Doi vdi cic he truy vin ngdn ngii ty nhien ciia chiing tdi, cic truy van ngdn ngii ty nhien dugc bien doi thanh cac bieu thirc ciia mpt ngdn ngir bieu dien y nghTa truy vin-logic md ti C
Trang 1Ky y^u HQi thto ICT.rda'06 Proceedings of ICT.rda'06 Hanoi May 20
PHEP DICH CAC TRUY VAN LOGIC THANH CAC TRUY > SQL TRONG CAC HE TRUY VAN B A N G NGON N G C TV* NI
Translating the logical queries into SQL q leries
in natural language query systems
Nguyen Kim Anh
Tdm tat
Doi vai cdc hi truy vdn ngdn ngfr lu nhien, cdc truy vdn ngdn ngii lu nhien dugc bien dot thdnh cdc biiu thirc logic Bdi bdo ndy Irinh bdy mgt ky thugt cho phep dich cdc truy vdn iopc ndy thdnh cdc truy vdn SQL vd sau do, mgt he qudn tri ca sd dir lieu (DBMS) se lim tdt cd cdc cdu trd lai ddi vai cdu hdi vdi cdc ky thudt lap ki hogch vd tdi uu hod dgc biet rieng cua no
Abstract
For natural language query systems, natural language queries are transformed internally into logical expressions This paper present one technique to translate the logical queries into SQL queries and then, one relational DBMS is left lofmd all answers to the queries with its own specialised optimization and planning techniques
l.GIOflTHlEU
Giiip may tinh de siir dyng horn, gin giii
vdi con ngudi hom li diiu ma cac nhi lap
trinh va nghien ciru may tinh da, dang vi se
tilp tyc CO ging thyc hifn Ngdn ngir noi la
mpt trong nhiing cich giao tilp thdng dung
vi ty nhien nhit ciia con ngudi Dk giiip miy
tinh giao tilp dupc vdi con ngudi thdng qua
ngdn ngii ndi, chiing ta ein cd cic thinh phin
xu ly ngdn ngCl ty nhien (NLP) Do tinh mip
md, da nghTa trong ngdn ngCl ndi nen cho din
nay, cac hf thong NLP xay dyng dugc diu bj
gidi ban trong mpt miln nhd va chi thdng
djch dugc mpt so lo^i cau nhat djnh
Mpt ITnh vyc mi cic hf thdng NLP cd
thi ip dyng hifu qua li cac hf truy vin co sd
dvt lifu Ly do li cae co sd dii' lifu (CSDL)
thudng phii mpt mien dii nhd nen nhirng ciu
truy vin tiing Vift ve du' lifu cd thi phin tich
dugc bdi mpt hf thong NLP Doi vdi cic he
truy vin ngdn ngii ty nhien ciia chiing tdi, cic
truy van ngdn ngii ty nhien dugc bien doi
thanh cac bieu thirc ciia mpt ngdn ngir bieu
dien y nghTa truy vin-logic md ti ClFR Bai
bio nay dl cip din mpt ky thuit cho phep
djch cic ciu truy vin logic nay thanh cac vin SQL va sau dd, mpt DBMS se tim t cic cau tra idi ddi vdi cau hdi vdi ca thuit lap ke hoach va tdi uu hoa die rieng cua nd Do vay, cic tinh nang ciia DBMS manh cd thi dugc sir dyng khi tr ciu hdi va hf thdng cd thi dl dang phat doi vdi cic co sd dii lifu rit Idn
Npi dung bii bio dupc trinh bay sau: phin 2 md diu vdi mdt so khii nien bin lien quan din vifc xic djnh vi bilu ( ngii nghTa ciia CSDL quan lif Phin 3 ti bay mdt kiln true phic thio cua hf thdng t vin ngdn ngii' ty nhien lim co sd cho p djch cic ciu truy vin logic thanh cac truy SQL Phin 4 trinh uiy phep djch cic cau t vin logic thinh cic truy vin SQL Cudi cu phin 5 trinh biy mpt so vi dy minh ho? phin 6 dua ra mpt vai danh gii vi kit luan
2 MOT S 6 KHAI NIfM CO BAN 2.1.Sordothircthe-lienket
Trong thyc tl, khi thiit kl co sd dir li (CSDL) quan hf cho mpt xi nghifp, chung thudng siir dyng mpt so dd thyc thl-lien 1 bieu dien cau true logic tong thi ciia CSL
Trang 2Proceedings of ICT.rda'06 Hanoi May 20-21,2006
um xl nghifp niy Cic thinh phin co bin
^M so do thyc thl-lien kit la cic thyc
cAc thudc tinh vi cic lien kit Mpt tip
c rill (gd' ^^"^ 8'^n li thyc thi) ki hifu mpt
c4c doi tugng cd cic tinh chit chung va
c gin mpt ten gpi la mpt danh tir Cic tip
thi ^^^^ ^^ ^i"'^ thong qua mdt tip cic
^ p h i t , dupc gpi li cic thupc tinh, dl phan
|h cic die tnmg ciia tip thyc thi Mdi mpt
afic tinh dupc gin mpt ten gpi ciing li mpt
1 tiJ Mpt tip lien kit (gpi dem giin li lien
kl hifu mot tip cic bd ma mdi bp bilu
Uln iTtpt sy ket hgp giira cic thyc the dugc
^ theo bdi lien ket nay Moi lien kit dugc
y n mpt ten gpi li mpt dpng tir Thdng
budng, ngii nghTa cua cic thyc thi, cic thupc
tfnh vi cic lien kit da phin nio dugc phin
^ thdng qua ten gpi ciia chiing Do vay, so
d6 thyc thl-lien kit doi vdi mpt xi Ujghifp co
indt y nghTa quan trpng nhit djnh doi vdi bp
phan tich cii phap ciing nhu bp thong djch
ngjj nghTa dl hiiu nghTa ciia cac eau tru^ van
ijSi vdi CSDL ciia xi nghiep nay va ddi vdi
chiing tdi, so dl thyc the-licn kit doi vdi mpt
xi nghifp CO thi dugc xem nhu la nhirng tri
thurc vl ngii nghTa da dugc biet vl CSDL ma
chiing ta dang xem xet D6ng thdi, so dd thyc
Jfel-lien kit niy ciing dugc siir dyng dl anh xa
vao mo hinh dii lifu quan hf doi vdi xi c
nghifp khi thiit kl co sd dir lifu (CSDL)
quan hf cho xi nghifp niy De don giin,
chung tdi gii thiit ten ciia cic quan hf vi tip
tiiupc tinh ciia chiing dugc dat trimg vdi cic
tfn gpi tuong irng trong so do thyc thl-lien
kit dugc sir dyng khi thyc hifn inh xa
2.2 Logic mo ta CIFR
Cic logic mo ti la cac hf hinh thiire
cho phep bieu dien vi lap luin tren cic ldp
ddi tugng phirc t^p (dugc gpi la cic khii
nifm) vi cic moi quan hf giira chiing (thudng
dugc bieu dien bdi cic quan hf hai ngdi vi
ciing cdn dugc gpi la cic vai trd)
Mpt CO so tri thirc cua logic mo ti gom
cd hai thinh phin:
• TBoxes chua mpt tip cic mo ti khi nifm vi bieu dien cho so do chunj
md hinh hda mien quan tim
• ABoxes la mpt sy thi hifn bd phir ciia so do nay bao gom mpt tap cic khang djnh lien quan din cic ci the cua cic ldp hay cic ci thi c6 quan hi vdi nhau thdng qua cic moi quan bt giiia chung , CIFR li mpt sy md rpng khi ty nhien
cua CIF vdi myc dich bieu dien tryc tilp cic quan hf n-ngoi ma die bift cd y nghTa trong ngir cinh eua chiing toi, bieu diln cic truy van doi vdi mdt co sd dir lifu quan hf
Gia su chiing ta co mpt tap hu'u ban cic khai nifm nguyen to ki hifu bdi A, cic vai tro nguyen td ki hieu bdi P va cic quan hf n-ngoi
ki hifu bdi R Chiing toi sir dung R ki hifu cac vai tro tuy y, C ki hifu cic khai nifm tuy
y va T la khai nifm dinh, 1 la khai nifm diy,
n la phep giao va U la phdp hpp Cac khai nifm vi vai trd dugc xay dyng phii hgp vdi Cli phap sau:
T|±|^|c,nC,|C,UC,hC|VVJ.C|3*.C|(s lP]((s \P-]
VR[U]T, :C,, ,7' :C.|3>?[C/Ir, :C, T :C
Ngir nghTa ciia CIFR, nhu thong thudng dugc cho thong qua ham diln djch 1 = (A,) Die bift, nlu R la mpt quan hf n-ngoi mi tif cic r-vai trd ciia nd li roi (R) = {U|, ,U„} th;
R' li mdt tap cic bp dugc gin nhan cd danj
<U,: d,, ,U„ : d„.>, d diy d,, ,d„ e A' Chung ta vilt r[U] ki hifu gii trj dupe kit hpf vdi U-thanh phin cua bp r
Cic cau true mdi dupc dien djch nhu sau:
R[u,U']=^d,d')e^ xA'\3reR' xl = r{U)Ad' =r{U')]
{>/R\u\T,:Ci, ,T„:Cj={le/S!\^reR'.r{U) = d-^{r[T,]eq', ,rlT„]eCj)]
{3Rlu]T,:q, ,T„:Cj ={ie/s! 3reR' r{U) = d Ar[T,]eC/ A Ar[T„]eCj\
Trang 3Ky ylu HQi thto ICT.rda'06 Proceedings of ICT.rda'06 Hanoi May 20
CIFR-TBoxes dugc djnh nghTa li mpt tip
hihi h^n cic khing djnh bao him C1CC2, d
diy Ci.C: li cic khii nifm tuy y ciia CIFR
CIFR-ABoxes dupc djnh nghTa li mpt tip
hihi han cic khing djnh A(a) vdi a li mpt thi
hifn cua khii nifm nguyen to A, cac khing
djnh P(a,b) vdi (a,b) la mpt thi hifn cua vai
trd nguyen tl P vi cic khing djnh R(U| :
di, ,U„ : d„) vdi <U, : d,, ,Un : d„.>la
mpt thi hifn cua quan hf n-ngdi R
Tinh thoi man ciia khii nifm cung nhu
phep kfo theo logic trong CIFR-TBoxes dugc
djnh nghTa nhu thdng thudng nfn chiing tdi
khong dk cip din trong phin niy niia
3 KlfeN TRUC HE T H 6 N G
Trong phan niy, chiing tdi sS trinh biy
mpt kiln triic phic thio doi vdi hf truy vin
ngdn ngii ty nhien v i mpt so phin tich lien
quan den ph6p djch cic ciu truy vin logic
thinh cic cau truy vin SQL
Theo kiln triic trong hinh 1, cau truy vin
ngdn ngii ty nhien trudc tien dugc phin tich
bdi bp phan tich cii phip Bp phan tich cu
phap tham chilu din tiir diln tiJr vyng dl phan
tich cic tir cd nghia trong cau truy vin ty
nhifn, xic djnh lo^i tir vi timg bude t^o nen
cay Cli phip doi vdi ciu truy vin thdng qua
mpt tip cac luit efl phip Tilp sau dd, ciy
phan tich cu phip kit qui dugc xir ly bdi bd
thdng djch ngii nghTa dl bilu nghTa ciia cau
truy vin va sinh ra cau truy van d?ng logic
Ngdn ngii dugc lya chpn dl bilu diln cac cau
truy vin logic phii cd khi ning md ta hay
djnh nghTa dugc cac tinh chit hay cic diiu
kifn trich rut dugc tir ciu truy vin diu vio
Chiing tdi dk nghj su dyng mpt logic md ti
nhu mpt ngdn ngii trung gian dl bilu diln cic
truy vin logic dudi d^ng mpt bilu thurc logic
mo ti Tilp theo, ciu truy vin logic niy se
dupc djch thinh mpt truy vin SQL mi cd thi
dupc thyc hifn bdi mpt phin mlm hf quin trj
CSDL quan hf nao dd cd h6 trg SQL Bp sinh
cau tri Idi sir dyng cac kit qui ciia truy vin
SQL dl dua ra cau tri Idi cho ngudi sir dyng
Qua phin trinh bay tren, cd thi thiy ring,
bp thdng djch ngii nghTa cd khi ning djch cic
cau truy vin diu vao thinh cic bieu tl nifm eiia logic md ti CIFR-cac cau t logic cd thi thyc hifn dugc Tuy nhii tim ra tit ci cic ciu tri Idi doi vdi mpt trong cic co sd dii lifu Idn khdng dui hifn mdt each hifu qui Do vay, tron tilp theo, chiing tdi chii trpng vao nh djch cic cau truy vin logic thinh cac ti SQL ma cd thi dugc thyc hifn bdi m< mlm hf quan trj CSDL quan hf nio dc trg SQL
Cau truy vin ngon ngpr ty nhien
Bp phan tich cu phap
Cay cu phap
Bp thong dich ngp nghia
Truy vin d^ing logl
BO djch LQL thanh SQL
T n y vin SQL
DBM S quan hf
I KSt qua truy vin
Bf sinh cau tra Idi
I
Tra Idi Hinh 1: Kiln tnic hf thong
4 DJCH CAU TRUY VAN LOGIC THANH TRUY VAN SQL
De bilu diln y nghTa ciia cac truy v
ty nhien, chiing tdi da su dung mpt logic n
ti die bift-CIFR, da dugc gidi thifu troi phin 2.2 va thyc hifn phep djch so dd thi thl-lien kit thanh CIFR-Tboxes va djch n^ dung ciia CSDL quan he thanh CIFI Aboxes
n/;
Trang 4HOi thto ICT.rda'06
4.1 Djch sor do thvc thl-lien ket thinh
QFR-TBoxes
Trong phin niy, chiing tdi se chi ra ring,
cic ngii nghi^a ^^^^ P^i" ii^h trong so do thyc
thI-liSn kit cd thi dugc nim bit trong CIFR
Adng qua mpt phep djch tir so do thyc
thl-lien kit thanh CIFR-TBoxes
Co sd tri thirc CIFR-TBoxes dupe suy ra
ti^ mft so dd thyc thl-lien ket S dugc xic
djnh nhu sau:
Co sd tri thiic niy chiia mpt khai nifm
nguyen to A doi vdi moi miln gii trj thupc
tinh hay mdi thyc thi A, mpt vai tro nguyen td
P doi vdi mdi thupc tinh P va mdt quan hf
n+m-ngoi R ddi vdi mdi lien kit R n-ngdi
(keo theo n thyc the) co m thupc tinh lien kit
"Tip cac khing djnh bao ham ciia ea sd tri
thirc dupc xac djnh nhu sau:
• Vdi moi cap eac thyc the E, F sao cho E
la-mpt F trong S, chiing ta co khang djnh: E
c F vdi E va F la cac khai nifm nguyen to
irng vdi cac thyc thi E va F
• Vdi mdi thyc thi E co cae thupc tinh A|,
A2, ,AkVdi cic miln Di, D2, ,Dk tuong
iimg, chung ta co khang djnh:
E c VAi.D, n nvAk.Dk n (^i
A,)n n(<iAO
• Vdi moi lien kit n-ngdi R giiia n thyc the
E|, En CO m thupc tinh lien kit
Tl, ,Tm vdi cic miln Di, Da
,Dm , tuong irng, chiing ta cd khang djnh:
Ei c VR [EiJ.T, : D,, ,T„:D„,
4.2 Djch npi dung ciia CSDL quan he
thanh CIFR-ABoxes
Vdi moi miln D chira cic gii trj rdi rac
vi hOu h^n, chung ta co khing djnh: D(d) vdi
d li mpt thi hifn ciia D
4J Djch bieu thirc logic mo ta CIFR thinh
truy vin SQL
Ve mpt nghTa nio do, vifc danh gii mpt
bieu thirc logic md ti hay mpt djnh nghTa khii
nifm cung nhu dinh gii mpt truy van trong
mpt CO sd dii lifu li tim ra ngii nghTa cua no:
Proceedings of ICT.rda'06 Hanoi May 20-21,2006
tip cic ci the dupc ki hifu bdi khii nifm niy trong mpt md hinh Do viy, nlu chiing ta cd the cd cac luit djch tdng quit ddi vdi mdi phep toin trong logic md ti nay vi phep djch doi vdi mdi quan hf, khii nifm vi vai tro nguyen to thi mdt sy md ti nio dd dugc ciu thanh vdi cac phep toan vi cic quan hf, khii nifm vi vai trd nguyen td cd the dugc djch thanh mdt truy vin co sd dii lifu Chiing tdi xii ly mpt each dom giin mdi mpt djnh nghTa khai nifm nhu mdt cay, d dd moi nut tuong iirng vdi mdt bilu thirc eon vi do vay, phep djch dupc thyc hifn tir dudi len
Trudc khi trinh bay qua trinh djch, chung toi gia thiet:
• M6i quan he bilu dien thyc thi dugc bo sung them mpt khoa dai difn Mpt tham chieu nao do den khoa nay dugc thong dich nhu mpt tham chilu din quan hf tuong ling Vi
du, trong co sd dir lieu quin ly hpc tip, chiing toi them cac thupc tinh MaSV va MaGV nhu cac khoa dai difn doi vdi quan hf SV va GV tuong ung
• Moi quan hf bieu dien lien ket dupe bd sung them mpt khoa d^i difn bao gom eac khoi dai difn ciia cic quan hf bieu dien cac thyc thi dugc keo theo bdi lien kit niy Vi
dy, khoi d^ii difn cua HudngDan dugc hinh thanh bdi vifc nhom MaSV vi MaGV thanh (MaSV, MiGV)
Phep djch cic bilu thirc khai nifm dugc
ki hifu bdi ham SL.Cic luit djch tong quit ddi vdi cic phep toan ciia logic mo ti:
• Vdi moi khii nifm nguyin td tucmg iing vdi mpt hing D thi SL(D) = D
• Vdi mdi khii nifm nguyin to tucmg irng vdi mdt thyc the E thi
SL(E) = SELECT Kg FROM E
• Khai niem rdng thi SL(±) = 0
• Vdi moi thupc tinh A ciia thyc thi E thi SL(3A.D) = SELECT KE FROM E WHERE A = SL(D)
• Vdi moi thupc tinh A cua thyc thi E vi quan hf so sanh S thi SL(3AoSoD) = SELECT
KE F R O M E WHERE A S' SL(D) trong do
Trang 5Kyy^u HQi thto ICT.rda'06 Proceedings of ICT.rda'06 Hanoi May
S' li phfp djch cic quan hf so sinh thinh cic
phfp toan so sanh trong ngdn ngir SQL
• Vdi moi lifn kit n-ngdi R giiia n thyc thi
E|, , E„ cd m thupc tinh lien kit
SL(3R [Ei].T, : C,, Tk : Ck, Tk., :
Dk+l , Tm : Dm) =
SELECT KB FROM R, C, Ck
WHERE Tk+, = SL(Dk+,) AND AND T™ =
SL(DJ AND KTI DSf SL(C,) AND AND
KTi,INSL(Ck)
• Vdi moi quan hf R[E,, Ej] thi SL(3R.C)
= SELECT KEI FROM R, C WHERE KT2 IN
SL(C)
• Vdi mdi quan hf R[E,, E2] thi
SL(3R.^C) = SELECT KE, FROM R, C
WHERE KT7 NOT IN SL(C)
• C, U C2 thi SL (CU C2 ) = SL (Cl)
UNION SL(C2)
• C, n C2 thi SL (C,n C2 ) = SL (Cl)
INTERSECT SUCj )
• C, n -C2 thi SL (C,n -C2 ) = SL (CI)
MINUS SL(C2)
Mfnh de 1: Cac luit dich t6ng quit d
tren cho phfp bio toin ngCl nghTa ciia cic
phep toin trong logic md ti CIFR
Chirng minh: Cd thi dl ding kiim tra
ngii nghTa cua cic ph6p toin trong logic md
ti CIFR dugc cho thdng qua him diln djch I
= (A', ') li trung vdi kit qui ciia cic lfnh truy
vin SQL tuong dng thdng qua him djch SL
Chii y, cic ph6p toin khic ciia logic md ti
CIFR cd thi dugc biln doi thinh cic phep
toin d tren
Sau khi djch cic bilu thirc logic md ti
CIFR thinh truy van SQL, chiing ta cd thi
thyc hifn mpt s6 xiir ly don giin dl t6i uu sy
thyc hifn cic ciu truy vin nay
4.4 Tinh an toin ciia cac bieu thirc logic
mo ta CIFR
Khi mpt bilu thuc logic md ta dugc
djch thanh mpt truy vin SQL tuong duong
chi chiia cic quan hf dugc luu trir trong co sd
dii lifu, diiu quan trpng la phii kiim tra tinh
an toan ciia truy vin Mpt truy vin,' dugc xem li an toin nlu vifc tri Id niy khdng keo theo tra ciru nhung khdng thich ding doi vdi truy vin
la miu chot dl h^m che ph^m vi tinh mdt truy vin Phep dich cua chiin, thyc hifn ddi vdi cac truy vin an toil
D I giup cho viec xac djnh mdt doi vdi cic bilu thirc logic md ti, c dua ra khii nifm mien ciia cic bieu tl cich tryc giic, mien ciia mpt bieu th hifu li dom(P), la tip tit ci cac gia diam chilu din bdi P Chiing ta < nghTa:
Dinh nghia 1: Cho mpt co sd tri tl
chiing ta ki hifu E, B, H la cac kh nguyen to tuong irng vdi thyc thi, kie
vi hang cdn R la mpt quan hf hai ngdi
vi C2 va R la quan hf n-ngdi Khi dd ts dom(E, KB) = Ins(E,KB)
dom(R, KB) = Ins(R,KB) dom(B, KB) = 0
dom(H, KB) = H dom(R, KB) = dom(C,, KB) u dom(C2, dom(3R.C, KB) = dom(3R.-C, Kl dom(R, KB) u dom(C, KB)
dom(3R [Ei].T,: C,, , Tk: Ck, Tk., :
Tm : Dm, KB) = dom(R, KB) u"'!^, dom(Ci, KB)
dom(C,U C2, KB) = dom(C, U C2, K
dom(C, n -Cz, KB) = dom(C,, KB) u dom(C2, KB) Chii y : Ham Ins xac djnh tap cac hifn trong KB
Dinh nghia 2: Mpt truy vin Q li an 1
doi vdi mpt co sd tri thirc nao dd nlu Ans(Q, KB) c dom(Q, KB), cd nghT; cau tri Idi ddi vdi Q dugc lay ra tir mien
nd
Tir djnh nghTa 1 va 2, mfnh dl sau the dugc chi ra thdng qua phep qui nap d gian theo kich thudc cua mpt truy vin
n o
Trang 6H6i thto ICT.rda'06
Mf i>i> ^^ ^- ^^^ ^^"^^ ^'^^" ^^"'^ s'^ ^'^y
y ^ dii vdi mpt truy vin an toin Q chi cin
kiljn tra cic ci thi trong dom(Q, KB) dl tinh
join ciu tri Idi
D I thiy, nlu Q li mpt bilu thuc khai
nifm thi Q la an toin nlu no cd dang ± , E (E
U thyc thi), 3R.C v i (3R [EJ.T,: C,, , Tk:
Ck, Tk+i : Dk+i, •- Tm: Dm va nd la khdng an
toin nlu nd cd dang T.-'E, VR.C hay <1 R
Mpt phep hpi li an toan nlu va chi nlu it nhit
oipt trong cic thanh phin hpi ciia nd la an
toin Mpt phep tuyen la an toin neu v i chi
neu tit ci cic thanh phin tuyen ciia nd la an
toin Chu y ring, theo djnh nghTa niy, mpt
bilu thirc khii nifm la an toan nlu v i chi nlu
phii djnh ciia nd la khdng an toan
5 MOT S 6 v i DV MINH HOA
• Hay dua ra ten cac sinh vien d Ha Npi
vi sinh sau nim 85: TenSV la thupc tinh cin
dua ra vi bilu thirc logic mo ta li :
BDjaChioHiNpi U 3 NamSinhoLdnHcmoSS
Kit qui djch: SELECT M3SV FROM SV
WHERE DjaChi = 'HaNpi'
INTERSECT
SELECT MaSV FROM SV WHERE
NimSinh>85
Ciu truy van SQL : SELECT TenSV FROM
SV WHERE DjaChi = 'HiNpi'
AND NimSinh>85
• Cho biet ten cic giing vien chi day mon
Co sd dii lifu hay mdn Hf quin trj CSDL
GV n VD?y[GV, MdnHpc]oTenMdno(Co sd
dir lieu U Hf quin trj CSDL)
Kit qui djch: SELECT MaGV FROM GV
MINUS
SELECT MiGV FROM D?iy, MonHpc
WHERE D?y.MaM = MdnHpc.MaM
AND TenMdn NOT IN ('Co sd dtl lifu',
'Hf quin tn CSDL')
a u truy vin SQL : SELECT TenGV FROM
GV WHERE MaGV IN
(SELECT MiGV FROM GV
Proceedings of ICT.rda'06 Hanoi May 20-21.2006
MINUS SELECT MaGV FROM Day, MdnHpc WHERE Day.MaM =M6nHpc.MaM AND
TenMon o 'Co sd dir lifu' AND TenMdn o 'Hf quin trj CSDL')
• Cho biet cic sinh vien ciia giang vien A:
Hf xic djnh dupc 2 dudng dan giiia SV va
G V l a :
1 SV <Hpc> MonHpc <Day> GV vi
2 SV <HudngDin> GV
Ngudi su dung se dupc hoi de lya chpn dudng din phii hpp:
1 3 Hpc[SV, MonHpc] „ Day[M6nHpc, GV] o TenGV.A
2 3 HudngDin [SV, GV] o TenGV.A Ket qui djch:
1 SELECT MaSV FROM Hpc, Day, GV WHERE Hpc.MaM = Day.MaM AND Day.MaGV = GV.MaGV AND TenGV = 'A'
2 SELECT MaSV FROM HudngDin, GV WHERE HudngDin.MaGV = GV.MiGV AND TenGV = 'A'
Ciu Uiiy vin SQL :
1 SELECT * FROM SV WHERE MaSV
IN (SELECT MiSV FROM Hpe, D^y, GV WHERE Hpc.MaM = Day.MaM AND Day.MaGV = GV.MaGV AND TenGV = 'A')
2 SELECT * FROM SV WHERE MaSV
IN (SELECT MaSV FROM HudngDan, GV WHERE HudngDin.MaGV = GV.MaGV AND TenGV = ' A ' )
6 DANH GIA VA KET LUAN
Chiing tdi da tiln hanh cii dat thiir nghifm mpt hf truy vin ngdn ngii ty nhien tiing Vift ddi vdi CSDL Quin ly hpc tap mpt khoa ciia trudng Dai hpc Bich khoa Hf thong cai dat
da dip irng dugc cac yeu ciu va myc tieu de
ra doi vdi mpt hf thdng truy vin ngon ngir ty nhien Tuy nhien, hifu qui ciia hf thong phy
Trang 7Ky yhi HQi thto ICT.rda'06 Proceedings ofICT.rda'06 Hanoi May
thupc rit nhilu vao von tvr vyng ma ta dua
vio Diy chinh la khd khin Idn nhit vi ciing
la vin dl co bin eua bit 1^ hf thdng xir ly
ngdn ngii ty nhien nio - sy hieu bilt cua nd ve
CSDL cy thi
Theo dinh gii ciia chung tdi, cich tiep
can djch cic cau truy vin ty nhien tieng Vift
dupc gidi thifu trong bii niy thinh mpt bilu
thiic logic md ti la rit cd triin vpng Cau truy
van d dang logic nay khi ty nhien va rit gin
vdi cau truy vin ty nhien Horn nila, sir dyng
khi nang lip luin ciia hf logic md ti, chung ta
cd the djch dugc cic truy vin khdng diy dii
thdng tin, khdng rd ring, kiim tra tinh nhit
quin ciia ciu truy vin diu vio vi die bift cd
the ip dyng cic ky thuit toi uu hoi vl ngii
nghTa doi vdi cic ciu truy vin phiic t^p Cach
tiep cin nay die bift phu hgp vdi cac truy vin
tra ciru thong tin vl mpt khii nifm-mpt d^g
truy vin pho biln ddi vdi cic hf CSDL quan
hf
Cuoi cimg, chiing tdi hy vpng ring hf
thong cii dit se dugc cii tien va phit triin
hoin thifn hon niia dl dip irng diy du cic yeu
ciu ciia mpt hf truy vin ngdn ngii ty nhien
tieng Vift vi thyc sy cho phep nhihig ngudi
six dyng khdng dugc dio tao vl Tin hpc cd thi
khai thic tdt cic CSDL
Tii lifu tham khao
1 S.Abiteboul and R Hull, IFO: semandc database model, ACM (4), p 525-565, 1987
2 Androutsopoulos, Interfacing Language Front-End to Relationa Tech Paper no.11, Deptof AI, Edingburgh, 1993
3 D Calvanese, M Lenzerini, D Na for Databases and Information Kluwer, 1998
4 G.D Giacomo, M Lenzerini, I Logic with inverse roles, restrictions, and n-ary relations In the 4th European Workshop on Lo
1994, pp 332-346
5 G.G Hendrix et all Developing language interface to complex da TODS,3(3),p 105-147, 1978
6 J.S Kaplan, Designing a portabl language database query system, AC!
9 (I), p 1-19,1984
7 D.L Waltz, An English language answering system for a large i database, Comm ACM, 21(7), p
1978
Ve tac gia Can bf giing d^y - Khoa Cong nghf th trudng Dai hpc Bich khoa Ha npi