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Organizing Data and Information C H A P T E R


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  • 1. Organizing Data and Information 5 C H A P T E R
  • 2. The Hierarchy of Data
    • Database
      • Collection of data organized to meet users’ needs
    • Database management system (DBMS)
      • Software consisting of a group of programs that manipulate the database and provide an interface between the database and the application programs
  • 3. The Hierarchy of Data
    • Data is generally organized in a hierarchy that begins with the smallest piece of data (a bit) and progresses through the hierarchy to a database.
  • 4. The Hierarchy of Data
    • Character
      • Basic building block of information, represented by a byte (0,1)
    • Field
      • A name, number, or combination of characters that describes an aspect of a business activity
  • 5. The Hierarchy of Data
    • Record
      • Collection of related fields
    • File
      • Collection of related records
    • Database
      • Collection of integrated and related files
  • 6. Data Entities, Attributes, and Keys
    • Entity
      • Generalized class of people, places, or things for which data is collected, stored, and maintained
    • Attribute
      • Characteristic of an entity
    • Data item
      • Specific value of an attribute
  • 7. Data Entities, Attributes, and Keys
    • Key
      • A field or set of fields in a record that is used to identify the record
      • Primary key
        • A field or set of fields that uniquely identifies the record
      • Secondary key
        • A field in a record that does not uniquely identify the record
  • 8. Keys and Attributes Entities (records) Key field Attributes
  • 9. The Traditional Approach to Data Management [Figure 5.3]
  • 10. Flaws in the Traditional Approach
    • Data redundancy
      • Duplication of data in separate files
    • Data integrity
      • The degree to which the data in any one file is accurate
    • Program-data dependence
      • Potential for incompatible programs and data between applications
  • 11. The Database Approach to Data Management
    • Data management in which a pool of related data is shared by multiple application programs
    • Rather than having separate data files, each application uses a collection of data that are either joined or related in the database.
  • 12. The Database Approach to Data Management [Figure 5.4]
  • 13. Advantages of the Database Approach
    • Improved strategic use of corporate data
    • Reduced data redundancy
    • Improved data integrity
    • Easier modification and updating
    • Data and program independence
  • 14. Advantages of the Database Approach
    • Better access to data and information
    • Standardization of data access
    • A framework for program development
    • Better overall protection of the data
    • Shared data and information resources
  • 15. Disadvantages of the Database Approach
    • Relatively high cost of purchasing and operating a DBMS in a mainframe operating environment
    • Specialized staff
    • Increased vulnerability
  • 16. Database Considerations
    • Content
      • What data is to be collected at what cost?
    • Access
      • What data is to be provided to which users when appropriate?
  • 17. Database Considerations
    • Logical structure
      • How is the data to be arranged so that it makes sense to a given user?
    • Physical organization
      • Where is the data to be physically located?
  • 18. Types of Database Design
    • Logical design
      • An abstract model of how the database should be structured and arranged to meet an organization’s information needs
    • Physical design
      • A model of how the data will be organized and located within the database
  • 19. Data Modeling and Entity-Relationship Diagrams
    • Data model
      • A map or diagram of entities and their relationships
    • Enterprise data modeling
      • Data modeling done at the level of the entire organization
  • 20. Entity-Relationship (ER) Diagrams
    • Diagrams that use basic graphical diagrams to show the organization of and relationships between data
    • Relationships include:
      • One-to-one (1:1)
      • One-to-many (1:N)
      • Many-to-many (N:M)
  • 21. An Entity-Relationship Diagram [Figure 5.5] An ER diagram for a customer ordering database Entities Relationship Attributes
  • 22. Database Models
    • Hierarchical (tree) models
    • Network models
    • Relational models
  • 23. Hierarchical Database Model
    • A model in which the data is organized in a top-down or inverted tree-like structure
    • [Figure 5.6]
  • 24. Network Models
    • An extension of the hierarchical model, in which a member may have many owners
    • [Figure 5.7]
  • 25. Relational Models
    • Data organized in tabular format (rows and columns)
      • Relations: Two-dimensional tables into which data elements are placed
      • Tuple: Each row of a table
      • Attributes: Columns of the table
      • Domain: Values for attributes or columns
  • 26. Relational Models [Figure 5.8]
  • 27. Data Manipulations
    • Selecting
      • Eliminating rows according to certain criteria
    • Projecting
      • Eliminating columns in a table
  • 28. Data Manipulations
    • Joining
      • Combining two or more tables
    • Linking
      • Joining tables that share at least one common data element
  • 29. Data Analysis and Normalization
    • Data analysis
      • Evaluation of data to uncover problems with the content of a database
    • Anomalies
      • Problems and irregularities in data
    • Normalization
      • Removing anomalies from a database
  • 30. Comparison of Database Models
    • Hierarchical model
      • Primary advantage: processing efficiency
    • Network model
      • More flexible than hierarchical models in terms of organizing data
    • Relational database model
      • Easier to control, more flexible, and more intuitive; by far the most widely used
  • 31. Database Characteristics
    • Amount
      • Database size depends on the number of records or files it contains
    • Volatility
      • A measure of the changes typically required in a given period of time
    • Immediacy
      • A measure of how rapidly changes must be made to data
  • 32. Database Management Systems
    • Group of programs used as an interface between a database and application programs or a database and the user
    • Classified by the type of database model they support
      • Hierarchical
      • Network
      • Relational
  • 33. Storing and Retrieving Data
    • Logical access path
      • Application requests data from the DBMS
    • Physical access path
      • DBMS accesses a storage device to retrieve the data
    • [Figure 5.14]
  • 34. Data Control
    • Concurrency control
      • Locks out simultaneous access to a record that is being updated or used by another program
    • Schema
      • The logical and physical structure of the data and relationships among the data in the database
  • 35. Providing a User View
    • User view
      • Portion of the database a user can access
    • Subschema
      • A file that contains a description of a subset of the database and identifies which users can perform modification on the data items in that subset
      • Developed to create different views
  • 36. The Use of Schemas and Subschemas [Figure 5.15]
  • 37. Creating and Modifying the Database
    • Data definition language (DDL)
      • Collection of instructions and commands used to define and describe data and data relationships in a specific database
    • [Figure 5.16]
  • 38. Creating and Modifying the Database
    • Data dictionary
      • A detailed description of all data used in the database
    [Figure 5.17]
  • 39. Data Dictionary
    • Provides a standard definition of terms and data elements
    • Assists programmers in designing and writing programs
    • Simplifies database modifications
  • 40. Data Dictionary
    • Helps achieve advantages of the database approach
      • Reduced data redundancy
      • Increased data reliability
      • Faster program development
      • Easier modification of data and information
  • 41. Manipulating Data and Generating Reports
    • Data Manipulation Language (DML)
      • Contains the commands used to manipulate the database
      • Allows managers and other database users to access, modify, and make queries about data contained in the database to generate reports
  • 42. Structured Query Language (SQL)
    • A standardized data manipulation language that has become an integral part of most relational database packages
  • 43. Selecting a Database Management System
    • Begins by analyzing database needs and characteristics
      • Performance
      • Integration
      • Features
      • The vendor
      • Cost
  • 44. Emerging Database Trends
    • Distributed databases
      • Actual data may be spread across several smaller databases connected via telecommunications devices
    • Replicated database
      • Holds a duplicate set of frequently used data
  • 45. Distributed Database HCIA p223 HCIA, Inc. uses a distributed database to provide up-to-date information to their customers.
  • 46. Data Warehouse
    • A relational database management system designed specifically to support management decision making
    • [Figure 5.21]
  • 47. Data Warehouse
    • Data mart
      • Subset of a data warehouse
      • Brings the data warehouse concept to small and medium-size businesses
    • On-line analytical processing (OLAP)
      • Consists of programs used to store and deliver data warehouse information
    • Data mining
      • Automated discovery of patterns and relationships in a data warehouse
  • 48. Open Database Connectivity (ODBC)
    • Standards that help ensure that specific software can be used with any ODBC-compliant database
    • [Figure 5.22]
  • 49. Object-Oriented Databases
    • Databases that store data as objects, which contain both the data and the processing instructions needed to complete the database transaction
    • [Table 5.6]
  • 50. Image, Hypertext, and Hypermedia Databases
    • Image databases
      • Store data in the form of images
    • Hypertext databases
      • Allow users to search and manipulate alphanumeric data in an unstructured way
    • Hypermedia databases
      • Allow businesses to search and manipulate multimedia forms of data
  • 51. Spatial Data Technology
    • Involves the use of an object-relational database
    • Stores and accesses data according to the locations it describes
    • Permits spatial queries and analysis
  • 52. Aspects of Database Administration
    • Overall design and coordination of the database
    • Development and maintenance of schemas and subschemas
    • Development and maintenance of the data dictionary
    • Implementation of the DBMS
  • 53. Aspects of Database Administration
    • System and user documentation
    • User support and training
    • Overall operation of the DBMS
    • Testing and maintaining the DBMS
    • Establishing emergency or failure-recovery procedures
  • 54. Database Use, Policies, and Security
    • What data should users have direct access to?
    • Under what circumstances can data be transferred from a PC or small computer system to the large mainframe system (uploading)?
  • 55. Database Use, Policies, and Security
    • Under what circumstances can data be transferred from a mainframe system to PCs or small computer system (downloading)?
    • What procedures are needed to guarantee proper database use?