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Managing Data Resources

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Title: Managing Data Resources


1
Managing Data Resources
Chapter 7
2
Outlines
  • Challenges to access information using
    traditional file management technologies.
  • Database management systems.
  • Managerial and organizational requirements for
    implementing a database environment successfully.

3
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

4
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

5
Organizing Data in a Traditional File Environment
The data hierarchy
Figure 7-1
6
Organizing Data in a Traditional File Environment
Entities and attributes
Figure 7-2
7
Organizing Data in a Traditional File Environment
Traditional file processing
Figure 7-3
8
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

9
Organizing Data in a Traditional File Environment
Problems with the Traditional File Environment
  • Data redundancy The presence of duplicate data
    in multiple data files so that the same data are
    stored in more than one place or location.
  • Waste storage resources
  • Data inconsistency the same attribute having
    different values (loose user confidence).

10
Organizing Data in a Traditional File Environment
Problems with the Traditional File Environment
  • Program-data dependence Program changes lead to
    data changes.
  • 2-digit versus 4-digit year
  • Sequence in a record
  • Delimited character

11
Organizing Data in a Traditional File Environment
Problems with the Traditional File Environment
  • Lack of flexibility
  • Data merge
  • Ad hoc reports
  • Poor security
  • Theft of data can occur in any department without
    the knowledge of managers
  • Lack of data-sharing and availability

12
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

13
The Database Approach to Data Management
The contemporary database environment
Figure 7-4
14
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

15
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

16
The Database Approach to Data Management
Sample data dictionary report
Figure 7-5
17
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

18
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 (the power of RDBMS)
  • Examples DB2, Oracle, MS SQL Server

19
The Database Approach to Data Management
The relational data model
Figure 7-6
20
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

21
The Database Approach to Data Management
The three basic operations of a relational DBMS
Figure 7-7
22
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

23
The Database Approach to Data Management
A hierarchical database for a human resources
system
Figure 7-8
24
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

25
The Database Approach to Data Management
The network data model
Figure 7-9
26
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

27
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

28
Creating a Database Environment
Designing Databases
  • Two Design Phases 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

29
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

30
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

31
Creating a Database Environment
An entity-relationship diagram
Figure 7-10
32
Creating a Database Environment
An unnormalized relation for ORDER
Figure 7-11
33
Creating a Database Environment
A normalized relation for ORDER
Figure 7-12
34
Creating a Database Environment
Distributing Databases
  • Distributed Database
  • Pros
  • Partitioned or replicated to more than one
    location
  • Increases service and responsiveness
  • Reduces vulnerability of single, massive central
    site
  • Cons
  • Depend on telecommunication lines
  • Pose security risks through distribution of
    sensitive data
  • Central data must be updated or justified with
    local data

35
Creating a Database Environment
Distributed databases
Figure 7-13
36
Creating a Database Environment
Key organizational elements in the database
environment
Figure 7-14
37
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

38
Creating a Database Environment
Management Requirements for Database Systems
  • Data Planning and Modeling Methodology
  • Enterprise-wide planning for data
  • Enterprise Analysis Identify key entities,
    attributes, and relationships that constitute the
    organizations data

39
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
  • Permit non-professional access to database
    through SQL
  • Devote more resources to end-user training

40
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

41
Database Trends
Multidimensional data model
Figure 7-15
42
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

43
Database Trends
Components of a data warehouse
Figure 7-16
44
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

45
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?

46
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

47
Database Trends
A hypermedia database
Figure 7-17
48
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

49
Database Trends
Linking internal databases to the Web
Figure 7-18
50
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

51
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?
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