Systems Chapter 2

Card Set Information

Systems Chapter 2
2011-01-27 23:00:07

Chapter 2 Terms
Show Answers:

  1. Data
    Known facts that can be recorded and preserved

    -Includes text, graphics, images, music, and video
  2. Information
    the processed data presented in a form suitable form suitable for human interpretation

    -the same data can be processed in a variety of ways to generate different kinds of information
  3. Metadata
    data providing info about one f more other pieces of data

    • concept that applies mainly to electronically archived or presented data and is used to describe the:
    • -data definition
    • -data structure
    • -administration of data files with all contents in context to ease the use of the captured and archived data for further use

    used to standardize the storage and retrieval of data elements in a data warehouse; defintes elements of the warehouse and how they work
  4. Data Warehouse
    houses standardized, structured, consistent, integrated, correct, clensed and timely data, extracted from various operational systems in an organization
  5. File Based approach
    stores, manipulates, retrieves data from large flat files
  6. Flat File
    typically organized sequentially in a fixed format

    -requires each application that uses the file to include the info and meaning about the structure of the data in the file
  7. Limitations of flat files
    • -inefficient for handling queries
    • -duplication of data
    • -data dependency; changes in data require re-programming
    • -slow development, high maintenance and fixed queries
  8. Database Management System (DBMS)
    • piece of software that allows a user to define, create, and manage access to a database
    • -decouples application programs from data
    • -data duplication limited; all in one location
  9. Database System
    • combination of:
    • -customer requirements
    • -application programs addressing the customer requirements
    • -a DBMS
    • -a database holding the data
  10. Four components in any database system
    Users, database application, DBMS, database
  11. Database Applications
    • computer programs that allow users to manipulate the data in a DBMS through user-friendly interface
    • -Personal: single user
    • -Departmental: hundreds of users over a network
    • -Enterprise: extensions of departmental applications
    • -Internet: largest form of info sharing
  12. Properties of a DMBS
    -Data independence: segregates program and data

    -Concurrency Control: handle multiple transactions

    -Recovery Services: recovers better than flat files

    -Utility services: performs initialization and maintenance operations
  13. Schema
    structure used to organize and represent our perspective or understanding of a system or a behavior
  14. Schema Levels
    • 1st: Internal Level
    • 2nd: Conceptual Level
    • 3rd: External Level
  15. Data Model
    collection of concepts for describing data, its relationships, and its constraints

    • -clearer more accurate description of data
    • -standard platform enables database designers and end-users to communicate

    • Three variables:
    • -object-based models (conceptual)
    • -record-based models (external)
    • -physical data models (internal)
  16. Object-based data models
    use entities, attributes, and relationships to present information

    • Examples:
    • -entity-relationship
    • -functional data
    • -object oriented
  17. Entity
    • a living or non-living object in the real world
    • -person, place, event
  18. Attribute
    • property of an entity
    • -name, address of a person
  19. Relationship
    association between entities
  20. Entity-Relationship model
    • describes data in for of E-R diagram
    • -entities=rectangles
    • -relationships=diamonds
    • -attributes=ovals
  21. Record-based data model
    used records to present data

    record: structure that contains a fixed number of fields to hold a piece of information

    • Three types:
    • -relational data models
    • -network data models
    • -hierarchical data models