Data and Applications Security Developments and DirectionsObjective of the UnitOutline of the UnitConcepts in Database SystemsDatabase SystemAn Example Database SystemMetadataThree-level Schema Architecture: DetailsFunctional ArchitectureDBMS Design IssuesOther IssuesTypes of Database SystemsRelational Database: Informal OverviewRelational Database: ExampleConcepts in Object Database SystemsExample Class HierarchyExample Composite ObjectDeductive Database SystemsA Definition of a Distributed Database SystemArchitectureDistributed ProcessorData DistributionDistributed Database FunctionsQuery Processing Example (Concluded)Transaction Processing ExampleInteroperability of Heterogeneous Database SystemsTechnical Issues on the Interoperability of Heterogeneous Database SystemsDifferent Data ModelsSchema Integration and Transformation: An approachSemantic HeterogeneityFederated Database ManagementAutonomySchema Integration and Transformation in a Federated EnvironmentFederated Data and Policy ManagementCurrent Status and DirectionsData and Applications Security Developments and DirectionsDr. Bhavani ThuraisinghamThe University of Texas at DallasLecture #2Supporting Technologies: Data ManagementJanuary 13, 2005Objective of the UnitThis unit will provide an overview of the concepts and developments in data management Reference: Data Management Systems: Evolution and Interoperation, Thuraisingham, CRC Press, 1997Outline of the UnitConcepts in database systemsTypes of database systemsDistributed Data ManagementHeterogeneous database integrationFederated data managementConcepts in Database SystemsDefinition of a Database systemEarly systemsMetadataArchitectural Issues-Schema, FunctionalDBMS Design IssuesOther Issues-Database design, AdministrationDatabase SystemConsists of database, hardware, Database Management System (DBMS), and usersDatabase is the repository for persistent dataHardware consists of secondary storage volumes, processors, and main memoryDBMS handles all users’ access to the databaseUsers include application programmers, end users, and the Database Administrator (DBA)Need: Reduced redundancy, avoids inconsistency, ability to share data, enforce standards, apply security restrictions, maintain integrity, balance conflicting requirementsWe have used the definition of a database management system given in C. J. Date’s Book (Addison Wesley, 1990)An Example Database SystemDatabaseDatabase Management SystemApplicationProgramsUsersAdapted from C. J. Date, Addison Wesley, 1990MetadataMetadata describes the data in the database-Example: Database D consists of a relation EMP with attributes SS#, Name, and SalaryMetadatabase stores the metadata -Could be physically stored with the databaseMetadatabase may also store constraints and administrative informationMetadata is also referred to as the schema or data dictionaryThree-level Schema Architecture: DetailsExternalSchema AExternalSchema BConceptualSchemaInternalSchemaUser A1User A2 User A3 User B1User B2ExternalModel AExternalModel BConceptualModelStoredDatabaseInternal ModelExternal/ConceptualMapping BExternal/ConceptualMapping AConceptual/Internal MappingFunctional ArchitectureUser Interface ManagerQueryManagerTransaction ManagerSchema(Data Dictionary)Manager (metadata)Security/IntegrityManagerFileManagerDiskManagerData ManagementStorage ManagementDBMS Design IssuesQuery Processing-Optimization techniquesTransaction Management-Techniques for concurrency control and recoveryMetadata Management-Techniques for querying and updating the metadatabaseSecurity/Integrity Maintenance-Techniques for processing integrity constraints and enforcing access control rulesStorage management-Access methods and index strategies for efficient access to the databaseOther IssuesDatabase design-Generally a two-step processSemantic data model to capture the entities of the application and the relationships between the entitiesGenerate the conceptual schema; theory of normal forms for relational databases-Research on object-oriented approaches for database designDatabase Administration-Creating and deleting databases; backup and recovery, enforcing policies, auditing, etc.Types of Database SystemsRelational Database SystemsObject Database SystemsDeductive Database SystemsOther-Real-time, Secure, Parallel, Scientific, Temporal, Wireless, Functional, Entity-Relationship, Sensor/Stream Database Systems, etc.Relational Database: Informal OverviewCollection of tables also called relationsTable has one or more columns also called attributesEach table has zero or more rows also called tuplesElements of a row take values from a pool of legal valuesThe values of one or more columns in a row uniquely identify the row. These columns form an identifier (also called key)One identifier is designated as the unique identifier (also called primary key)Querying relational databases using language called SQL (Structured Query Language)Relational Database: ExampleRelation S:S# SNAME STATUS CITYS1 Smith 20 LondonS2 Jones 10 ParisS3 Blake 30 ParisS4 Clark 20 LondonS5 Adams 30 AthensRelation P:P# PNAME COLOR WEIGHT CITYP1 Nut Red 12 LondonP2 Bolt Green 17 ParisP3 Screw Blue 17 RomeP4 Screw Red 14 LondonP5 Cam Blue 12 ParisP6 Cog Red 19 LondonRelation SP:S# P# QTYS1 P1 300S1 P2 200S1 P3 400S1 P4 200S1 P5 100S1 P6 100S2 P1 300S2 P2 400S3 P2 200S4 P2 200S4 P4 300S4 P5 400Concepts in Object Database SystemsObjects- every entity is an object-Example: Book, Film, Employee, CarClass -Objects with common attributes are grouped into a class Attributes or Instance Variables-Properties of an object class inherited by the object instancesClass Hierarchy-Parent-Child class hierarchyComposite objects-Book object with paragraphs, sections etc. Methods-Functions associated with a classExample Class HierarchyDocumentClassD1D2Book SubclassB1# of ChaptersVolume #Print-doc-att(ID)Method1:JournalSubclassJ1Print-doc(ID)Method2: ID Name Author PublisherExample Composite ObjectCompositeDocumentObjectSection
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