database system - ch01
TRANSCRIPT
The Worlds of Database SystemsThe Worlds of Database Systems
Prof. Yin-Fu HuangProf. Yin-Fu HuangCSIE, NYUST CSIE, NYUST
Chapter 1Chapter 1
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1.11.1 The Evolution of Database SystemsThe Evolution of Database Systems
Database: a collection of data that is managed by a DBMS The DBMS is expected to:
1) Specify the schema using a specialized data-definition language
2) Give users the ability to query and modify the data using data-manipulation language
3) Support the storage of very large amounts of data4) Enable durability5) Control access to data from many users at once
(isolation and atomicity)
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The first commercial DBMS appeared in the late 1960’s. File systems : only item (3) supported Applications of DBMS:
1) Banking systems2) Airline reservation systems3) Corporate record keeping
Hierarchical model and network model
1.1.11.1.1 Early Database Management SystemsEarly Database Management Systems
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Since 1970, data systems change significantly. Relations SQL Object-oriented features
1.1.21.1.2 Relational Database SystemsRelational Database Systems
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Database systems available for even very small machines.
The use of documents often tagged using XML
1.1.31.1.3 Smaller and Smaller SystemsSmaller and Smaller Systems
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Some important examples:1) Google2) Satellites3) Flickr or Amazon4) YouTube5) Peer-to-peer file-sharing systems
1.1.41.1.4 Bigger and Bigger SystemsBigger and Bigger Systems
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To build structures on top of existing databases1) Data ware-houses2) Middleware: an integrated model
1.1.51.1.5 Information IntegrationInformation Integration
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1.21.2 Overview of a Database Management SystemOverview of a Database Management System
(See Fig. 1.1) Two distinct sources of commands:
1) Conventional users and application programs2) A database administrator
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1.21.2 Overview of a Database Management SystemOverview of a Database Management System
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Metadata
1.2.11.2.1 Data-Definition Language CommandsData-Definition Language Commands
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Two separate subsystems:
1) Answering the query a. Buffer manager
b. Storage manager
2) Transaction processing a. A concurrency-control manager, or scheduler, responsible for assuring atomicity and isolation of transactions
b. A logging and recovery manager, responsible for the durability of transactions
1.2.21.2.2 Overview of Query ProcessingOverview of Query Processing
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The kinds of information:1) Data2) Metadata3) Log records4) Statistics5) Indexes
1.2.31.2.3 Storage and Buffer ManagementmsStorage and Buffer Managementms
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It is normal to group one or more database operations into a transaction, which is a unit of work.
The tasks performed by the transaction processor:1) Logging
2) Concurrency control3) Deadlock resolution
1.2.41.2.4 Transaction ProcessingTransaction Processing
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Two components:1) Query compiler query plan⇒a. Query parserb. Query preprocessor
c. Query optimizer
2) Execution engine
1.2.51.2.5 The Query processorThe Query processor
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1.31.3 Outline of Database-System StudiesOutline of Database-System Studies
Five parts:1) Relational database modeling
a. Functional dependencies and normalizationb. E/R model, UML, and ODL
2) Relational database programminga. Relational algebra, Datalogb. SQL
3) Semistructured data modeling and programminga. XML, DTD, and XML schemab. XPATH, XQuery, XSLT
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1.31.3 Outline of Database-System StudiesOutline of Database-System Studies
4) Database system implementationa. Storage managementb. Query processingc. Transaction processing
5) Modern database system issuesa. Search enginesb. Information integrationc. Data miningd. Data-stream systemse. Peer-to-peer systems
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The End.