Lecture 04 data resource management


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Lecture 04 data resource management

  1. 1. DATA RESOURCE MANAGEMENT Presented by: Dr. Akhlas Ahmed Lecture # 04 Preston University
  2. 2. File Organization: Terms & Concept  Binary: means composed of two pieces or two parts and may refer to: Mathematics: Binary number, a representation for numbers using only two digits (0 and 1) Binary relation, a mathematical relation involving two elements Binary function, a function in mathematics that takes two arguments Computing Binary file, composed of something other than human-readable text Executable, a type of binary file that contains machine code for the computer to execute Binary code, the digital representation of text and data
  3. 3. File Organization: Terms & Concept Multiples of bits Decimal Value 1000 10002 10003 10004 10005 10006 10007 10008 Value 1024 10242 10243 10244 10245 10246 10247 8 Metric kbit Mbit Gbit Tbit Pbit Ebit Zbit Ybit Kbit Mbit Gbit - kilobit megabit gigabit terabit petabit exabit zettabit yottabit Binary JEDEC kilobit megabit gigabit - Kibit Mibit Gibit Tibit Pibit Eibit Zibit IEC kibibit mebibit gibibit tebibit pebibit exbibit zebibit
  4. 4. File Organization: Terms & Concept •    Bit: A bit is the basic unit of information in computing and digital communications. A bit can have only one of two values, and may therefore be physically implemented with a twostate device. The most common representation of these values are 0and1. The term bit is a contraction of binary digit. Smallest unit of data; binary digit (0,1) Byte: Group of bits that represents a single character Field: Group of words or a complete number
  5. 5. File Organization: Terms & Concept  Record: Group of related fields  File: Group of records of same type  Database: Group of related files
  6. 6. Data Hierarchy: in a Computer System Figure 7-1
  7. 7. File Organization: Terms & Concept  Entity: Person, place, thing, event about which information is maintained  Attribute: Description of a particular entity  Key field: Identifier field used to retrieve, update, sort a record
  9. 9. Problems with the Traditional File Environment  Data redundancy Data redundancy occurs in database systems which have a field that is repeated in two or more tables. o Program-Data dependence A Flow dependency, also known as a data dependency or true dependency or read-after-write (RAW), occurs when an instruction depends on the result of a previous instruction: 1. A = 3 2. B = A 3. C = B    Lack of flexibility Poor security Lack of data-sharing and availability
  10. 10. Traditional File Processing Figure 7-3
  11. 11. 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
  12. 12. The Contemporary Database Environment
  13. 13. Components of DBMS • Data definition language: Specifies content and structure of database and defines each data element • Data manipulation language: Manipulates data in a database • Data dictionary: Stores definitions of data elements, and data characteristics
  14. 14. Sample Data Dictionary Report Figure 7-5
  15. 15. Types of Databases • Relational DBMS • Hierarchical and Network DBMS • Object-Oriented Databases
  16. 16. 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
  17. 17. Relational Data Model Figure 7-6
  18. 18. 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
  19. 19. Three Basic Operations in a Relational Database Figure 7-7
  20. 20. Hierarchical and Network DBMS Hierarchical DBMS • Organizes data in a tree-like structure • Supports one-to-many parent-child relationships • Prevalent in large legacy systems
  21. 21. Hierarchical DBMS Figure 7-8
  22. 22. Hierarchical and Network DBMS Network DBMS • Depicts data logically as many-to-many relationships
  23. 23. Network DBMS Figure 7-9
  24. 24. Hierarchical and Network DBMS Disadvantages  Outdated  Less flexible compared to RDBMS  Lack support for ad-hoc and English language-like queries
  25. 25. Object-Oriented Databases  Object-oriented DBMS: Stores data and procedures as objects that can be retrieved and shared automatically  Object-relational DBMS: Provides capabilities of both object-oriented and relational DBMS
  26. 26. Querying Databases: Elements of SQL Basic SQL Commands  SELECT:  FROM: Specifies columns Identifies tables or views  WHERE: Specifies conditions
  27. 27. Results of SELECT Statement
  28. 28. Results of Conditional Selection 137 150 Door latch Door seal 22.50 6.00
  29. 29. Projection from Joining PART and SUPPLIER Tables
  30. 30. Designing Databases  Conceptual design: Abstract model of database from a business perspective  Physical design: Detailed description of business information needs
  31. 31. Designing Databases  Entity-relationship diagram: Methodology for documenting databases illustrating relationships between database entities  Normalization: Process of creating small stable data structures from complex groups of data
  34. 34. CREATING A DATABASE ENVIRONMENT An Normalized Relation of ORDER Figure 7-15
  35. 35. Distributing Databases Centralized database  Used by single central processor or multiple processors in client/server network
  36. 36. Distributing Databases Distributed database  Stored in more than one physical location  Partitioned database  Duplicated database
  37. 37. Distributing Databases Figure 7-16
  38. 38. Management Requirements for Database Systems Key elements in a database environment:  Data Administration  Data Planning and Modeling Methodology  Database Technology and Management  Users
  39. 39. Management Requirements for Database Systems Figure 7-17
  40. 40. Multidimensional Data Analysis On-line analytical processing (OLAP)  Multidimensional data analysis  Supports manipulation and analysis of large volumes of data from multiple dimensions/perspectives
  41. 41. Multidimensional Data Model Figure 7-18
  42. 42. Data Warehousing and Datamining Data warehouse  Supports reporting and query tools  Stores current and historical data  Consolidates data for management analysis and decision making
  43. 43. Components of Data Warehouse Figure 7-19
  44. 44. Data Warehouse and data mining Data mart  Subset of data warehouse  Contains summarized or highly focused portion of data for a specified function or group of users
  45. 45. Data Warehouse and data mining Datamining  Tools for analyzing large pools of data  Find hidden patterns and infer rules to predict trends
  46. 46. Benefits of Data Warehouse  Improved and easy accessibility to information  Ability to model and remodel the data
  47. 47. Database and the web Hypermedia database • Organizes data as network of nodes • Links nodes in pattern specified by user • Supports text, graphic, sound, video and executable programs
  48. 48. Database Trends A Hypermedia Database Figure 7-20
  49. 49. Database Trends Databases and the Web Database server  Computer in a client/server environment runs a DBMS to process SQL statements and perform database management tasks Application server  Software handling all application operations
  50. 50. Database Trends Linking Internal Databases to the Web Figure 7-21
  51. 51. Thank You