Yêu cầu phần mềm

c t yu cu

Gio vin: Nguyn Dng

Email: [email protected]

Ni dung

Khi nim v tm quan trng

Phn loi cc yu cu

Phn tch v xc nh yu cu

c t yu cu

nh dng ti liu yu cu 2

Khi nim v tm quan trng

Xc nh v c t yu cu

L khu k thut u tin ca qu trnh pht trin phn mm. Thiu n khng th tip tc qu trnh

L s phi hp ca nh pht trin v khch hng

N quyt nh cht lng phn mm t c vi chi ph d kin v thi hn cho trc

3

Cc yu cu v mc tiu

Cc yu cu l cc m t tru tng n chi tit v dch v m h thng cung cp cng nh cc rng buc ln s pht trin v hot ng ca n

Mc ch ca cc yu cu:

Lm c s cho vic mi thu (cn c gii thch t pha ch u t)

Lm c s cho vic k hp ng thu (cn v chi tit)

Lm t liu u vo cho thit k v trin khai (cn , chnh xc v khng mu thun)

4

Cc loi yu cu Yu cu ngi s dng

n gin, d hiu Din t bng ngn ng t nhin v s v dch v h

thng cn cung cp v cc rng buc trong hot ng ca n

Dnh cho khch hng

Yu cu h thng

M t chi tit v cc dch v h thng cung cp

Cc c trng h thng cn c

Nh mt hp ng gia khch hng v ch u t

c t phn mm

chi tit lm c s cho vic thit k v trin khai

Dnh cho nh pht trin 5

Yu cu ngi s dng

Nn m t

Yu cu chc nng

Yu cu phi chc nng

D hiu i vi ngi s dng

Khng c kin thc chi tit v k thut/tin hc

Nn c m t bi:

Ngn ng t nhin

u im: D hiu, d s dng

Hn ch:

Khng r rng, thiu chnh xc, nhp nhng

Ln ln gia yu cu chc nng v phi chc nng

Qu mm do (trnh by nhiu cch)

Biu , bng biu 6

Yu cu h thng

L c t chi tit hn yu cu ngi s dng

Phc v c bn cho bc thit k

C th s dng lm mt phn ca hp ng

C th s dng cc m hnh m t

7

Ti liu c t

L cc pht biu chnh thc v h thng cn xy dng

Khng phi l ti liu thit k

Xc nh h thng cn lm g (What?)

Khng tr li cho cu hi nh th no (How?)

8

Ti liu c t

Cc yu cu i vi ti liu c t

c t hnh vi bn ngoi ca h thng

c t cc rng buc ci t

D dng thay i

S dng nh l cng c tham kho khi bo tr

D bo thi gian sng ca h thng

c t tr li cc s kin khng mong i 9

Nhng ngi c yu cu

Ngi dng h thng

Ngi qun l ca khch hng

K s ca khch hng

Nh kin trc h thng

Cc nh pht trin v bo tr phn mm

Yu cu vit ra cn p ng c cc i tng trn

10

Yu cu t nghip v

Cc yu cu chc nng (Function requirement):

M t cc chc nng hay cc dch v m h thng phn mm cn cung cp

Cc yu cu phi chc nng (Non-Function requirement):

M t cc rng buc t ln dch v v qu trnh pht trin h thng (v cht lng, v mi trng, chun s dng, qui trnh pht trin,)

Cc yu cu min/lnh vc ngoi:

Nhng yu cu t ra t min ng dng, phn nh nhng c trng min .

11

Cc yu cu chc nng

M t chc nng hay dch v ca h thng

Chng ph thuc vo:

Loi phn mm s c xy dng

S mong mun ca khch hng

Loi h thng m phn mm tr gip

Mc cc yu cu

Tru tng: h thng lm g?

Chi tit: nhim v c th ca h thng cn thc hin 12

V d

Ngi s dng c th tm kim ti liu da trn cc t kha c trong ti liu hoc tn ti liu

H thng phi c c cc nh dng khc nhau ca ti liu: vn bn (.txt), PDF, Word, Excel,

H thng cn cung cp phng tin hin th d dng cc ti liu t CSDL

13

Cc yu cu phi chc nng

nh ngha cc tnh cht v rng buc ca h thng

Yu cu tin trnh Phng php thit k

Ngn ng lp trnh

Cng c s dng

Thi gian tr li

tin cy

Yu cu v lu tr d liu

Yu cu phi chc nng c th quan trng hn yu cu chc nng. Nu yu cu phi chc nng khng c p ng h thng tr nn v dng 14

Cc yu cu phi chc nng

Yu cu v sn phm:

Tc , tin cy, b nh cn, giao din,

Yu cu v t chc/tin trnh pht trin:

Cc chun p dng, phng php thit k, ngn ng lp trnh, m trnh tin trnh,

Yu cu t bn ngoi:

V chi ph, thi gian, bn quyn, lin kt,

15

Cc loi yu cu phi chc nng

16

V d

Yu cu v sn phm

Ch s dng ti a 256 MB b nh

Yu cu v t chc

Tin trnh phi p ng chun DO178

Yu cu bn ngoi

H thng khng c l thng tin ca khch hng.

17

Tin trnh k ngh yu cu

Cc hot ng ca tin trnh k ngh

Nghin cu kh thi Bo co kh thi

Phn tch, xc nh yu cu M hnh h thng

c t yu cu Cc yu cu c c t

Thm nh yu cu Ti liu yu cu

18

Tin trnh k ngh yu cu

19

Nghin cu kh thi

Nhm tr li cu hi:

C nn pht trin h thng hay khng?

Ni dung nghin cu kh thi tp trung tr li cc cu hi:

H thng c xy dng s gip ch g cho t chc?

H thng s dng cng ngh no, kinh ph bao nhiu, thi gian bao nhiu?

H thng cn phi tch hp vi h thng no ang s dng?

20

Trin khai nghin cu kh thi

Bo co kh thi c vit da trn cc thng tin, bo co thu thp c, nhng nh gi ban u v h thng hin ti v phc tho cc phng n d kin

Cu hi t ra cho ngi ca t chc:

Ci g xy ra nu h thng khng c trin khai?

Nhng vn g cn gii quyt?

H thng c xut gip h nh th no?

Nhng tch hp g cn phi c?

Cng ngh mi l g, k nng g cn c?

Nhng tin ch g cn tr gip t h thng? 21

Phn tch v xc nh yu cu

Lm r:

Phm vi lnh vc ng dng

Cc dch v h thng cn cung cp

Cc rng buc t ln h thng

Bng cch xy dng cc m hnh phn tch (m hnh nghip v ca h thng) lm r cc yu cu trn 22

Nhng kh khn ca phn tch

Khch hng thng m h v yu cu, khng bit r mnh mun g, d ln ln gia yu cu v mong mun

H th hin yu cu theo thut ng ring

Khch hng a dng, cc yu cu c th mu thun nhau

Nhng yu t t chc v chnh sch c th nh hng n yu cu

Yu cu thng mang tnh c th, kh hiu, kh c chun chung.

Cc yu cu thay i trong qu trnh phn tch: mi trng nghip v thay i,

23

Mc tiu, mong mun v yu cu

Mc tiu, mong mun: l ci hng ti

Chng hn: xy dng giao din thn thin vi ngi dng

Yu cu: l ci c th, kim tra c

Chng hn: giao din ha, cc lnh c chn bng thc n hay biu tng

Nhim v ca ngi phn tch l gi m, xc nh ng, y , chnh xc cc yu cu

24

Tin trnh phn tch yu cu

Cc hot ng chnh: Tm hiu min ng dng

Pht hin, thu thp yu cu

Phn loi yu cu

Gii quyt xung t (nu c)

Sp xp u tin cc yu cu

Thm nh yu cu

25

Cc nguyn l

M hnh ha min thng tin:

Xc nh cc thc th d liu (i tng)

Xc nh cc thuc tnh ca chng

Thit lp mi quan h gia cc d liu

M hnh ha chc nng:

Bn cht ca phn mm l bin i thng tin

Xc nh cc chc nng (bin i thng tin)

Xc nh cch thc d liu (thng tin) di chuyn trong h thng (lung d liu)

Xc nh cc tc nhn to v nhn d liu 26

Cc nguyn l

M hnh ha hnh vi

Xc nh cc trng thi ca h thng

Xc nh cc d kin lm thay i hnh vi ca h thng

Phn hoch, lm mn: biu din cc m t cc mc chi tit khc nhau

Lm mn cc m hnh d liu

To cy (biu ) phn r chc nng

Biu din hnh vi cc mc chi tit khc nhau

27

c t yu cu

c t yu cu l m t yu cu mt cch c bit. Yu cu nn c biu din nhiu mc tru tng khc nhau: y , chnh xc dn, nhiu i tng c th c:

Ngi s dng

Nh qun l

Lp trnh vin

K s pht trin v bo tr

28

Cc mc tru tng ca yu cu

Xc nh yu cu:

M t cc dch v m phn mm cung cp

Vit bng ngn ng t nhin

Hng ngi dng

c t yu cu

Ti liu c cu trc (theo m hnh/phng php)

M t y , chnh xc v chi tit yu cu

Dng lm bn hp ng 29

V d: Chc nng kim tra chnh t

nh ra yu cu: Thng bo li chnh t ca vn bn

c t:

Cc li chnh t c gch bn di

Li son tho c gch xanh bn di

Li chnh t

T n khng c trong t in

Li son tho

Tha du cch

Khng vit hoa u cu 30

i hi c t yu cu

y : Mi yu cu ca ngi dng phi c m t

Khng mu thun vi nhau

Chnh xc: Yu cu khng c m h

Ch c hiu theo mt ngha duy nht

C th nh x c t vo chng trnh

Chi ph pht sinh do sa li t nht c th

D thay i:

Thay i c

t nh hng n cc chc nng khc

31

Cc phng php c t

C nhiu phng php:

c t hnh thc

c t bn hnh thc

c t phi hnh thc

c t phi hnh thc:

Bng ngn ng t nhin

Bng bng, s , hnh v ty chn

Khng cht ch, d hiu nhm

Nhiu cch biu din cho mt khi nim

Kh phn hoch, kh sa i 32

c t bn hnh thc

c t da trn m hnh

Khi nim

K php ha

Quy tc biu din

Cc bc xy dng

Gii thch

V d:

M hnh lung d liu

M hnh thc th - mi quan h (ERD)

M hnh d liu quan h

Cc m hnh nghip v, m hnh phn tch hng i tng vi UML 33

c t hnh thc

Biu din m hnh ton hc

Khi nim v k php ton hc

Quy tc khai bo v biu din biu thc

Cc lut biu din biu thc

C th t ng ha gii m hnh

S dng m hnh cho chng minh, kim chng

Kh hiu, kh s dng 34

Thm nh yu cu

Lin quan n vic kim tra tnh ng n, tnh y , tnh nht qun, tnh hin thc v kim tra c ca yu cu. C th tr li c cc cu hi:

Cn nhu cu no ca ngi dng cha k n?

C mu thun g gia cc yu cu?

Chc nng, rng buc g cha k?

C thc hin c khng?

C th kim tra n nh th no? 35

Cc k thut thm nh yu cu

Xem xt li yu cu:

Phn tch mt cch c h thng

Ly kin khch hng

Tin hnh thng xuyn

Lm bn mu

S dng m hnh kh dng

Kim tra tnh thc hin c

To ca kim th (test case)

S dng CASE: kim tra tnh nht qun 36

Phng php xc nh, c t yu cu

M hnh nghip v (Chc nng)

Biu phn r chc nng (FDD)

M hnh ca s dng (use case)

Biu hot ng (Activity Diagram)

Biu chuyn trng thi

M hnh lung d liu (DFD)

Biu thc th mi quan h (ERD) 37

Biu phn r chc nng

FDD Function Decomposition Diagram

Xc nh phm vi ca h thng

Phn hoch chc nng

To nn tng cho thit k kin trc h thng

38

V d:

39

Biu lung d liu

DFD Data Flow Diagram

M t qu trnh x l thng tin nghip v

Biu din cch thc d liu di chuyn, c x l, lu tr trong h thng v trao i vi mi trng

C nhiu mc tru tng khc nhau

Lm c s cu trc phn mm

40

Biu lung d liu

Khi nim

Tc nhn: ngi, t chc, h khc

i tng ngoi h thng

Pht sinh hoc tip nhn d liu/thng tin

Tin trnh: hot ng nghip v

Dy hot ng tc ng ln d liu

Lung d liu: d liu di chuyn

D liu di chuyn t ngun ti ch

Kho d liu: d liu c lu tr

D liu c lu tr mt v tr

41 Tn tc nhn Tn tin trnh

Tn lung d liu

Tn kho

V d: DFD mc 0 bn v tu

42

M hnh thc th mi quan h

43

Tm quan trng ca ERD

Phn tch d liu c lp vi lu tr v x l

Nghin cu phm vi min thng tin

To ra m hnh tru tng hng khch hng (m hnh khi nim), trc quan

Xc nh cc mi quan h mang tnh cu trc gia cc d liu. D dng chuyn sang m hnh thit k 44

Phng php thu thp yu cu

Phng vn

Quan st

iu tra bng bng hi

Nghin cu ti liu

45

Ti liu yu cu

Yu cu:

Ch m t chc nng, rng buc

Khng m t v phng thc ci t

Phi d thay i

Kh xc nh chnh xc, y ngay

Phi qua nhiu bc xt li

46

nh dng ti liu yu cu

Gii thiu: M t s cn thit ca h thng

Thut ng: nh ngha cc khi nim k thut c s dng trong ti liu ny

nh ngha yu cu ngi s dng: yu cu chc nng v phi chc nng

Kin trc h thng

c t yu cu h thng: M t yu cu c bn chi tit hn

M hnh h thng: M hnh i tng, m hnh lung d liu v ng ngha d liu,

Pht trin/thay i ca h thng: Cc gi thit, cc d on v pht trin phn cng, yu cu ngi dng

Ph lc

Ch mc: Ch mc theo ch ci, theo chng, theo chc nng 47

Question

48