Databases Systems ICS 184CS 184 Course Web ServerCourse InfoDesiderataDesiderata (cont.)PoliciesMaterial Covered in CS 184Database Management EnvironmentTraditional DBMS GoalsDatabases and File SystemsData AbstractionData AbstractionSchemas and InstancesData ModelTypes of Data ModelsTypes of Data Model (cont.)Entity-Relationship ModelEntity Relationship Model (Cont.)Relational ModelA Sample Relational DatabaseClassification of DBMSs based on Data ModelDBMS LanguagesData Definition Language (DDL)Data Manipulation Language (DML)SQLApplication ArchitecturesDBMS InterfacePeople Involved with DBMSsDBMS ArchitectureKey Database TechnologiesNeed for Query OptimizationStrategies 1Strategy 2Transaction ConceptExample of TransactionMotivation of IsolationImportance of the TransactionsTransactions versus Other Concurrent Programming EnvironmentsDatabases Systems ICS 184Professor MehrotraRoom 424Computer Science DepartmentUniversity of California IrvineTel: 949 824 5975CS 184 Course Web ServerAll course information will be posted on lineURL: http://www.ics.uci.edu/~dbclass/ics184/index.htmlClass Notes available before class on the Web.Course InfoTAs Koushik NiyogiOffice and office Hours:Monday : 1:00-2:00 PMWednesday :12:30-1:30 PMLocation : 124 CST (CS trailer)Rajat Mathur Office and office Hours: TBAInstructorOffice Hours:Tue 11-12 pm (send email)Email: [email protected]to contact me urgently, send email and mark subject line as CS 184 URGENTDesiderataCourse Text: (either of following two books will suffice)A First Course in Database Systems, Ullman and Widom we will cover the entire bookDatabase Systems Concepts, Silberschatz, Korth, and Sudarshanwe will cover chapters 1-9Software:Course will involve significant programming. You will get exposure to database programming in DB2Desiderata (cont.)Course Requirements:Problem sets ~ approx. every week to 10 days.Total not to exceed 8MidtermFinal (comprehensive)Grades:Problem sets 15%Personal Database Assignment (project) 15%Midterm 30%Final 40%PoliciesLate AssignmentsNo grace period after due date…. except under exceptional circumstancesjob interviews, out of town trip, breaks etc do not qualify as exceptional circumstances!Working in Groupsdo your homework problem sets in group size not to exceed 3learn moreget better gradesget used to working in groups (important to employers) Do exams individually!!Material Covered in CS 184Four aspects of studying DBMSsModeling and design of databasesallows exploration of issues before committing to an implementationProgramming: queries and DB operations like update.SQL == “intergalactic dataspeak” DBMS implementationEffect of technology and application advances to database technology.CS 184 == (1) + (2)CS 214 == (3)CS215 == (3) + (4)Applications/queriesQuery processorStorage managerusermetadatadatabaseDatabase: collection of interrelated information about world being modeledDBMS:general purpose software to define, create, modify, retrieve, delete and manipulate a databaseVendors: Informix, Oracle, O2, Sybase, IBM, DECDBMSDatabase Management EnvironmentTraditional DBMS GoalsEfficient management of (faster than files) large amounts of (gigabytes) of persistent (outlasts creator), reliable (outlasts crashes) shared information (multiple users). DBMS Users:small and large corporationsE-commerce companies, banks, airlines, transportation companies, corporate databases, government agencies, defense.Anyone you can think of!Databases and File SystemsDBMSs evolved from file systems.DBMSs provide many features that traditional file systems do not.Support for concurrent access and data sharing. Data consistency in presence of concurrencyReliability in presence of failures and system crashes.Efficient associative access to very large amounts of dataA high level Query language (SQL) to define, create, access, and manipulate data. Support for unanticipated queriessupport for multiple data viewssecurity and authorizationdata abstractionprevention of data redundancy and inconsistenciesData Abstractionprogram data independence: ability to hide details of how data is stored and maintained from application programsprogram-operation independence:ability to hide details of operation implementation from application programs (Object-Orientation)Physical levelLogical LevelView1View 2 View nPhysical description of data, storage organizationConceptual representationCustomized views Data AbstractionHiding system complexity, physical storage details from users and application programsInstance: set of data currently instantiated in databasechanges frequentlySchema: overall design, structure, and constraints over the database referred to as metadatachanges infrequentlyExample:Schema InstanceTablesEmp (ename, dep#)Dept(dep#, dname, mgr)Constraintseach department has a single manager(John, 10), (Cindy, 15), (Martha, 10)(10, Toy, John), (15, Sales, Cindy)EmpSchemas and InstancesdeptData ModelSet of concepts and tools used to describe the database schemaDifferent schemas at different abstraction levels: physical schema: describes physical organization of datalogical schema: describes data at conceptual levelsub schema: defines data at view levelDifferent models used describe schemas at different abstraction levelsTypes of Data ModelsObject based Logical ModelsUsed to describe schema at view and logical levels. Support abstract view of data as objects, relationships, constraintsExample: Entity Relationship Model, Functional data Model, Semantic Model, Object Oriented Model like ODLTypes of Data Model (cont.)Record-Based Logical ModelsUsed to define data at view and logical levels.Provide a high level description of implementationExamples:Relational Model, Hierarchical Model, Network ModelPhysical ModelsUsed to describe data at implementation level.Examples: Frame Memory Model, Unifying ModelEntity-Relationship ModelExample of schema in the entity-relationship modelEntity Relationship Model (Cont.)E-R model of real worldEntities (objects) E.g. customers, accounts, bank branchRelationships between entitiesE.g. Account A-101 is held by customer JohnsonRelationship set depositor