Đề cương CSDLĐPT

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cng n tp: C sdliu a phng tinLp: D08HTTT1

Cu 1: Cc loi dliu PT v cch phn loi ? (Kin)Tr li:

- Cc loi d liu PT bao gm:+ D liu vn bn (c hoc khng c cu trc)+ D liu m thanh

+ D liu nh+ D liu video

- Mt s cch phn loi d liu:+ Da trn nh dng vt l+ Da trn mi quan h gia cc d liu PT vi chiu thi gian hay khng gian

Cu 2: Cc c tnh chnh ca dliu PT? (Kin)Tr li:

- Cc c tnh chnh ca d liu PT gm c:+ Dung lng ln (video, audio)+ D liu video v audio c chiu thi gian nn phi c trnh by tc xc

nh+ D liu saudio, images, video c biu din bng chui cc gi tr mu ring

bit, thiu cu trc ngngha my tnh c th tng nhn dng ni dung.

+ Nhiu ng dng PTi hi biu din ng thi nhiu loi d liu PT theochiu thi gian v khng gian ph hp.

+ D liu PT mang nhiu thng tin. Do cn nhiu tham s biu din nidung mt cch ng n

Cu 3: So snh DBMS vi IR? (on)

Tr li:

DBMS IR

- Mt DBMS cha cc bn ghi ccu trc ng nht:

+ Mi bn ghi c c trng bi ccthuc tnh

+ Gi tr ca thuc tnh miu t r rng

- Trong IR, cc bn ghi khng ccu trc, khng c thuc tnh cnh:

+ nh ch mc: keywords, indexterms, doc descriptor

+ To t kha v ch mc ng vai tr

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v y cc bn ghi

- Trong DBMS, vic truy vn thngtin da trn s trng lp tuyt i giacu truy vn v gi tr cc thuc tnh ca

bn ghi

quan trng

- Trong IR, khng i hi trng lptuyi

- S truy vn da trn trng khpgia cc tp thut ng

- S dng cc phng php trnglp xp x hoc tng phn

- Cng 1 term c thc ngha khc

Cu 4: Vai tr ca DBMS v IR trong truy vn thng tin PT? (Kin)Tr li:

Vai tr ca DBMS (H qun trc sd liu) trong truy vn thng tin PT:- Cc h qun trCSDL c pht trin v s dng rng ri i vi d liu c

cu trc- Trong h qun tr CSDL quan h, thng tin c t chc di dng cc bng

v quan h. Cc hng ca bng tngng vi cc n v thng tin hoc bn ghi. Ccct tng ng vi cc thuc tnh

- SQL c s dng thao tc trn CSDL+ V d: create table STUDENT(

Student_id integer,

Name varchar(50),

Address varchar(100))

- Cc thuc tnh trong h qun tr CSDL quan h c kiu cnh v c kch ccnh. H qun tr CSDL quan h ph hp vi vic x l cc d liu kiu ch s vcc xu k t ngn

- Loi d liu ln c di bin i c h trtrong h qun tr CSDL quanh l i tng rng hoc nh phn (BLOB)+ V d: create table STUDENT(

Student_id integer,

Name varchar(50),

Address varchar(100),

Picture BLOB)

- H qun trCSDL hng i tng+ Kt ni cc c im hng i tng vi CSDL quan h

+ Cc i tng c nh ngha theo kiu hng i tng. Mi i tng chacc thuc tnh v phng thc

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+ V d: Create type Image(

Private

Size integer,

Resolution integer,

Content float[],

Public

)

create table STUDENT(

Student_id integer,

Name varchar(50),

Address varchar(100),

Picture IMAGE)

- BLOBs v cc i tng l mt bc tip cn n x l d liu PT- BLOBs ch lu tr d liu c khi lng ln, cn i tng cha cc thuc

tnh n gin dn n mt s yu cu x l truy vn d liu PTnh sau:+ Cc cng c tng hoc bn tng trch chn cc ni dung v c trng cha

trong d liu PT+ Cu trc nh ch mc a chiu xl cc vector c trng+ Cc o tng ng truy vn thng tin PT thay v s dng trng lp chnh

xc

+ Cc h thng con lu tr d liu kch cln, bng tn rng, thi gian thc+ Giao din ngi dng cho php to cu truy vn linh hot trn cc loi d liu

PT khc nhau, biu din d liu PT.

Vai tr ca IR trong truy vn thng tin PT- IR tp trung vo truy vn ti liu vn bn- Cc k thut IR ng vai tr quan trng trong qun l thng tin PT bi:+ Tn ti mt lng ln cc ti liu vn bn cc dng t chc, v dnh th vin.

+ Vn bn c dng ch gii cc loi d liu PT khc- Tuy nhin, vic dng cc k thut IR trong xl thng tin PT c hn ch:+ Vic ch gii l qu trnh th cng, tn thi gian+ Vic ch gii l khng y v mang tnh ch quan+ Cc k thut IR khng th x l cc cu truy vn dng khc vn bn+ Mt vi c im PT kh m t bng vn bn (kt cu nh, hnh th i

tng..)

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Cu 5: Cc kin trc h thng CSDL PT?(Ngha)

Tr li:

a. Kin trc cp lng- Th no l kin trc cp lng+ H qun tr CSDL l 1 h thng gm 1 CSDL v cc thao tc trn CSDL ,

c thit k trn nn tng phn cng, phn mm vi mt kin trc nht nh+ H qun tr CSDL y qun l d liu metadata+ Thnh phn qun l tp tin a phng tin, qun l d liu a phng tin

+ Module tch hp h qun tr CSDL v thnh phn qun l tp tin a phng tin

- u im: Tn dng cc h thng qun l tp tin a phng tin khc nhau qun l d liu

b. Kin trc cp cht- Kin trc cp cht+ H qun tr CSDL y qun l d liu a phng tin v metadata+ H qun tr CSDL l mt MM-DBMS

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- u im: Cc chc nng ca DBMS c th c p dng trn CSDL aphng tin

+ Qun l truy vn+ Qun l giao dch

+ Qun l lu tr+ Qun l bo mt ton vn

c. Kin trc lc - Lc l metadata m t d

liu dpt trong CSDL- M hnh 3 mc lc - Lc ngoi nh ngha cc

cch nhn ca ngi dng i vi CSDL

(video view, audio view)

- Lc khi nim c xydng da trn cc m hnh d liu

- Lc trong: cu trc d liubn trong

- Mi lc c cc cch biudin khc nhau

- Mappings thc hin chuyn it biu din ny sang biu din khc

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d. Kin trc chc nng

e. Kin trc h thng mrng

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f. Kin trc phn tn- Cch m cc i tng c phn tn v kt hp+ Truy vn

+ Giao dch+ Metadata

+ Bo mt+ Ton vn d liu

g. Kin trc lin ng- Client/server (CORBA)- Ba tng (three tier)- Hng thnh phn

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h. Kin trc siu phng tin: h trduyt CSDL theo cc lin kt

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Cu 6: Dliu meta cho CSDL a phng tin? (Phng)

Tr li:

1. nh ngha Metadata- L dng d liu m t v d liu. Trong c sd liu, metadata l cc dngbiu din khc nhau ca cc i tng trong c sd liu. Trong c sd liu quan

h, metadata l cc nh ngha ca bng, ct, c sd liu, view v nhiu i tngkhc. Trong kho d liu, metadata l dng nh ngha d liu nh: bng, ct, mt boco, cc lut doanh nghip hay nhng quy tc bin i. Metadata bao qut tt c cc

phng tin ca kho d liu.- Metadata phi cha nhng thng tin: cu trc ca d liu, thut ton s dng

tng hp d liu, nh xxc nh stng ng d liu tmi trng tc nghipsang kho d liu

2. Vai tr Metadata- Thng tin metadata c cung cp cho php ngi dng cui hiu r hn bn

cht v d liu m hang c v quyt nh s dng mt cch ng n v ph hpd liu.

- Cu trc v ni dung d liu bao gm mt s loi thng tin c bn: Thng tinm t v bn thn d liu metadata; thng tin v d liu m metadata m t; thng tinv c nhn, t chc lin quan n d liu metadata v d liu

3. Cc loi metadata- Metadata cho cc loi phng tin khc nhau- c trng bng mi quan h vi ni dung d liu a phng tin- Metadata c thc trch chn trc tip t d liu a phng tin Metadata cho d liu vn bn- Cha ng thng tin v d liu vn bn- Metadata c lp ni dung:+ Loi d liu vn bn+ S trang

+ nh dng+ Schng, s paragraph mi chng- Metadata ph thuc ni dung: Ni dung cu chuyn, tkha, tiu , tm tt- SGML (standard generalized markup language), XML c s dng gn th

cho cc loi d liu vn bn c th trch chn- Cc th c thc lu trong DBs- D liu text c thc ch gii Metadata cho d liu nh-

S dng d liu text m tnh- Metadata c thc lu trong DBs

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- Metadata c lp/ph thuc ni dung- V d: Bc nh X m ti dng vi rng c v nhng ngi nh trn bi bin Metadata cho d liu m thanh- M hnh ha cho d liu m thanh- Gn th metadata- Trch chn t kha trong th- D liu m thanh c thc ch gii- Metadata c lp/ph thuc ni dung Metadata cho d liu video- M hnh ha cho d liu video- Gn th metadata- Trch chn t kha trong th- D liu video c thc ch gii- Metadata c lp/ph thuc ni dung Metadata cho d liu kt hp- Metadata dng ng b hin th cc loi phng tin4. Cc kha cnh lin quan n Metadata- Ontology cho d liu a phng tin+ Ontology l c t v s khi nim ha+ Dng biu din tri thc chung cho qu trnh cng tc- Ch gii+ Qun l ch gii: trch chn, truy vn, cp nht, tng quan gia cc ch gii v

d liu a phng tin- Cht lng dch v v ngun gc d liu+ chnh xch ca d liu+ Ngun gc ca d liu

5. Qun l Metadata- Truy vn- Cp nht- Bo mt- Trch chn

Cu 7: K thut nh ch mc cho cc loi dliu khc nhau? (. Giang)

Tr li:

- D liu vn bn: da trn t kha. Mt vn bn lun mang cng lc nhiu yut, do vy phi chn mt tkha c ngha rng nhng phi t k t. Khng nn chn

t kha qu di hay qu ngn. La chn t kha cn phi tr li c cu hi: vn bn

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thuc loi no? i tng hng n l ai? Ngi dng dng loi cng cno tmkim?

- D liu nh: da trn t kha, nh- D liu video: da trn t kha, cc nh trch trn tnh- Audio: t kha- Ch gii.

Cu 8: Cc k thut lu trtrong c sdliu a phng tin? (Cc)

Tr li:

- Dng mng cc a r tin- Kin trc lu tr phn cp+ Dng bng tv a quan lu tr di hn, a tlu on bt u ca phng

tin (trban u thp)+ Di chuyn files tbng tra a t khi c yu cu (trban u di gii php

da trn mu s dng, tn s s dng)- Lu tr d liu trn thit b+ Cc tp tin c phn thnh cc blocks+ Cc blocks c lu a theo cc phng php khc nhau

Lu lin tc: Cc block ca file nh v lin tip trn cc block ca a.

u im:dci tNhc im: Tn thi gian khi chn v xa, phn mnh aThch hp cho ng dng ghi mt ln, c nhiu ln.

Lu c rng buc: Tng block ca file cha con tr tr ti block k tipu im: d mrng fileNhc im: c file chm

Lu ri rcDanh sch lin kt, FAT, I-nodes

- Lu tr d liu trn mng a.+ Lu ton bfile a phng tin trn mt a+ Lu file trn cc a khc nhau

+ Lu ton bfile a phng tin trn mt a+ Lu ton bfile a phng tin trn mt a

+ Lu file trn cc a khc nhau+ Cc k thut phn tn cc blocks trn cc a:

Data Striping: Blocks c t chc thnh cc nhm truy cp, cc a ctruy cp ng b

Data interleaving: Cc a khng c truy cp ng b

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Mong mun c kch thc ca blocks bng vi kch thc ca cc n v dliu phng tin logic

- iu a v iu khin tip nhn+ Thit blu tr cn truyn d liu bng vi tc phng tin c biu th pha

client

+ Hot ng a l khng tt nh nn cn c c chiu a duy tr