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SIM - Mc leod ch06
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SIM - Mc leod ch06

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  • 1. © 2007 by Prentice Hall© 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod and George SchellManagement Information Systems, 10/e Raymond McLeod and George Schell 11 ManagementManagement Information Systems,Information Systems, 10/e10/e Raymond McLeod and George SchellRaymond McLeod and George Schell
  • 2. © 2007 by Prentice Hall© 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod and George SchellManagement Information Systems, 10/e Raymond McLeod and George Schell 22 Chapter 6Chapter 6 Database Management SystemsDatabase Management Systems
  • 3. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod3 Learning ObjectivesLearning Objectives ► Understand the hierarchy of data.Understand the hierarchy of data. ► Understand database structures and how theyUnderstand database structures and how they work.work. ► Know how to relate tables together in a database.Know how to relate tables together in a database. ► Recognize the difference between a database andRecognize the difference between a database and a database management system.a database management system. ► Understand the database concept.Understand the database concept. ► Know two basic methods for determining dataKnow two basic methods for determining data needs.needs.
  • 4. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod4 Learning Objectives (Cont’d)Learning Objectives (Cont’d) ► Understand entity-relationship diagrams and classUnderstand entity-relationship diagrams and class diagrams.diagrams. ► Know the basics of reports and forms.Know the basics of reports and forms. ► Understand the basic difference betweenUnderstand the basic difference between structured query language and query-by-example.structured query language and query-by-example. ► Know about the important personnel who areKnow about the important personnel who are associated with databases.associated with databases. ► Know the advantages and costs of databaseKnow the advantages and costs of database management systems.management systems.
  • 5. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod5 Data HierarchyData Hierarchy ►Data fieldData field is the smallest unit of data.is the smallest unit of data. ►RecordRecord is a collection of related data fields.is a collection of related data fields. ►FileFile is a collection of related records.is a collection of related records. ►DatabaseDatabase is a collection of related files.is a collection of related files.  General definitionGeneral definition  Restrictive definitionRestrictive definition
  • 6. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod6 DatabaseDatabase ► Table of rows & columns can be represented in aTable of rows & columns can be represented in a spreadsheet.spreadsheet. ► Relational database structureRelational database structure is conceptuallyis conceptually similar to a collection of related tables.similar to a collection of related tables. ► Flat fileFlat file is a table that does not have repeatingis a table that does not have repeating columns; 1columns; 1stst normal form.normal form. ► NormalizationNormalization is a formal process for eliminatingis a formal process for eliminating redundant data fields which preserving the abilityredundant data fields which preserving the ability of the database to add, delete, and modify recordsof the database to add, delete, and modify records without causing errors.without causing errors.
  • 7. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod7 Figure 6.1 Spreadsheet as a SimpleFigure 6.1 Spreadsheet as a Simple DatabaseDatabase
  • 8. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod8 Database (Cont’d)Database (Cont’d) ► KeyKey in a table is a field (or combination of fields)in a table is a field (or combination of fields) that contain a value that uniquely identifies eachthat contain a value that uniquely identifies each record in the table.record in the table. ► Candidate keyCandidate key is a field that uniquely identifiesis a field that uniquely identifies each table row but is not the chosen key.each table row but is not the chosen key. ► Relating tables is done through sharing a commonRelating tables is done through sharing a common field & the value of the field determines which rowsfield & the value of the field determines which rows in the tables are logically joined.in the tables are logically joined.
  • 9. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod9 Database Management SystemDatabase Management System ►Database management systemDatabase management system (DBMS)(DBMS) is a software application thatis a software application that stores the structure of the database, thestores the structure of the database, the data itself, relationships among data in thedata itself, relationships among data in the database, and forms & reports pertaining todatabase, and forms & reports pertaining to the database.the database.  Self-describing set of related data.Self-describing set of related data.
  • 10. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod10 Database StructuresDatabase Structures ►HierarchicalHierarchical is formed by data groups,is formed by data groups, subgroups, and further subgroups; likesubgroups, and further subgroups; like branches on a tree.branches on a tree.  Worked well with TPSs.Worked well with TPSs.  Utilized computer resources efficiently.Utilized computer resources efficiently. ►NetworkNetwork allows retrieval of specificallows retrieval of specific records; allows a given record to point torecords; allows a given record to point to any other record in the database.any other record in the database.
  • 11. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod11 Figure 6.2 Hierarchical StructureFigure 6.2 Hierarchical Structure
  • 12. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod12 Database Structures (Cont’d)Database Structures (Cont’d) ►RelationalRelational is when the relationshipis when the relationship between tables are implicit.between tables are implicit. ►Physical relationshipPhysical relationship is when theis when the database structure (hierarchical, network)database structure (hierarchical, network) rely on storage addresses.rely on storage addresses. ►Implicit relationshipImplicit relationship is when theis when the database structure (relational) can bedatabase structure (relational) can be implied from the data.implied from the data.
  • 13. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod13 A Relational Database ExampleA Relational Database Example ►A database namedA database named ScheduleSchedule has been createdhas been created from tables used earlier in the chapter and somefrom tables used earlier in the chapter and some othersothers ►The database is implemented in MicrosoftThe database is implemented in Microsoft Access 2002 (also known as Access XP).Access 2002 (also known as Access XP). ►Databases break information into multiple tablesDatabases break information into multiple tables because if information were stored in a singlebecause if information were stored in a single table, many data field values would betable, many data field values would be duplicated.duplicated.
  • 14. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod14 ScheduleSchedule DatabaseDatabase ► The example is implemented on Microsoft Access DBMS butThe example is implemented on Microsoft Access DBMS but would be similar on any relational DBMS product.would be similar on any relational DBMS product. ► The COURSE table in Access (Figure 6.4) is a list of data fieldThe COURSE table in Access (Figure 6.4) is a list of data field values. The table itself had to be defined in Access before valuesvalues. The table itself had to be defined in Access before values were entered into the data fields.were entered into the data fields. ► Figure 6.5 shows the definition of theFigure 6.5 shows the definition of the CodeCode field.field. ► Figure 6.6 illustrates thatFigure 6.6 illustrates that AbbreviationAbbreviation field values will befield values will be looked up from a list of values in the DEPARTMENT table.looked up from a list of values in the DEPARTMENT table. ► Table 6.7 shows a single table of course and department fieldsTable 6.7 shows a single table of course and department fields before they were separated into different tables.before they were separated into different tables.
  • 15. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod15 Figure 6.4 The COURSE TableFigure 6.4 The COURSE Table
  • 16. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod16 Figure 6.5 Defining the CODE FieldFigure 6.5 Defining the CODE Field
  • 17. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod17 Figure 6.6 Look-up ValuesFigure 6.6 Look-up Values
  • 18. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod18 Table 6.7Table 6.7
  • 19. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod19 Figure 6.7 Access ViewFigure 6.7 Access View
  • 20. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod20 Database ConceptDatabase Concept ► Database conceptDatabase concept is the logical integration ofis the logical integration of records across multiple physical locations.records across multiple physical locations. ► Data independenceData independence is the ability to makeis the ability to make changes in the data structure without makingchanges in the data structure without making changes to the application programs that accesschanges to the application programs that access the data.the data. ► Data dictionaryData dictionary includes the definition of theincludes the definition of the data stored within the database & controlled by thedata stored within the database & controlled by the database management system.database management system.
  • 21. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod21 Creating a DatabaseCreating a Database ►Determine data that needs to be collected &Determine data that needs to be collected & stored is a key step.stored is a key step. ►Process-oriented approachProcess-oriented approach  Define the problem.Define the problem.  Identify necessary decisions.Identify necessary decisions.  Describe information needs.Describe information needs.  Determine the necessary processing.Determine the necessary processing.  Specify data needs.Specify data needs.
  • 22. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod22 Determine Data Needs (Cont’d)Determine Data Needs (Cont’d) ►Enterprise modeling approachEnterprise modeling approach takes atakes a broad view of the firm’s data resources; allbroad view of the firm’s data resources; all areas are considered, & synergy of dataareas are considered, & synergy of data resources between business areas can beresources between business areas can be leveraged.leveraged.  Result:Result: Enterprise data modelEnterprise data model
  • 23. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod23 Figure 6.8 Enterprise Data ModelFigure 6.8 Enterprise Data Model
  • 24. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod24 Data Modeling TechniquesData Modeling Techniques ►Entity-relationship diagrams (ERDs)Entity-relationship diagrams (ERDs) is a graphical representation of data inis a graphical representation of data in entities and the relationships betweenentities and the relationships between entities.entities. ►EntityEntity is a conceptual collection of relatedis a conceptual collection of related data fields.data fields. ►RelationshipRelationship is defined between entities.is defined between entities.  One-to-one – 1:1One-to-one – 1:1  One-to-many – 1:MOne-to-many – 1:M  Many-to-many – M:NMany-to-many – M:N
  • 25. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod25 Figure 6.11 Entity-relationshipFigure 6.11 Entity-relationship DiagramDiagram
  • 26. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod26 Diagramming Techniques (Cont’d)Diagramming Techniques (Cont’d) ►Class DiagramClass Diagram is a graphicalis a graphical representation of both the data used in anrepresentation of both the data used in an application and the actions associated withapplication and the actions associated with the data; object-oriented design modelthe data; object-oriented design model ►ObjectsObjects are the data, actions taken on theare the data, actions taken on the data, & relationship between objects.data, & relationship between objects. ►Class diagrams consist of the named class,Class diagrams consist of the named class, fields in the class, & actions (fields in the class, & actions (methodsmethods) that) that act upon the class.act upon the class.
  • 27. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod27 Figure 6.13 Class DiagramFigure 6.13 Class Diagram
  • 28. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod28 Using the DatabaseUsing the Database ►FormsForms show 1 record at a time & can beshow 1 record at a time & can be used to add, delete, or modify databaseused to add, delete, or modify database records.records.  NavigationNavigation  AccuracyAccuracy  ConsistencyConsistency  FilteringFiltering  subformssubforms
  • 29. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod29 Figure 6.15 Combined Data EntryFigure 6.15 Combined Data Entry FormForm
  • 30. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod30 Using the Database (Cont’d)Using the Database (Cont’d) ►ReportsReports are aggregated data from theare aggregated data from the database that are formatted in a mannerdatabase that are formatted in a manner that aids decision making.that aids decision making. ►QueriesQueries is a request for the database tois a request for the database to display selected records.display selected records. ►Query-by-example (QBE)Query-by-example (QBE) presents apresents a standardized form that the user completesstandardized form that the user completes so the system can generate a true query.so the system can generate a true query.
  • 31. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod31 Figure 6.16 Report of DepartmentsFigure 6.16 Report of Departments
  • 32. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod32 Structured Query LanguageStructured Query Language ►Structured query language (SQL)Structured query language (SQL) isis the code that RDBMSs use to perform theirthe code that RDBMSs use to perform their database tasks.database tasks. ►Method of choice for interacting with web-Method of choice for interacting with web- based databases.based databases. ►Writing SQL statements are not difficult forWriting SQL statements are not difficult for most manager’s data needs.most manager’s data needs.
  • 33. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod33 Figure 6.20 SQL CodeFigure 6.20 SQL Code
  • 34. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod34 Advanced Database ProcessingAdvanced Database Processing ► On-line analytical processing (OLAP)On-line analytical processing (OLAP) allowsallows data analysis similar to statistical cross-tabulation.data analysis similar to statistical cross-tabulation. ► Data miningData mining,, data martsdata marts, &, & data warehousingdata warehousing focus on methodologies that offer users quickfocus on methodologies that offer users quick access to aggregated data specific to theiraccess to aggregated data specific to their decision-making needs.decision-making needs. ► Knowledge discoveryKnowledge discovery analyzes data usage &analyzes data usage & data commonality among different tables.data commonality among different tables.
  • 35. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod35 Database PersonnelDatabase Personnel ►Database Administrator (DBA)Database Administrator (DBA) is anis an expert in developing, providing, andexpert in developing, providing, and securing databases; duties includesecuring databases; duties include  Database planning;Database planning;  Database implementation;Database implementation;  Database operation;Database operation;  Database security.Database security.
  • 36. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod36 Database Personnel (Cont’d)Database Personnel (Cont’d) ►Database programmerDatabase programmer writes code towrites code to strip and/or aggregate data from thestrip and/or aggregate data from the databasedatabase  High level of specialization & selectionHigh level of specialization & selection ►End userEnd user generates reports & forms, postgenerates reports & forms, post queries to the database, & use results fromqueries to the database, & use results from their database inquiries to make decisionstheir database inquiries to make decisions that affect the firm & its environmentalthat affect the firm & its environmental constituents.constituents.
  • 37. © 2007 by Prentice Hall Management Information Systems, 10/e Raymond McLeod37 DBMSs in PerspectiveDBMSs in Perspective ►DBMS AdvantagesDBMS Advantages  Reduce data redundancy.Reduce data redundancy.  Achieve data independence.Achieve data independence.  Retrieve data & information rapidly.Retrieve data & information rapidly.  Improve security.Improve security. ►DBMS DisadvantagesDBMS Disadvantages  Obtain expensive software.Obtain expensive software.  Obtain a large hardware configuration.Obtain a large hardware configuration.  Hire and maintain a DBA staff.Hire and maintain a DBA staff.

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