TRUONG D,;J HQC T6NG HQP TP. HO CHi MINH
0Jro
NguOithvc hi~n Nguyen Hi$p Doan
De tili
Mat so cai bien tren ma hinh Dexter
.
ChuyenngilnhTin hoc
.
LUANVANTHAC si KHOA HOC
. . .
Nglioi hlidng dan 1's Dong'Thi Bich Thuy
THANH PHO fiG ~H(, MINH - 1997
?
LO1 CAM TA
.
'§>G~
Toi xin chan thanh earn dn Tien si Dang Thj Bich Thuy, ngu'oi d3:t~n
tinh hu'ang clanva dQngvien Wi hoan thanh lu~n van.
Xin goi Wi earn dn den tat ca cae b~n dang nghi~p d3:giup do va dang
gap
ykien giup toi hoan thanh de tai nay.
Toi xin bay to long biet dn doi vai cha rnt;, cae anh chi em va cae b~n
than d3:khuyen khich Wi trong qua trinh th\fc hi~n de tai.
Tp Ha Chi Minh, ngay 19/6/1997
Nguyen Hi~pDoan
MT)C LT)C
TOM TAT 3
CHUONG1 : lit CO Sa DU LIeU HYPERMEDIA 4
1-Md DAD """"""""""""" 5
Ll - Khai ni~m va-cac h~ hypertext, hypennedia, multimedia 5
L2- Nhilng ling dpng cua h~ thong hypennedia 5

11-$ THONGCSDL HYPERMEDIA 6
IL 1-Djnh nghla 6
IL2-D{ictrungcuam9t h~llMDB ; 6
IL3- Cac khai ni~m cd ban trongllMDB 7
IL4- Cacyeu diu dOl v(jim9t mo hinh llMDB 7
111-WORLDWIDEWEB(WWW) 8
IlL 1-Ljch su WWW 8
IIL2- Ngon ngil'HTML 8
IIL3- WWW vah~ CSDL hypennedia 9
N - MVc TIEDDETAl: 10
CHUONG2: M(n s6 MO HINH DU LI:E;UHYPERMEDIA 11
1-MOHINHDEXTER 12
L1- Tilng 1u'utril' 12
L2- Tilng bell trong : 13
L3- Tilng thl/c hi~n 14
L4- M{itphfin cach giil'atfi'ngbell trong va tfi'ng1u'utril' 14
L5- M{itphfin cach giil'atfi'ng1u'utril'va tfi'ngthl/chi~n 14
L6- Link 15
L 7-Anchor 17
L8- Composite component 17
II - Mo HINHAMSTERDAM 18
ILl- Gi(jithi~u 18
IL2- Kenh tr1nhdiln 18
IL3- Cac mOllien h~ thiligian 19
IL4- Sl/ tong hc;lpcac composite component 19
IL5- Ngil'canh cua link 20
III- Mo HINHVILAS-SATIDSINGKORAPOOM 23
IlL 1- Cac dOltllc;lngcd ban 24
IIL2- Dieu khien dong b9 hoa browse 26
TTTf A A' A , ~ A ,

CnuONG 3: MQT SO N~N XET VE MO HINH HMDB 28
1-MC5DAD 29
II- ANCHOR : 29
IL1-Djnh nghla anchor 29
1
112- N(Hdung anchor 30
113- Thong tin trlnh diln cila anchor 3]
114- Anchor Gang1a component """"""""""""""""""""""""""""""""""""""""" 32
115- Anchor vagiao di~n ngu'aidung 33
111-COMPOSITECOMPONENT 33
IV-ANCHOR TRONG COMPOSITE COMPONENT 35
V- LINK 37
V.1- Link va anchor khong danh dffu 37
v.2- cffu truc cilalink component 37
V.3- Cac link khong chllt " 39
V.4- Link cam ngil canh 40
v.5- Chieu dai media 42
CmJONG 4- MO HINH DEXTER CAI TIEN 45
I- DAN NHAP 45
II- BE XUATCACTHAYDOl TRONGMOHINHDEXTER 45
11] - Tinh md cila h~ thong." "; 45
17.2 Kh
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di
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dilli

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45
. - anang 'leu en va en Ll.et yUcuamo LllLue xuat ."
111-CACTHANHPHANCUAMOHINH 46
IV- Kientruc h~ thong CSDL hypermedia theo mo hinh cJi tien 49
CmJONG 5 : MOT s6 CAI D~ T CHV YEU TRONG MO IDNH HMDB 50
I - CArDATTANGLVU TRU 51
11- Bllt van dJ 51
12- Phan tfch 51
II - CArDATVI~CTHVcHI~NMOTGIAOTAC
" 56
111- Bllt van de: 56
112- Phan tfch 56
HlfONG PHA T TRn~N MO HINH CSDL HYPERMEDIA 60
'A ?
TAl LII::U THAM KHA 0 61
2
Chlidng 1 : H~ cd sd dfi li~u hypermedia
Vi~c phcit tri€n cae phuong ti~n nghe nhln va ky thui;tttruy€n thong di'i

d~n d€n slf hlnh thanh World Wide Web. Tuy vi;ty,ling dlJ.ngchu y€u cua
Web chi la phan ph6i thong tin. Vi~c t(;lOcae tdnh di6n con kh6 khan va
vi~c lien k€t diI li~u chua mang tinh ch~t che cao.
Ph~n nay tdnh bay mQt quan di€m v€ vi~c dinh nghIa va mQt so' khai
ni~m co ban trong CSDL hypermedia.
4
? "
I-Mddfiu
1.1 - Khai ni~m v~ cae h~ hypertext, hypermedia, multimedia
. Hypertext la mQt van ban c6 th€ truy xua't khong tuye'n tinh. Van ban du'Qct6
chlic thanh cac chu de rieng bil$t,va ngu'oi dung c6 th€ d~ dang chuy€n tu chu de
nay sang chu de khac ma khong dn phai dQctugn t1ftu tren xu6ng du'ai. Cach t6
chlic nhu' V?yra't thich hQpcho vil$ctruy xua'tthong tin tren may tinh.
. Multimedia t?P trung VaGnhung phu'ang til$ntruyen thong khong chi la van ban
ma con la am thanh, phim, Cac media se du'Qctrlnh di~n rhea mQtthli t1ftu'ang
quail vai nhau tuy rhea s~p xe'p cua ngu'oibien so~n.
. Hypermedia la hl$ th6ng khong nhung cho phep dieu hu'ang rhea ca'u truc qua
su6t cac tai lil$u, ma con cho phep nh6m nhieu media l~i, t~o thanh mQt trlnh
di~n.
1.2-Nhung ti'ngd\lng cua h~ th6ng hypermedia
1) Giup lam vil$clien t\lCrhea ludng suy nghI.
Theo cach so~n thao truyen th6ng, tac gia phai phac thao cac net chinh rdi mai
phar tri€n chi tie't. Khi cong vil$cphar tri€n, tac gia se kh6 rhea d6i dgy du s1fphar
tri€n cac ytu'dng, cling nhu' s1flien hl$giua cac y tu'dng vai nhau.
B~ng cong C\lhypermedia, ta c6 th€ phar tri€n chi tie't cac y tu'dng tru'ac va d~t
trong cac chu de rieng bil$t.Sail d6 lien ke't cac chu de l~i vai nhau.
2) HI$th6ng trQgiup
Hypermedia giup ngu'oi dung tlm kie'm thong tin nhanh ch6ng va tha'y ngay cac
thong tin lien hl$ dn thie't khac. Han nua, do hypermedia c6 th€ t6ng hQp cac lo~i
thong tin khac nhau nhu'am thanh, phim, nen c6 th€ dung lam cac chu'ang trlnh d~y

hQc,sach tham khao, tu di€n, quang cao va ban san philm
3) Duy trl s1flien Wctrong cong vil$c
Hypermedia la mQt hl$ th6ng md, cho phep ngu'oi dung rich hQp cac ling d\lng
mai, cac d~ng thong tin mai VaGhl$th6ng va lien ke't chung l~i vai nhau. Trong moi
tru'ong hypermedia, ngu'oi dung c6 th€ sa d\lng nhieu ling d\lng khac nhau cho cung
mQtcong vil$c.
4) T~o prototype
Hypermedia du'Qcdung d€ t~o cac prototype giao dil$n mQt cach nhanh ch6ng.
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II- H~ th6ng CSDL hypermedia
11.1-Dinh nghia
H~ co sd dli li~u hypermedia (HMDB) bao g8m cac qua tdnh t~o, hill tm, truy xua't
va xU'ly cac dli li~u (nhu' van ban, hlnh anh, bang bieu, ban d8, ) d d~ng di~n tU'.
Ngoai cac d~ng dli li~u "tInh" nhu' tn3n, h~ th6ng cling h6 trQ cac d~ng dli li~u
"dQng" (co mang ye'u to'thai gian) nhu'ho~t hlnh, am thanh, phim,
Tu'tu'dng chu ye'u cua mQtHMDB la t6 chU'cdli li~u mQteach phi tuye'n. Tli mQtdli
li~u, ngu'ai dung co the lc1ntheo cac link de truy xua't cac dli li~u khac. Trong HMDB,
mQtdli li~u co the la mQtt~p hQpco ca'utruc cua cac dli li~u khac.
Component 2
Component 1
moh 1 -Minh ho~ v~ hypermedia
11.2-Dijc tru'ng ciia m{)t h~ HMDB
. Thay cho cac mfiu tin (record) va cac t~p tin (file), cac component va link la
nhling ca'utruc co ban cua h~ th6ng.
. Thay VI du'Qc ca'u t~o tli cac thuQc tinh, mQt component du'Qc xem nhu la mQt d6i
tuQngthuQcvao mQtlap nha'tdinh nao do.
. Cac component du'Qcke't n6i vdi nhau nhu'mQtm~ng khong h~n che'.
. Vi~c xem nhanh la mQt yeti cc1ub~t buQc cua ht? th6ng. Nghla la ngu'ai dung co
the di chuyen qua l~i gilia cac component thong qua cac link de duyt?t toan bQ ht?
th6ng.

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11.3-Cae kbai ni~m cd ban trong HMDB
Atomic component: la mQt du li~u d d<;mgma h~ th6ng c6 th~ bi~u di6n no mQt
cach dQcl?p.
Anchor: la mQtphc1ncua nQidung component.
Link: la lien ke't du'c;lct(;lOra giua cac anchor. MQt link gdm danh sach cac con tro chi
de'n cac anchor. M6i con tro c6 hu'ang va nQidung rieng cua n6. M6i component co
mQt danh sach cac anchor rieng cua n6. M6i anchor c6 mQtdanh dinh d~ phan bi~t
vai cac anchor khac trong cling component vai n6. MQt link tham chie'u de'n mQt
anchor thong qua C?p(component identifier, anchor identifier).
Composite component: la component du'c;lcxay dlfng tu cac component khac
(atomic ho?c composite) va cac link. H~ th6ng d6i xii' vai cac composite component
hoan loan gi6ng nhu' cac atomic component. Cac composite component khong du'c;lc
chua chinh n6 mQtcach tIVctie'p ho?c gian tie'p.
11.4-Cae yell eftudol voi mQtmo blob HMDB
Theo Vilas Wuwongse va Satid Singkorapoom [1], mo h'inh HMDB phai thoa cae yell
cc1usail:
1. C6 kha nang tich hc;lpcac ki~u du li~u khac nhau vao h~ th6ng.
2. C6 kha nang mo ta cac thlfc th~ c6 ca'utruc cao.
3. C6 slf phan bi~t giua ca'u truc bell trong va slf bi~u hi~n bell ngoai cua cac d6i
tu'c;lng.
4. Co co ca'ut6ng hc;lpthich dang va tin C?y d~ nh6m cac d6i tu'c;lngvao mQtthlfc th~
. / .A
0 muc quail lllym.
5. Phai c6 nhung cach di6n dich khac nhau cua cac m6i quail h~ giua nhung miiu
thong tin. M6i quail h~ phi ngu canh (trong d6 cac d?c tinh cua d6i tu'c;lngtham chie'u
dQcl?p vai d6i tu'c;lngngudn), m6i quail h~ cam ngu canh (trong d6 cac d?c tinh cua
d6i tu'c;lngtham chie'u n~m trong ngu canh d6i tu'c;lngngudn) va m6i quail h~ chua
dl;l'ng(cho bie't cac d6i tu'c;lngca'uthanh d6i tu'c;lngngudn)
6. Phai c6 co ca'u h6 trc;lcho vi~c xem t6ng quat co sd du li~u. Ngu'oi sii'dl,mgHMDB

dn co cac ti~n ich cho phep hQquet qua mQtco sd du li~u mQtcach hi~u qua va theo
nhieu phu'ong thuc khac nhau.
7. Co kha nang t(;lOva dieu khi6n cac phien ban cua cac miiu thong tin. Cac d6i
tu'c;5ngdu li~u thu'ong xuyen bi thay d6i. Vi the' vi~c quail ly phien ban la cc1nthie't
trong vi~c phat tri~n du li~u.
8. Mo hlnh phai h6 trc;lcho kha nang khai tri~n va sii'ad6i. Cac quail ni~m t6ng quat
cua mo hlnh khong bie't de'n ngu nghla cua tung thlfc th~ chuyen bi~t. Do d6 ngu'oi sii'
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dvng se khai tri€n mo hlnh VOlcac chilc nang mOlhay saa d6i cac chilc nang dang co
d€ thich hQp hon VOlcac yeti du ling dvng cua hQ.
9. Khi t<;10mQtd6i tu'Qngtu nhung d6i tu'Qngkhac, h~ th6ng phai co mQtco ch€ bao
dam cho vi~c dlu thanh khong bi I?p vang.
10. Cffnco sv h6 trQve khoang nhln co sd du Ii~u, chi cling dlp nhung phffn thong tin
va thao tac du d€ ngu'oi sa dvng hoan thanh cong vi~c cua hQ.
Theo Halasz [2], h~ th6ng can phai cha'p nhi;lncac d<;1ngdu Ii~u sail :
. Computed component: du li~u co nQi dung Ia k€t qua cua mQt truy vffn tren
HMDB. Khi do, nQidung du Ii~u Ia mQtti;lpcac composite va link.
. Virtual component: du Ii~u chi co nQi dung vao hie thi hanh. NQi dung du li~u
khong du'QcIu'u tru trong co sd du Ii~u. Nhu'ng n€u co mQt component khac (link
component) tro vao component Io<;1inay, thi no phai du'QcIu'utru thi;ltSv trong co sd
du li~u.
Ta chu ytha'ycac nghien cUuve HMDBco cac khuynhhu'angsail:
. Du'acac thong tin trinh di~n vao mo hlnh.
. Mo ta thvc th€ d milc dQtrU'utu'Qngcao b~ng cac co cffut6ng hQpva cac d<;1ngcffu
truc du li~u philc t<;1p.
. Mo ta sv ho<;1tdQngcua thvc th€ b~ng cach h6 trQd<;1ngcomponent Ia mQtchu'ong
trinh, query,
III. World Wide Web (WW»J
111.1-Lfch sll'WWW
MQth~ th6ng hypermedia dang du'Qcsa dvng ph6 bien hi~n nay Ia Warld Wide Web,

do Tim va Robert Cailliau du'a ra vao nam 1990. H~ th6ng WWW dva tren ytu'dng
hypertext do Ted Nelson du'ara nam 1965.
Co th€ coi WWW Ia mQtti;lpcac ti~n ich giup ngu'oi sa dvng t<;10ra cac trang du li~u
da phu'ong ti~n va phat hanh !en Internet. -ang dvng chinh cua WEB Ia d€ phan ph6i
thong tin.
111.2- Ngon figii' HTML
HTML (Hypertext Markup Language) Ia ngon ngu so<;1nthao trang du li~u tren
WWW. HTML Ia mQtngon ngu djnh d<;1ng,hay danh da'u (mark-up). MQt ti;lptin van
ban du'Qcdanh dffub~ng cac the (tag) HTML cho phep ngu'oi ta dQcdu'Qcchung b~ng
ffiQtIo<;1iphffn mem gQiIa bQduy~t (browser). The Ia mQtdo<;1nma du'Qcgiai h<;1nbdi
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da'u '<' va '>'.
HTML khong mo ta trang tai li~u rhea tung phc1ntii' nhu vi tri, kich co, mati s~c,
NguQc l<;1i,HTML chi gall the cho nQidung t~p tin voi nhling thuQc tinh naG do ma
sau do chung duQc xac dinh bdi chuang trlnh duy~t dS xem t~p tin nay. HTML gall
the cho kiSu chli, chen VaGvan ban cac t~p tin dd ho<;1,am thanh, video, 0 va t<;10ra
cac m6i lien ke't hlnh thlic.
Sau nay, cac bQ duy~t con cho phep nhung cac ngon ngli l~p trlnh Java script va
Visual Basic script VaGtrang HTML. Di€u nay cho phep nhling nha so<;1nthao trang
WEB t<;10kha nang Wong tac voi nguoi dung va ke't hQpWEB voi co sd dli li~u. Thttc
te', m6i trang WEB co tuong tac la mQtchuang trlnh con.
BQ duy~t WEB gii'i yeti du va nh~n l<;1idli li~u dn thie't. Dli li~u baa gdm t~p tin
HTML va cac t~p tin dd ho<;1,am thanh, video du'QcgQide'n trong t~p tin HTML. Khi
dli li~u du'Qcnh~n, bQ duy~t dinh hlnh kiSu t~p tin rhea quy dinh cua cac the HTML
da chi ra va hiSn thi trang dli li~u cung voi cac thong tin da phu'ong ti~n di kern. Khi
mQtlien ke't du'QcchQn,mQtyeti du truy c~p de'n mQttrang WEB khac du'Qcgii'ilen
Internet.
Document Object (DocObject) va OLE la nhling cong ngh~ cho phep ngu'oi dung truy
c~p va bien so<;1ntai li~u tu trong bQduy~t.
111.3-WWW va h~ CSDL hypermedia

So sanh h~ th6ng www voi cac yeti du d6i voi mQth~ CSDL hypermedia (11.4),ta
co cac nh~n xet sau :
. Ung dvng chu ye'u cua WWW la hill trU,lien ke't va phan ph6i thong tin. Trang dli
li~u WEB la'y n€n tang la mQt van ban, tu do chen them cac media khac VaG.Cac
ngon ngli Java va Visual Basic du'Qc nhung VaG HTML dS tang kha nang trlnh
di~n cua trang dli li~u. Nhu'ng di€u nay lam vi~c so<;1nthao trang WEB trd nen
phlic t<;1Pd6i voi ngu'oi so<;1nthao VIthong tin trlnh di~n, phu'ong thlic trlnh di~n va
nQi dung hoa l~n VaGnhau.
. Ngon ngli co ban trong WEB la HTML. VI HTML la mQtngon ngli dinh d<;1ng,do
do trong WEB khong thS thttc hi~n vi~c ke'thua l<;1icac trlnh di~n da co.
. Vi~c du'a them cac tinh nang moi va cac d<;1ngmedia khac VaG,da lam cac bQ
duy~t lien tvc phat triSn. Nhu'ng chinh di€u nay lam h<;1nche' kha nang phat tri€n
cua h~ th6ng. BQduy~t khong th€ la mQtling dvng v<;1nnang du'Qc.
. Cac lien ke't tren WEB la cac lien ke't mQt-mQtva la cac lien ke't thv dQng. Thttc
te', lien ke't co th€ la nhi€u dc1uva la mQtco che'tich cttc trong vi~c nh~n va xii'ly
thong tin.
. WWW khong xac dinh khoang nhln d6i voi cac trang dli li~u hoi;1ccac bQ ph~n
cua trang dli li~u.
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IV. Muc lieu de'tAi :
.
.
v~ mijt me')hinh
Lu?n van se khao sat mQt s6 mo hinh CSDL hypermedia. Tren cd sd phan tich u'u
khuyet di€m cac mo hinh nay, lu~n van se de xua't mQt s6 cai tieD tren mo hinh
Dexter.
Cac cai tieD chu yeu la d€ t~o kha Dangd€ bQduy~t co th€ tich hQp cac thanh ph§n
ngoai ma khong dn phai thay d6i cac trlnh server hay trinh duy~t. Cac thanh ph§n
ngoai nay co chU'cDangtrinh dieDcac d~ng media mai duQcdua vao h~ th6ng.
Ngoai ra cac cai tieD con giilp cho vi~c t6ng hQp cac component duQc linh dQng,

phong phil hdn.
. V~mij.tcai dij.t
Chudng trinh cai d~t se dung cd che MDI cua Windows d€ mo phong ca'u hinh
Client/Server. Dieu nay se cho phep sv chuy€n d6i de dang trinh cai d~t sang cac
trinh Server va Client thvc sv.
Moi truong l~p trinh la Borland C 4.5. Trinh cai d~t duQCviet d d,~mghuang d6i
tuQng. Theo mo hinh de xua't, cac thanh ph§n bi€u dieD cac d',lOgmedia se la cac
thanh ph§n bell ngoai duQc tich hQp vao h~ th6ng. D€ thu~n ti~n cho vi~c t6ng hQp
cac thanh ph§n mai tITcac cac thanh ph§n da co, cac thanh ph§n tich hQp ding duQc
cai d~t thanh cac d6i tuQng.
Server se duQc cai d~t la ndi lu'utru va cling ca'p cac d6i tuQng media, cac thong tin
roo ta d6i tuQng media va cac thong tin lien ket cac d6i tuQng do. Client la trinh v~n
d~ng cac thanh ph§n tich hQpd€ trinh dieD cac d6i tuQngduQccling ca'ptITserver.
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