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The document provides an overview of database systems, their evolution from file systems, and different database models. It discusses the limitations of file systems, including data redundancy and inconsistencies. A database management system (DBMS) addresses these issues by allowing for a centralized, integrated view of shared data. The chapter then describes several database models - hierarchical, network, relational, entity-relationship, and object-oriented - covering their structure and advantages/disadvantages. The relational model is now dominant due to its simplicity, flexibility and ability to handle complex queries.

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Chapter 1File Systems and DatabasesDatabase Systems: Design, Implementation, and Management, Fifth Edition, Rob and Coronel
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel2In this chapter, you will learn:What a database is, what it does, and why database design is importantHow modern databases evolved from files and file systemsAbout flaws in file system data managementWhat a DBMS is, what it does, and how it fits into the database systemAbout types of database systems and database models
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel3Introducing the DatabaseData versus InformationData constitute building blocks of informationInformation produced by processing dataInformation reveals meaning of dataGood, timely, relevant information key to decision makingGood decision making key to organizational survival
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel4Database ManagementDatabase is shared, integrated computer structure housing:End user dataMetadataDatabase Management System (DBMS)Manages Database structureControls access to dataContains query language
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel5Importance of DBMSMakes data management more efficient and effective
Query language allows quick answers to ad hoc queries
Provides better access to more and better-managed data
Promotes integrated view of organization¡¯s operations
Reduces the probability of inconsistent dataDatabase Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel6DBMS Manages InteractionFigure 1.2
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel7Database DesignImportance of Good DesignPoor design results in unwanted data redundancyPoor design generates errors leading to bad decisionsPractical ApproachFocus on principles and concepts of database designImportance of logical design
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel8Historical Roots of DatabaseFirst applications focused on clerical tasksRequests for information quickly followedFile systems developed to address needsData organized according to expected useData Processing (DP) specialists computerized manual file systems
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel9File TerminologyData Raw FactsFieldGroup of characters with specific meaningRecordLogically connected fields that describe a person, place, or thingFileCollection of related records
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel10Simple File SystemFigure 1.5
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel11File System CritiqueFile System Data ManagementRequires extensive programming in third-generation language (3GL)Time consumingMakes ad hoc queries impossibleLeads to islands of information
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel12File System Critique (con¡¯t.)Data DependenceChange in file¡¯s data characteristics requires modification of data access programsMust tell program what to do and howMakes file systems cumbersome from programming and data management viewsStructural DependenceChange in file structure requires modification of related programs
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel13File System Critique (con¡¯t.)Field Definitions and Naming ConventionsFlexible record definition anticipates reporting requirementsSelection of proper field names importantAttention to length of field namesUse of unique record identifiers
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel14File System Critique (con¡¯t.)Data RedundancyDifferent and conflicting versions of same data Results of uncontrolled data redundancyData anomaliesModificationInsertionDeletionData inconsistencyLack of data integrity
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel15Database SystemsDatabase consists of logically related data stored in a single repositoryProvides advantages over file system management approachEliminates inconsistency, data anomalies, data dependency, and structural dependency problemsStores data structures, relationships, and access paths
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel16Database vs. File SystemsFigure 1.6
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel17Database SystemEnvironmentFigure 1.7
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel18Database System TypesSingle-user vs. Multiuser DatabaseDesktopWorkgroupEnterpriseCentralized vs. DistributedUseProduction or transactionalDecision support or data warehouse
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel19DBMS FunctionsData dictionary managementData storage managementData transformation and presentationSecurity managementMultiuser access controlBackup and recovery managementData integrity managementDatabase language and application programming interfaces Database communication interfaces
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel20Database ModelsCollection of logical constructs used to represent data structure and relationships within the databaseConceptual models: logical nature of data representationImplementation models: emphasis on how the data are represented in the database
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel21Database Models (con¡¯t.)Relationships in Conceptual ModelsOne-to-one (1:1)One-to-many (1:M)Many-to-many (M:N)Implementation Database ModelsHierarchical Network Relational
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel22Hierarchical Database ModelLogically represented by an upside down treeEach parent can have many childrenEach child has only one parentFigure 1.8
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel23Hierarchical Database ModelAdvantagesConceptual simplicityDatabase security and integrityData independenceEfficiencyDisadvantagesComplex implementationDifficult to manage and lack of standardsLacks structural independenceApplications programming and use complexityImplementation limitations
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel24Network Database ModelEach record can have multiple parentsComposed of setsEach set has owner record and member recordMember may have several ownersFigure 1.10
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel25Network Database ModelAdvantagesConceptual simplicityHandles more relationship typesData access flexibilityPromotes database integrityData independenceConformance to standardsDisadvantagesSystem complexityLack of structural independence
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel26Relational Database ModelPerceived by user as a collection of tables for data storageTables are a series of row/column intersectionsTables related by sharing common entity characteristic(s)
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel27Relational Database Model (con¡¯t.)Figure 1.11
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel28Relational Database ModelAdvantagesStructural independenceImproved conceptual simplicityEasier database design, implementation, management, and use Ad hoc query capability with SQLPowerful database management system
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel29Relational Database ModelDisadvantagesSubstantial hardware and system software overheadPoor design and implementation is made easyMay promote ¡°islands of information¡± problems
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel30Entity Relationship Database ModelComplements the relational data model conceptsRepresented in an entity relationship diagram (ERD)Based on entities, attributes, and relationshipsFigure 1.13
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel31Entity Relationship Database ModelAdvantagesExceptional conceptual simplicityVisual representationEffective communication toolIntegrated with the relational database modelDisadvantagesLimited constraint representationLimited relationship representationNo data manipulation languageLoss of information content
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel32Object-Oriented Database ModelObjects or abstractions of real-world entities are stored Attributes describe propertiesCollection of similar objects is a classMethods represent real world actions of classesClasses are organized in a class hierarchy Inheritance is ability of object to inherit attributes and methods of classes above it
Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel33Comparison of OO and E-R Data ModelsFigure 1.15

More Related Content

01 chapter

  • 1. Chapter 1File Systems and DatabasesDatabase Systems: Design, Implementation, and Management, Fifth Edition, Rob and Coronel
  • 2. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel2In this chapter, you will learn:What a database is, what it does, and why database design is importantHow modern databases evolved from files and file systemsAbout flaws in file system data managementWhat a DBMS is, what it does, and how it fits into the database systemAbout types of database systems and database models
  • 3. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel3Introducing the DatabaseData versus InformationData constitute building blocks of informationInformation produced by processing dataInformation reveals meaning of dataGood, timely, relevant information key to decision makingGood decision making key to organizational survival
  • 4. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel4Database ManagementDatabase is shared, integrated computer structure housing:End user dataMetadataDatabase Management System (DBMS)Manages Database structureControls access to dataContains query language
  • 5. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel5Importance of DBMSMakes data management more efficient and effective
  • 6. Query language allows quick answers to ad hoc queries
  • 7. Provides better access to more and better-managed data
  • 8. Promotes integrated view of organization¡¯s operations
  • 9. Reduces the probability of inconsistent dataDatabase Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel6DBMS Manages InteractionFigure 1.2
  • 10. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel7Database DesignImportance of Good DesignPoor design results in unwanted data redundancyPoor design generates errors leading to bad decisionsPractical ApproachFocus on principles and concepts of database designImportance of logical design
  • 11. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel8Historical Roots of DatabaseFirst applications focused on clerical tasksRequests for information quickly followedFile systems developed to address needsData organized according to expected useData Processing (DP) specialists computerized manual file systems
  • 12. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel9File TerminologyData Raw FactsFieldGroup of characters with specific meaningRecordLogically connected fields that describe a person, place, or thingFileCollection of related records
  • 13. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel10Simple File SystemFigure 1.5
  • 14. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel11File System CritiqueFile System Data ManagementRequires extensive programming in third-generation language (3GL)Time consumingMakes ad hoc queries impossibleLeads to islands of information
  • 15. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel12File System Critique (con¡¯t.)Data DependenceChange in file¡¯s data characteristics requires modification of data access programsMust tell program what to do and howMakes file systems cumbersome from programming and data management viewsStructural DependenceChange in file structure requires modification of related programs
  • 16. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel13File System Critique (con¡¯t.)Field Definitions and Naming ConventionsFlexible record definition anticipates reporting requirementsSelection of proper field names importantAttention to length of field namesUse of unique record identifiers
  • 17. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel14File System Critique (con¡¯t.)Data RedundancyDifferent and conflicting versions of same data Results of uncontrolled data redundancyData anomaliesModificationInsertionDeletionData inconsistencyLack of data integrity
  • 18. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel15Database SystemsDatabase consists of logically related data stored in a single repositoryProvides advantages over file system management approachEliminates inconsistency, data anomalies, data dependency, and structural dependency problemsStores data structures, relationships, and access paths
  • 19. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel16Database vs. File SystemsFigure 1.6
  • 20. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel17Database SystemEnvironmentFigure 1.7
  • 21. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel18Database System TypesSingle-user vs. Multiuser DatabaseDesktopWorkgroupEnterpriseCentralized vs. DistributedUseProduction or transactionalDecision support or data warehouse
  • 22. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel19DBMS FunctionsData dictionary managementData storage managementData transformation and presentationSecurity managementMultiuser access controlBackup and recovery managementData integrity managementDatabase language and application programming interfaces Database communication interfaces
  • 23. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel20Database ModelsCollection of logical constructs used to represent data structure and relationships within the databaseConceptual models: logical nature of data representationImplementation models: emphasis on how the data are represented in the database
  • 24. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel21Database Models (con¡¯t.)Relationships in Conceptual ModelsOne-to-one (1:1)One-to-many (1:M)Many-to-many (M:N)Implementation Database ModelsHierarchical Network Relational
  • 25. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel22Hierarchical Database ModelLogically represented by an upside down treeEach parent can have many childrenEach child has only one parentFigure 1.8
  • 26. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel23Hierarchical Database ModelAdvantagesConceptual simplicityDatabase security and integrityData independenceEfficiencyDisadvantagesComplex implementationDifficult to manage and lack of standardsLacks structural independenceApplications programming and use complexityImplementation limitations
  • 27. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel24Network Database ModelEach record can have multiple parentsComposed of setsEach set has owner record and member recordMember may have several ownersFigure 1.10
  • 28. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel25Network Database ModelAdvantagesConceptual simplicityHandles more relationship typesData access flexibilityPromotes database integrityData independenceConformance to standardsDisadvantagesSystem complexityLack of structural independence
  • 29. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel26Relational Database ModelPerceived by user as a collection of tables for data storageTables are a series of row/column intersectionsTables related by sharing common entity characteristic(s)
  • 30. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel27Relational Database Model (con¡¯t.)Figure 1.11
  • 31. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel28Relational Database ModelAdvantagesStructural independenceImproved conceptual simplicityEasier database design, implementation, management, and use Ad hoc query capability with SQLPowerful database management system
  • 32. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel29Relational Database ModelDisadvantagesSubstantial hardware and system software overheadPoor design and implementation is made easyMay promote ¡°islands of information¡± problems
  • 33. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel30Entity Relationship Database ModelComplements the relational data model conceptsRepresented in an entity relationship diagram (ERD)Based on entities, attributes, and relationshipsFigure 1.13
  • 34. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel31Entity Relationship Database ModelAdvantagesExceptional conceptual simplicityVisual representationEffective communication toolIntegrated with the relational database modelDisadvantagesLimited constraint representationLimited relationship representationNo data manipulation languageLoss of information content
  • 35. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel32Object-Oriented Database ModelObjects or abstractions of real-world entities are stored Attributes describe propertiesCollection of similar objects is a classMethods represent real world actions of classesClasses are organized in a class hierarchy Inheritance is ability of object to inherit attributes and methods of classes above it
  • 36. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel33Comparison of OO and E-R Data ModelsFigure 1.15
  • 37. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel34OO Data ModelAdvantagesAdds semantic contentVisual presentation includes semantic contentDatabase integrityBoth structural and data independenceDisadvantagesLack of OODMComplex navigational data accessSteep learning curveHigh system overhead slows transactions
  • 38. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel35Development of Data ModelsFigure 1.16
  • 39. Database Systems: Design, Implementation, & Management, 5th Edition, Rob & Coronel36Database Models and the InternetCharacteristics of ¡°Internet age¡± databasesFlexible, efficient, and secure Internet accessEasily used, developed, and supportedSupports complex data types and relationshipsSeamless interfaces with multiple data sources and structuresSimplicity of conceptual database model Many database design, implementation, and application development toolsPowerful DBMS GUI make DBA job easier