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Advanced Database Technology

Ho NGUYEN

College of Technology,

Vietnam National University, Hanoi

18 February 2013 Hoa.Nguyen@vnu.edu.vn

Fundamental Notions of Database

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Advanced Database Technology Information Systems Department 2

Definitions

Information system: model about some phenomena in the

world - the Universe of Discourse - (e.g. an organization) retrieves, updates and deletes these facts

derives other facts from existing ones

Data - raw facts/details of the model

DATABASE: A shared collection of logically related data(and a description of this data), designed to meet theorganization needs of an organization

Database Management System (DBMS): software thatenables users to define, create and maintain the databaseand provides controlled access to the database

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Advanced Database Technology Information Systems Department 3

nh ngha

M hnh h thng thng tin v mt s hin tng trong th

gii v tr lun (v d nh mt t chc) truy xut, cp nht v xa cc s kin

ngun gc s kin khc t nhng ci hin

- Nguyn d liu s kin / chi tit ca m hnh

DATABASE: Mt b su tp c chia s d liu mt cchhp l c lin quan (v mt m t d liu ny), c thitk p ng cc t chc nhu cu ca mt t chc

H thng qun l c s d liu (DBMS): phn mm chophp ngi dng nh ngha, to ra v duy tr c s d liuv cung cp kim sot truy cp vo c s d liu

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Advanced Database Technology Information Systems Department 4

Functions of a DBMS

Data storage, retrieval, update

A user-accessible catalog

Transaction support

Concurrency control

Recovery services

Authorization services

Support for data communication

Integrity services

Data independence

Utility services

Lu tr d liu, phc hi,

cp nhtMt danh mc s dngtruy cph tr giao dch

kim sot ng thidch v phc hiy quyn dch vH tr truyn thng dliutnh ton vn dch vd liu c lpdch v tin c

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Advanced Database Technology Information Systems Department 5

Interacting with the DBMSTng tc vi cc DBMS

ApplicationProgramsEnd Users

Database

DBMS

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Components of the DatabaseCc thnh phn ca c s d liu

DDLSTATEMENTS

PRIVILEGEDCOMMANDS

DBA Staff

DDLcompiler

Precompiler

DMLstatements

DMLcompiler

APPLICATIONPROGRAMS

applicationprogrammers

COMPILEDTRANSACTIONS

Host LanguageCompiler

casual users

HIGH-LEVELQUERY

QueryProcessor

Run time

DatabaseProcessor

SystemCatalog/

Data

Dictionary

Concurrency control/Backup/Recovery

Subsystems

STORED DATABASE

DatabaseManager

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Database Manager Components

Authorization control - check authorized to carry out

operation Command processor - control of operation

Integrity checker - updates checked against constraints

Query Optimizer - determine optimal strategy for query

Transaction Manager - controls transaction operations

Scheduler - ensure concurrent operations do not conflict

Recovery Manager - if failure returns to a consistent state

Buffer Manger - transfer of data between memory and CPU Recovery Manager and Buffer Manger often referred to

collectively as Data manager

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Qun l c s d liu thnh phn

Kim sot y quyn - t phng y quyn thc hin hot

ng Lnh x l - kim sot hot ng

Tnh ton vn kim tra - cp nht kim tra i vi cc rngbuc

truy vn ti u xc nh chin lc ti u cho truy vn Giao dch v qun l kim sot cc hot ng giao dch

ln lch m bo hot ng ng thi khng xung t

phc hi qun l - nu tht bi tr v mt nh nc thngnht

m manger- chuyn giao d liu gia b nh v CPU

phc hi qun l v b m mng c thng c gichung l qun l d liu

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Maintaining the Database

This is the task of the DBA:

Maintaining information structure of the database (metadatain the Data Dictionary)

Define user requirements of data usage

Monitor use of database

Determine and optimize storage structure and access

strategies

Define authorization checks

Define strategies for backup and recovery

Define testing procedures and changeover policy

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Duy tr c s d liu

y l nhim v ca DBA:

Duy tr thng tin cu trc ca c s d liu (d liu metatrong t in d liu)

Xc nh yu cu ngi s dng s dng d liu

Mn hnh s dng c s d liu

Xc nh v ti u ha cu trc lu tr v chin lc truycp

Xc nh kim tra y quyn

Xc nh chin lc sao lu v phc hi

Xc nh th tc kim tra v chnh sch chuyn i

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Data Models and SchemasM hnh d liu v lc Data Model

Specifies the allowable logical structures and operations in adatabase. A DBMS operates always according to a specific data

model eg. relational

(M hnh d liu: Ch nh cc cu trc hp l cho php v hot ngtrong mt c s d liu. DBMS chia tay lun lun theo mt m hnh c

th v d nh d liu. quan h) Database Schema (intension)

The description of a database for a particular universe of discourse

which follows the rules layed down by the data model supported by

the target DBMS

(Lc c s d liu (tng thm):Cc m t ca mt c s d liuc th ca mt v tr lun theo cc quy tc layed xung bi m hnhd liu c h tr bi cc DBMS ch)

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01 BOOK02 TITLE PIC X(30)02 AUTHOR_NAME

PIC X(20)

01 BOOK02 TITLE PIC X(30)02 PUBLISH_NAME

PIC X(20)02 YEAR PIC 9(4)

VIEW 1 VIEW 2

BOOKTITLE CHARACTER(30

AUTHOR CHARACTER (20)PUBLISHER CHARACTER(20)YEAR NUMERIC (4)

BOOKSHOP

EXTERNAL LEVEL(individual view)

CONCEPTUAL LEVEL(community view)

INTERNAL LEVEL(storage view)

VIEW 1 VIEW 2

StructuralProperties

& Constraints

LogicalRepresentation

of Stored Records

STORED_BOOK LENGTH=80PREFIX TYPE=BYTE(6)TITLE TYPE=BYTE(30), INDEX=TITLE X

AUTHOR TYPE=BYTE(20)etc

3-levels Architecture3-cp kin trc

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Data Independence

Logical Data Independence: The capacity to change the

conceptual schema without having to change the externalschemas and their application programs .(Hp l d liu clp: kh nng thay i lc khi nim m khng cn

phi thay i cc lc bn ngoi v cc chng trnhng dng ca h)

Physical Data Independence: The capacity to change the

internal schema without having to change the conceptual

schema .(c lp d liu vt l: Kh nng thay i gin ni b m khng cn phi thay i cc lc khi nim.)

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Database Languages

External Level: mc ngoi

Generalized Query Language(DDL + DML)One or more Host Languages

e.g. COBOL, FORTRAN etc

Embedded Sublanguage(DDL + DML)

Application Programming

Specialized Query Language

e.g. forms-driven, graphics-driven, menu-driven etc

End-user Facilities

Data Definition Language (DDL)& Data Manipulation Language (DML)Ngn ng nh ngha d liu (DDL)

Ngn ng thao tc d liu (DML)

Data Definition Language (DDL)

Conceptual Level: Mc Khi nim

Internal Level: Mc trong

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System Catalog

A system catalog contains the description of the database

Often referred to as the 'data dictionary'

For the relational data model the catalog is defined and

interrogated using the same languages that can be used at

the application level (i.e. DDL and DML) - but includes extra

commands The catalog describes:

the basic make up of the data items

base data

views

authorization data

integrity constraints

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danh mc h thng

Mt danh mc h thng cha cc m t ca cc c s d

liu Thng c gi l 'd liu t in

i vi m hnh d liu quan h, danh mc c xc nhv thm vn bng cch s dng cng ngn ng c th

c s dng mc ng dng (tc l DDL v DML) -nhng bao gm cc lnh thm

Danh mc m t:

c bn ca cc mc d liu

c s d liu views

cho php d liu

tnh ton vn rng buc

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Views

A view represents virtual data structures which are derived

from base data structures (Xem Mt i din cho cu trcd liu o m c ngun gc t c s cu trc d liu)

Views permit users to perceive the database in terms of

derived data which correspond exactly to their applications

(Xem cho php ngi s dng cm nhn c s dliu v d liu c ngun gc t tng ng chnh xccho cc ng dng ca h)

Views insulate programmers from base data and enable

changes to definitions of base data without affecting

application programs (Xem cch nhit cc lp trnh vint c s d liu v cho php thay i nh ngha ca cs d liu m khng nh hng n cc chng trnhng dng)

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Example of a View

Title Author Publisher Year

Intro to DB Systems Date Addison-Wesley 1986

Fund. of DB Systems Elmasri Addison-Wesley 1989

London Fields Amis Penguin 1989

100 years of solitude Marquez Picador 1982

The history man Bradbury Arrow Books 1977

BOOK

CREATE VIEW NEW_BOOKAS SELECT TITLE, AUTHOR

FROM BOOKWHERE YEAR>1988

Title Author

Fund. of DB Systems Elmasri

London Fields Amis

NEW_BOOK

at run-time

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History

The first DBMS was designed by Bachman at GE in early

1960sBachman (Turing award 1973).

In 1970 Codd at IBM proposed a new data representationframework called the relational data model.

Codd (Turing Award 1981)

The SQL query for relational databases, developed as part ofIBM's System R project, was standardized in the late 1980s.

SQL-92, was adopted by ANSI (American NationalStandards Institute) and ISO (International Standards

Organization). SQL-1999 added packages for data mining, spatial data, and

text documents SQL2003 : XML, Window functions, and sequences (Not free)

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History

In late 1980s and 1990s, several vendors (e.g. IBM's

DB2, Oracle 8, Informix UDS) have extended theirsystems with the ability to store new data types such as

images and text.

Specialized systems developed fordata warehouses,

consolidating data from several databases.

Entering the Internet Age, a new markup language

XML is proposed for data access through a Web

browser.

As more and more data are collected, companies are

also interested to mine useful information from their

data.