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Database Management Systems

Prof. Weining ZhangDept. of Computer Science

University of Texas at San Antonio

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OverviewWe study the internal of DBMSs

Principles of relational DBMSs• Emphasize on query & transaction processing

techniquesAdvanced database systems & applications

• OODBMS, XML database, data warehousing, OLAP, data mining

Course work includes Homework, 2 midterm exams, no final examProgramming assignments in Java

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Teaching Staff

Instructor: Prof. Weining ZhangOffice: SB 4.01.19Phone: 458-5557Email: wzhang@cs.utsa.eduOffice hour: MW 5:00 – 6:00 pm

T 4:00-5:00 pmand by appointment

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CommunicationWeb page: http://www.cs.utsa.edu/~wzhang/cs5443/home

Contains everything about the course: syllabus, announcement, assignments, project, lecture notes, etc.

You should check course web pages regularly.Mailing list: 5443@cs.utsa.edu

Include your CS email address; you may need to forward emails to your regular email address

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Textbooks

Required textbook:Database Management systems, 3rd ed., by Ramakrishnan & Gehrke

Recommended textbook:Principles of Distributed Database Systems, by M. Ozsu & P. ValduriezDatabase System: the Complete Book, by Garcia-Molina, Ullman & WidomDatabase system concepts, 5th ed., by Silberschatz, Korth & Sudarshan

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Other Textbooks

Fundamentals of Database Systems, 5th ed., by Elmasri & NavatheOther database books in the Main Library

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PrerequisiteCS3743 or equivalent, or extensive experience with database & DB applicationStrong Java programming skills Data structures, algorithms, OO programming, etc.Mathematics including logic, sets, algebra, …

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Grading

Programming assignments 20%Homework 20%Midterm I 25%Midterm II 25%Intangibles 10%

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Programming Assignments

Implement several components of a simple DBMS called Minibase (Java version), such as,

Buffer ManagerHeap FileHash-based IndexRelational operatorsQuery processing

Work in groups of 2Programming in Java, on Linux or Windows, recommend using Eclipse IDE

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Introduction to Database SystemsA database system consists of

Database management system: the softwareDatabases: the data

A DBMS needs to providepersistent data storagedeclarative query language for efficient data retrieval shared access to data by different applicationsdata securitydata integrity …

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An RDBMS Architecture

Web forms Application front end SQL interface

SQL Commands

Sys. catalogIndex filesData files

Parser Optimizer

Plan Executor Operator Evaluator

QueryEvaluationEngine

File & Access Methods

Buffer Manager & Disk Manager

RecoveryManager

Xction Man

Lock Man

ConcurrencyControl

DBMS

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Storage ManagementData is stored on disks, and processed in the main memorySince disk I/Os are costly, search structures, such as, indexes, must be used to achieve efficient data accessDBMS components that manage different types of storage include

Disk Manager: manages pages on disk driveBuffer Manager: manages pages in main memory buffer

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File OrganizationData records are logically organized in files and physically stored on disk pagesFile organization must consider the format and size of data recordsIn addition to simple files of raw data, DBMS also maintains search structures, such as,

OrderingHashingIndexing

to reduce access costs

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Query ProcessingDBMS evaluates declarative queries by executing an optimal query plan that is expressed using relational algebraic operations. A DBMS must evaluate algebraic operations efficiently.The algorithms and the costs of relational algebraic operations, such as, selection and join, depend critically on

types of query conditionspecifics of file organizations

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Query Optimization

For easy of use, query languages are declarative. The system must figure out an efficient evaluation planThe goal is to answer a query with as few disk I/O as possibleThe system uses statistics of the data & heuristics to decide how to process the query

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Transaction ProcessingA transaction models the execution of a database application, which typically updates the data in databases. Transaction management must deal with concurrent transactions and possible system failures.

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RecoveryThe recovery manager protects data integrity in case of system crash. The system guarantees that either all operations of a transaction or none of them are performed, and updates made by completed transactions are persistent.

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Concurrency Control Concurrent execution of application programs is essential for good DBMS performance.

Need to keep CPU busy while performing I/O operations (frequent & relatively slow).

Interleaving actions of different user programs can lead to inconsistency: e.g., check is cleared while account balance is being computed.Concurrency control subsystem ensures such problems don’t arise: users can pretend they are using a single-user system.

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Advanced Hashing & IndexingRelational DBMS support hashing & B+ tree indexingNew DBMSs & DB applications need more sophisticated search structures

Hashing with variable size hash table or multiple keysIndexes for spatial, multidimensional data (common in multimedia DBSs, Data warehousing, OLAP, …)

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Distributed DBMSModern corporations have data, control, & application distributed globallyMultiple databases at geographically dispersed locations need to cooperate to answer queries with distributed dataConcurrent transaction processing and recovery are still major issues

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Parallel DBMSBoth centralized and distributed databases may use multiple processors to evaluate queriesParallel system architecture requires new algorithms for query evaluation and optimizationPerformance concerns include

Ability to scale upAbility to speed up

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XML & Semistructured DBMSData in RDB, OODB, & ORDB are structured (with rigid schemas)Data on the Web (and other applications) are semistructured

HTML, XML, Text, …

Need new concepts and techniquesData model, query languageQuery processing & optimizationStorage managementUpdate, transaction processing, CC, …

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Data Warehousing & OLAPCorporations need to put all available data into use when making vital business decisionsNeed to have technology to integrate data from all sources, and keep them up to dateNeed advanced tools to analyze, summarize, and view data in various ways Issues:

Data cube modelOLAP operationsQuery processing, indexing, views, …

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Data MiningData contains important patterns useful for making sound business decisionsDatabases need tools to discover knowledge embedded in data

AssociationsClustersClassifications

Useful for business trend analysis, fraud detection, diagnosis, market prediction, …

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TopicsRelational algebra and calculusStorage & File Management

Disk manager, buffer manager, Indexing, hashing

Query Evaluation & OptimizationAccess methods, selection, joins, etc.Query optimization methods

Transaction ProcessingCrash RecoveryConcurrency Control

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Topics (cont.)Distributed Database Systems

Database designQuery processing & optimizationConcurrency control & recovery

Parallel Database systemsXML databasesData Warehousing and OLAP Data Mining, …