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ch06.ppt

  1. 1. CHAPTER 6. MANAGING DATA RESOURCES
  2. 2. LEARNING OBJECTIVES <ul><li>COMPARE TRADITIONAL FILE ORGANIZATION & MANAGEMENT TECHNIQUES </li></ul><ul><li>EXPLAIN PROBLEMS OF TRADITIONAL FILE ENVIRONMENT </li></ul><ul><li>DESCRIBE HOW DATABASE MANAGEMENT SYSTEM ORGANIZES INFORMATION </li></ul><ul><li>* </li></ul>
  3. 3. LEARNING OBJECTIVES <ul><li>IDENTIFY TYPES OF DATABASE, PRINCIPLES OF DATABASE DESIGN </li></ul><ul><li>DISCUSS DATABASE TRENDS </li></ul><ul><li>ANALYZE MANAGERIAL, ORGANIZATIONAL REQUIREMENTS FOR CREATING DATABASE ENVIRONMENT </li></ul><ul><li>* </li></ul>
  4. 4. MANAGEMENT CHALLENGES <ul><li>TRADITIONAL DATA FILE ENVIRONMENT </li></ul><ul><li>DATABASE ENVIRONMENT </li></ul><ul><li>DESIGNING DATABASES </li></ul><ul><li>DATABASE TRENDS </li></ul><ul><li>MANAGEMENT REQUIREMENTS FOR DATABASE SYSTEMS </li></ul><ul><li>* </li></ul>
  5. 5. FILE ORGANIZATION <ul><li>BIT: Binary Digit (0,1; Y,N; On,Off) </li></ul><ul><li>BYTE: Combination of BITS which represent a CHARACTER </li></ul><ul><li>FIELD: Collection of BYTES which represent a DATUM or Fact </li></ul><ul><li>RECORD: Collection of FIELDS which reflect a TRANSACTION </li></ul><ul><li>* </li></ul>
  6. 6. FILE ORGANIZATION <ul><li>FILE: A Collection of Similar RECORDS </li></ul><ul><li>DATABASE: An Organization’s Electronic Library of FILES </li></ul><ul><li>* </li></ul>
  7. 7. FILE ORGANIZATION <ul><li>ENTITY: Person, Place, Thing, Event about Which Data Must be Kept </li></ul><ul><li>ATTRIBUTE: Description of a Particular ENTITY </li></ul><ul><li>KEY FIELD: Field Used to Retrieve, Update, Sort RECORD </li></ul><ul><li>* </li></ul>
  8. 8. KEY FIELD <ul><li>Field in Each Record </li></ul><ul><li>Uniquely Identifies THIS Record </li></ul><ul><li>For RETRIEVAL </li></ul><ul><li> UPDATING </li></ul><ul><li>SORTING </li></ul><ul><li>* </li></ul>
  9. 9. SEQUENTIAL VS. DIRECT FILE ORGANIZATION <ul><li>SEQUENTIAL: Tape Oriented; One File Follows Another; Follows Physical Sequence </li></ul><ul><li>DIRECT: Disk Oriented; Can be Accessed Without Regard to Physical Sequence </li></ul><ul><li>* </li></ul>
  10. 10. FILING METHODS <ul><li>INDEXED SEQUENTIAL ACCESS METHOD (ISAM) : </li></ul><ul><ul><li>EACH RECORD IDENTIFIED BY KEY </li></ul></ul><ul><ul><li>GROUPED IN BLOCKS AND CYLINDERS </li></ul></ul><ul><ul><li>KEYS IN INDEX </li></ul></ul><ul><li>VIRTUAL STORAGE ACCESS METHOD (VSAM) : </li></ul><ul><ul><li>MEMORY DIVIDED INTO AREAS & INTERVALS </li></ul></ul><ul><ul><li>DYNAMIC FILE SPACE </li></ul></ul><ul><li>VSAM WIDELY USED FOR RELATIONAL DATABASES </li></ul><ul><li>DIRECT FILE ACCESS METHOD </li></ul><ul><li>* </li></ul>
  11. 11. DIRECT FILE ACCESS METHOD <ul><li>EACH RECORD HAS KEY FIELD </li></ul><ul><li>KEY FIELD FED INTO TRANSFORM ALGORITHM </li></ul><ul><li>ALGORITHM GENERATES PHYSICAL STORAGE LOCATION OF RECORD (RECORD ADDRESS) </li></ul><ul><li>* </li></ul>
  12. 12. <ul><li>DATA REDUNDANCY </li></ul><ul><li>PROGRAM / DATA DEPENDENCY </li></ul><ul><li>LACK OF FLEXIBILITY </li></ul><ul><li>POOR SECURITY </li></ul><ul><li>LACK OF DATA SHARING & AVAILABILITY </li></ul><ul><li>* </li></ul>TRADITIONAL FILE ENVIRONMENT (FLAT FILE)
  13. 13. DATABASE <ul><li>ORGANIZATION’S ELECTRONIC LIBRARY </li></ul><ul><li>STORES & MANAGES DATA </li></ul><ul><li>IN A CONVENIENT FORM </li></ul><ul><li>* </li></ul>
  14. 14. DATABASE MANAGEMENT SYSTEM (DBMS) <ul><li>SOFTWARE TO CREATE & MAINTAIN DATA </li></ul><ul><li>ENABLES BUSINESS APPLICATIONS TO EXTRACT DATA </li></ul><ul><li>INDEPENDENT OF SPECIFIC COMPUTER PROGRAMS </li></ul><ul><li>* </li></ul>DBMS
  15. 15. COMPONENTS OF DBMS: <ul><li>DATA DEFINITION LANGUAGE: </li></ul><ul><ul><li>Defines data elements in database </li></ul></ul><ul><li>DATA MANIPULATION LANGUAGE: </li></ul><ul><ul><li>Manipulates data for applications </li></ul></ul><ul><li>DATA DICTIONARY: </li></ul><ul><ul><li>Formal definitions of all variables in database; controls variety of database contents </li></ul></ul><ul><li>* </li></ul>DBMS
  16. 16. STRUCTURED QUERY LANGUAGE (SQL) <ul><li>EMERGING STANDARD </li></ul><ul><li>DATA MANIPULATION LANGUAGE </li></ul><ul><li>FOR RELATIONAL DATABASES </li></ul><ul><li>* </li></ul>DBMS
  17. 17. TWO VIEWS OF DATA <ul><li>PHYSICAL VIEW: Where is data physically? </li></ul><ul><ul><li>DRIVE, DISK, SURFACE, TRACK, SECTOR (BLOCK), RECORD </li></ul></ul><ul><ul><li>TAPE, BLOCK, RECORD NUMBER (KEY) </li></ul></ul><ul><li>LOGICAL VIEW: What data is needed by application? </li></ul><ul><ul><li>SUCCESSION OF FACTS NEEDED BY APPLICATION </li></ul></ul><ul><ul><li>NAME, TYPE, LENGTH OF FIELD </li></ul></ul><ul><li>* </li></ul>BIT BYTE FIELD RECORD FILE DATABASE DBMS
  18. 18. RELATIONAL DATA MODEL <ul><li>DATA IN TABLE FORMAT </li></ul><ul><li>RELATION: TABLE </li></ul><ul><li>TUPLE: ROW (RECORD) IN TABLE </li></ul><ul><li>FIELD: COLUMN (ATTRIBUTE) IN TABLE </li></ul><ul><li>* </li></ul>
  19. 19. TYPES OR RELATIONS ONE-TO-ONE: STUDENT ID ONE-TO-MANY: CLASS STUDENT A STUDENT B STUDENT C MANY-TO-MANY: STUDENT A STUDENT B STUDENT C CLASS 1 CLASS 2
  20. 20. HIERARCHICAL DATA MODEL ROOT FIRST CHILD 2nd CHILD Ratings Salary Compensation Job Assignments Pension Insurance Health Benefits Employer
  21. 21. NETWORK DATA MODEL <ul><li>VARIATION OF HIERARCHICAL MODEL </li></ul><ul><li>USEFUL FOR MANY-TO-MANY RELATIONSHIPS </li></ul><ul><li>* </li></ul>NETWORK A NETWORK B NETWORK C NETWORK 1 NETWORK 2
  22. 22. OTHER SYSTEMS <ul><li>LEGACY SYSTEM: older system </li></ul><ul><li>OBJECT-ORIENTED DBMS: stores data & procedures as objects </li></ul><ul><li>OBJECT-RELATIONAL DBMS: hybrid </li></ul><ul><li>* </li></ul>
  23. 23. CREATING A DATABASE <ul><li>CONCEPTUAL DESIGN </li></ul><ul><li>PHYSICAL DESIGN </li></ul><ul><li>* </li></ul>
  24. 24. CREATING A DATABASE CONCEPTUAL DESIGN: <ul><li>ABSTRACT MODEL, BUSINESS PERSPECTIVE </li></ul><ul><li>HOW WILL DATA BE GROUPED? </li></ul><ul><li>RELATIONSHIPS AMONG ELEMENTS </li></ul><ul><li>ESTABLISH END-USER NEEDS </li></ul><ul><li>* </li></ul>
  25. 25. CREATING A DATABASE PHYSICAL DESIGN: <ul><li>DETAILED MODEL BY DATABASE SPECIALISTS </li></ul><ul><li>ENTITY-RELATIONSHIP DIAGRAM </li></ul><ul><li>NORMALIZATION </li></ul><ul><li>HARDWARE / SOFTWARE SPECIFIC </li></ul><ul><li>* </li></ul>
  26. 26. ENTITY- RELATIONSHIP DIAGRAM 1 1 M 1 ORDER CAN HAVE PART SUPPLIER CAN HAVE ORDER: #, DATE, PART #, QUANTITY PART: #, DESCRIPTION, UNIT PRICE, SUPPLIER # SUPPLIER: #, NAME, ADDRESS
  27. 27. NORMALIZATION <ul><li>PROCESS OF CREATING SMALL DATA STRUCTURES FROM COMPLEX GROUPS OF DATA </li></ul><ul><li>EXAMPLES: </li></ul><ul><li>ACCOUNTS RECEIVABLE </li></ul><ul><li>PERSONNEL RECORDS </li></ul><ul><li>PAYROLL </li></ul><ul><li>* </li></ul>
  28. 28. DISTRIBUTED DATABASES <ul><li>PARTITIONED: remote CPUs (connected to host) have files unique to that site, e.g., records on local customers </li></ul><ul><li>DUPLICATE: each remote CPU has copies of common files, e.g., layouts for standard reports and forms </li></ul><ul><li>* </li></ul>
  29. 29. DATABASE TRENDS <ul><li>MULTIDIMENSIONAL DATA ANALYSIS: 3D (or higher) groupings to store complex data </li></ul><ul><li>HYPERMEDIA: Nodes contain text, graphics, sound, video, programs. organizes data as nodes. </li></ul><ul><li>* </li></ul>
  30. 30. DATABASE TRENDS <ul><li>DATA WAREHOUSE: Organization’s electronic library stores consolidated current & historic data for management reporting & analysis </li></ul><ul><li>DATA MART: Small data warehouse for special function, e.G., Focused marketing based on customer info </li></ul><ul><li>* </li></ul>
  31. 31. COMPONENTS OF DATA WAREHOUSE
  32. 32. DATABASE TRENDS <ul><li>ON-LINE ANALYTICAL PROCESSING (OLAP): ability to manipulate, analyze large volumes of data from multiple perspectives </li></ul><ul><li>LINKING DATABASES TO THE WEB </li></ul><ul><li>* </li></ul>
  33. 33. ELEMENTS OF DATABASE ENVIRONMENT DATABASE MANAGEMENT SYSTEM DATA ADMINISTRATION DATABASE TECHNOLOGY & MANAGEMENT USERS DATA PLANNING & MODELING METHODOLOGY
  34. 34. DATABASE ADMINISTRATION <ul><li>DEFINES & ORGANIZES DATABASE STRUCTURE AND CONTENT </li></ul><ul><li>DEVELOPS SECURITY PROCEDURES </li></ul><ul><li>DEVELOPS DATABASE DOCUMENTATION </li></ul><ul><li>MAINTAINS DBMS </li></ul><ul><li>* </li></ul>
  35. 35. Connect to the INTERNET Laudon/Laudon Web site: http://www. prenhall .com/ laudon Additional Internet Resources related to this chapter: http://www.oracle.com news:comp.databases news:comp.databases.theory http://w3.one.net/~ jhoffman / sqltut . htm http://www. compapp . dcu . ie /databases/welcome.html http://www. acm .org/ sigmod http://www. dwinfocenter .org/ http://138.87.1.4/ DataWarehouse / whselead .html © 2001 Laudon & Laudon, Essentials of Management Information Systems 4/e
  36. 36. CHAPTER 6. MANAGING DATA RESOURCES

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