AnnouncementsData ManagementTraditional File ApproachTraditional File StructuresTraditional File Approach – cont’dMoving to Database Management System (DBMS)Database ModelsSlide 8Slide 9Comparison of Data ModelsMajor Database ProductsComponents of Database Management SystemsAdvantages of using SQLDatabase ArchitectureHow to best support organizational needs with a DBMS?Data WarehousingSlide 17Data MiningSlide 19Discussion QuestionsDiscussion questionsAnnouncementsData ManagementChapter 12Traditional File ApproachStructureField  Record  FileFixedAll records have common fields, and a field is the same size across all recordsVariableVariable number of fields within a recordVariable size for a field across recordsTraditional File StructuresSequential AccessBatch ProcessMaster File UpdatesIndexed FilesUse an index to locate a specific recordIndexed-SequentialWay to store data sequentially and use indices to accessTraditional File Approach – cont’dAdvantagesSimplicityEfficiencyCustomizationDisadvantagesProgram/Data DependencyData Redundancy Data IntegrityMoving to Database Management System (DBMS)AdvantagesReduced data redundancyApplication/data independenceBetter controlSecurity: Giving users different views addresses security issueFlexibilityQueries: Request data from specified fieldsDatabase ModelsThe Hierarchical ModelRecords are related hierarchically -- each category is a subcategory of the next level upDisadvantages of hierarchical databasesTo retrieve a record, a user must start at the root and navigate the hierarchy.If a link is broken, the entire branch is lost.Requires considerable data redundancyDatabase ModelsThe Network ModelAllows a record to be linked to more than one parentSupports many-to-many (N:M) relationshipsAdvantage of the network modelReduced data redundancyDisadvantages of the network modelComplicated to build and difficult to maintainDifficult to navigateDatabase ModelsThe Relational ModelConsists of tables; links among entities are maintained with foreign keysAdvantages of relational databasesSame advantages of a network database without the complicationsEasier to conceptualize and maintainVirtually all DBMSs offered for microcomputers accommodate the relational modelComparison of Data ModelsHierarchical Network RelationalConceptualization Moderately EasyDifficult EasyEase of Design Very DifficultModerately DifficultDifficultEase of Maintenance Difficult Very Difficult EasyData Redundancy High Low LowEase of Use Moderate Low HighMajor Database ProductsHierarchicalFocus, IMS, BtrieveNetworkAdabas, ImageRelationalAccess, DB2, dBase V, FoxPro, ParadoxOracle, Sybase, Rbase, Sql ServerComponents of Database Management SystemsThe SchemaDescribes the structure of the database The Data Dictionary (Metadata)Maintains all information supplied by the developer when constructing the schemaData Definition Language (DDL)Used to construct the schemaData Manipulation Language (DML)Used to query the databaseAdvantages of using SQLStructured Query Language (SQL)International standard DDL and DML for relational DBMSUsers do not need to learn different DDLs and DMLs.SQL can be embedded in widely used 3rd generation languages, increasing efficiency and effectiveness.Programmer not forced to rewrite statements since SQL statements are portable.Database ArchitectureDistributed DatabasesReplicationFull copy of the entire database is stored at all sitesFragmentation (distributed)Parts of database are stored where they are most often accessedHow to best support organizational needs with a DBMS?Single, large, centralized repositoryPromotes maintenance and securityAs size of database grew, performance sufferedBroadband still emerging, very expensiveMultiple smaller distributed databasesSome combinationDoes everyone need access to real-time data?dbdbdbDistributeddbdbData WarehousingData warehouseCollection of data that supports management decision makingPhases in Building a Data WarehouseExtraction PhaseCleansing PhaseLoading PhaseData MiningSelecting, exploring, and modeling data to discover unknown relationshipsUse data modeling and “AI” techniquesDiscussion QuestionsDistinguish the traditional file approach from the database approach. What are the primary differences in terms of how they store data? What are the advantages and disadvantages of the following types of database models: hierarchical, network, relational, and Object Oriented? What alternative file-access methods are available to implement a database at the physical level? What factors should you consider when choosing among these alternative methods? What is a DBMS and what are some of the key components of a DBMS?Discussion questionsDiscussion questions, pg 446-47: 17, 22, 25, and