data Warehouses and Datamining

  • Data warehouse: Stores current and historical data for reporting, analysis
  • Data mart: Subset of data warehouse with summary of data for specific users
  • Datamining: Techniques to find hidden patterns, relationships in large pools of data to infer rules for predicting future trends
database trends3
Database Trends

Components of a data warehouse

Figure 7-16

database trends4
Database Trends

Data Warehouses and Datamining

Benefits of Data Warehouses

  • Improved information and accessibility
  • Ability to model and remodel data
  • Enable access to data without affecting performance of underlying operational legacy systems
database trends5
Database Trends

Window on Management

Data Reveal New Sales Opportunities

  • How did the use of data warehouses and datamining help management at these companies make better decisions?
  • What value do these systems provide?
database trends6
Database Trends

Data Warehouses and Datamining

Hypermedia database

  • Organizes data as network of nodes
  • Links nodes in pattern specified by user
  • Supports text, graphic, sound, video and executable programs
database trends7
Database Trends

A hypermedia database

Figure 7-17

database trends8
Database Trends

Databases and the Web

Linking Internal Databases to the Web

  • Database server:
    • Hosts DBMS
    • Receives SQL requests
    • Provides required data
  • Middleware:
    • Works between Web server and DBMS to take requests
    • Handles connectivity to database
    • Can be application server or CGI scripts
database trends9
Database Trends

Linking internal databases to the Web

Figure 7-18

database trends10
Database Trends

Databases and the Web

Advantages to Web Access to Databases

  • Browser software easy to use; little training
  • Web interface requires no changes to internal database
  • Costs less than custom interfaces
database trends11
Database Trends

Window on Technology

Web Access for Royal Bank Statements

Pays Off

  • What are the business benefits of providing a Web interface for the Bankbook Reconstruct application?
  • What value does this application provide the company and its customers?
chapter 7 case study
Chapter 7 Case Study

Database Woes Plague Homeland Security and Law Enforcement

  • Briefly summarize why it is important to connect much of the data in many of the federal, state, and local information systems.
  • Describe the major data management problems in bringing these data together.
  • Describe the management, organization, and technology issues that need to be addressed to make these data easily available to those who need it.
chapter 7 case study1
Chapter 7 Case Study

Database Woes Plague Homeland Security and Law Enforcement

  • Suppose you are a consultant to the federal government. Based on what you have read in this chapter, suggest and describe three approaches you might recommend for making this massive amount of data easily and quickly available when needed.