Bai Gian Nhap Mon Ky Nghe Phan Mem

8/2/2019 Bai Gian Nhap Mon Ky Nghe Phan Mem

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I HC THI NGUYNTRNG I HC CNG NGH THNG TIN V TRUYN THNG

KHOA H THNG THNG TIN KINH T

Nguyn Vn HunV Xun Nam

NHP MN K NGH PHN MM

Thi Nguyn, 2011


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LI NI U

Nhp mn K ngh phn mm l mn hc nhm gip cho sinh vin c kin

thc c bn nht trong lnh vc cng ngh phn mm. Ni dng ca mn hc xoay

quanh vn gip sinh vin hnh dung c bc tranh tng th v ngnh cng ngh

phn mm, bao gm qui trnh pht trin, ngha v mi quan lin h ca tng cng

on pht trin, cch thc trnh by ti liu, vai tr ca tng ngi trong qui trnh php

trin. ng thi gii thiu cho sinh vin qu trnh lch s pht trin ca ngnh sinh

vin c hng i tip theo hp l. c bit, gip sinh vin thy c vai tr thc s

ca ngnh cng ngh thng tin trong x hi.

Qua mn hc ny sinh vin c ci nhn khi qut v qui trnh pht trin phn

mm, hiu bit v thc hin cc giai on trong qui trnh trn mt phn mm cth da trn nhng phng php, k thut trong qu trnh thu thp yu cu, phn

tch, thit k v ci t, vit su liu c minh ha c th trong gio trnh.

Mc tiu gio trnh l sinh vin c th hiu c nhng yu cu cng vic cn

phi lm mi giai on ca qui trnh, c th m trch cng vic mt trong

cc giai on lm phn mm trong nhng nhm d n.


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MC LCMc lc ... 1

Chng 1: TNG QUAN V CNG NGH PHN MM .......................................... 3

1. CC KHI NIM C BN........................................................................................ 3

1.1. Phn mm .............................................................................................................. 3

1.1.1. Cc khi nim ................................................................................................. 3

1.1.2. Phn loi ......................................................................................................... 4

1.1.3. Kin trc phn mm ....................................................................................... 4

1.2. Cht lng phn mm ........................................................................................... 6

1.2.1. Tnh ng n ................................................................................................. 6

1.2.2. Tnh tin ha ................................................................................................... 7

1.2.3. Tnh hiu qu .................................................................................................. 7

1.2.4. Tnh tin dng................................................................................................. 8

1.2.5. Tnh tng thch ............................................................................................. 8

1.2.6. Tnh ti s dng .............................................................................................. 8

1.3. K ngh phn mm................................................................................................ 8

1.3.1. S ra i ......................................................................................................... 8

1.3.2. nh ngha ...................................................................................................... 9

1.3.3. i tng nghin cu ................................................................................... 10

2. QUI TRNH CNG NGH PHN MM ................................................................. 11

2.1. Cc bc c bn trong xy dng phn mm ....................................................... 11

2.1.1. Xc nh........................................................................................................ 11

2.1.2. Pht trin....................................................................................................... 11

2.1.3. Bo tr (Vn hnh) ........................................................................................ 12

2.2. Cc qui trnh xy dng phn mm...................................................................... 12

2.2.1. M hnh thc nc ........................................................................................ 12

2.2.2. M hnh bn mu phn mm ....................................................................... 172.2.3. M hnh xon c ........................................................................................... 18

3. CC PHNG PHP XY DNG PHN MM .................................................. 19

3.1. Tng quan ............................................................................................................ 19

3.1.1. Khi nim ..................................................................................................... 19

3.1.2. Phn loi ....................................................................................................... 19

3.2. Cc phng php xy dng phn mm ............................................................... 20

3.2.1. Cch tip cn ................................................................................................ 203.2.2. Cch tin hnh .............................................................................................. 21

4. CNG C V MI TRNG PHT TRIN PHN MM .................................. 24


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4.1. M u................................................................................................................. 24

4.1.1. Khi nim ..................................................................................................... 24

4.2. Phn mm h tr thc hin cc giai on............................................................ 24

4.2.1. Phn mm h tr phn tch ........................................................................... 24

4.2.2. Phn mm h tr thit k.............................................................................. 244.2.3. Phn mm h tr lp trnh ............................................................................ 25

4.2.4. Phn mm h tr kim chng....................................................................... 25

4.3. Phn mm h tr t chc, qun l vic trin khai ............................................... 25

4.3.1. Xy dng phng n .................................................................................... 25

4.3.2. Lp k hoch................................................................................................. 25

Chng 2: PHN TCH V C T YU CU........................................................ 26

1. Tng quan ................................................................................................................... 26

1.1 Qu trnh phn tch ............................................................................................... 26

1.1.1 Phn tch phm vi d n ................................................................................ 26

1.1.2 Phn tch m rng yu cu nghip v ........................................................... 27

1.1.3.Phn tch yu cu bo mt ............................................................................. 28

1.1.4.Phn tch yu cu tc ................................................................................ 30

1.1.5 Phn tch yu cu vn hnh ........................................................................... 31

1.1.6 Phn tch kh nng m rng yu cu............................................................. 32

1.1.7. Phn tch nhng yu cu sn c.................................................................... 32

1.1.8. Phn tch yu t con ngi ........................................................................... 33

1.1.9. Phn tch yu cu tch hp............................................................................ 33

1.1.10. Phn tch thc tin nghip v tn ti .......................................................... 34

1.1.11.Phn tch yu cu kh nng quy m ............................................................ 34

1.2 Xc nh yu cu .................................................................................................. 35

1.2.1 Yu cu v m t yu cu .............................................................................. 35

1.2.2 Phn loi yu cu ........................................................................................... 37

1.2.3 Cc bc xc nh yu cu ............................................................................ 42

1.2.3.1 Kho st hin trng ..................................................................................... 43

1.2.3.2 Lp danh sch cc yu cu ......................................................................... 44

1.2.4 Kho st mt s phn mm tiu biu ............................................................ 54

Tra cu........................................................................................................................ 57

2. M hnh ha yu cu h thng................................................................................ 58


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2.1 Cc nguyn l m hnh ha .............................................................................. 58

2.3 S phn r chc nng .................................................................................. 59

2.3 M hnh bn mu (protoype) ........................................................................... 59

2.4 S lung d liu........................................................................................... 60

2.5 M hnh hng i tng................................................................................. 602. 6 V d minh ha t yu cu sang m hnh ha ......................................................... 61

Chng 3: THIT K PHN MM ............................................................................. 64

1.Tng quan v thit k .................................................................................................. 64

1.1.K thut thit k ................................................................................................... 65

1.1.1.Thit k trn xung (Top-down) ................................................................... 65

1.1.2.Thit k t di ln (Bottomup).................................................................. 651.1.3.Thit k h thng ........................................................................................... 65

1.1.4.Thit k bn mu (prototype) ........................................................................ 66

1.1.5.Phn r thit k .............................................................................................. 66

1.1.5.1 Phn r hng chc nng ........................................................................... 66

1.1.5.2 Phn r hng d liu................................................................................. 67

1.1.5.3 Phn r hng i tng ............................................................................ 73

1.2. Thit k giao din ngi dng............................................................................. 74

1.3.Ca s hi thoi (dialog window): ....................................................................... 74

1.4 Thit k hng chc nng .................................................................................... 75

1.5.Thit k hng i tng ..................................................................................... 75

2.Kin trc phn mm .................................................................................................... 76

3.Phng php thit k phn mm ................................................................................. 77

4.V d minh ha ............................................................................................................ 77

Chng 4: THIT K D LIU ................................................................................... 84

1.Tng quan .................................................................................................................... 84

2.Kt qu ca thit k ..................................................................................................... 84

3.Qu trnh thit k ......................................................................................................... 86

4.Phng php thit k d liu ....................................................................................... 90

4.1.Phng php trc tip .......................................................................................... 90

4.2.Phng php gin tip .......................................................................................... 92

4.2.1.Lp s lp ................................................................................................. 92


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4.2.2.nh x s lp............................................................................................ 93

4.2.3.nh x quan h .............................................................................................. 93

4.2.4.Hon chnh s logic .................................................................................. 93

5.Thit k d liu vi tnh ng n............................................................................... 95

6.Thit k d liu v yu cu cht lng........................................................................ 956.1.Xem xt tnh tin ha ........................................................................................... 96

6.2.Xem xt tnh hiu qu (tc ) ............................................................................. 97

6.3.Xem xt tnh hiu qu (lu tr) ............................................................................ 98

Chng 5 : THIT K GIAO DIN............................................................................ 102

1.Tng quan .................................................................................................................. 102

1.1.Kt qu thit k................................................................................................... 1021.2.Phn loi mn hnh giao din ............................................................................. 104

1.3.Qu trnh thit k ................................................................................................ 105

2.Thit k mn hnh ...................................................................................................... 112

2.1.M t mn hnh chnh ......................................................................................... 112

2.2.Thit k mn hnh chnh dng thc n (menu) ................................................ 113

3.Thit k mn hnh tra cu .......................................................................................... 114

3.1.M t mn hnh tra cu....................................................................................... 1143.2.Th hin tiu chun tra cu ................................................................................ 114

3.2.1.Tra cu vi biu thc logic ......................................................................... 114

3.2.2.Tra cu vi hnh thc cy............................................................................ 114

3.2.3.Tch hp....................................................................................................... 114

3.3.Th hin kt qu tra cu ..................................................................................... 115

3.3.1.Kt qu tra cu dng thng bo................................................................... 115

3.3.2.Kt qu tra cu dng danh sch n ........................................................... 115

3.3.3.Kt qu tra cu dng xu cc danh sch ..................................................... 115

3.3.4.Cy cc danh sch ....................................................................................... 115

3.4.Thao tc ngi dng v x l ca phn mm .................................................... 115

4.Thit k mn hnh nhp liu ...................................................................................... 116

4.1.M t mn hnh nhp liu ................................................................................... 116

4.2.Cc hnh thc trnh by mn hnh nhp liu....................................................... 117

4.2.1.Thit k mn hnh nhp liu dng danh sch............................................... 117

4.2.2.Thit k mn hnh nhp liu dng h s...................................................... 118


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4.2.3.Thit k mn hnh nhp liu dng phiu...................................................... 118

Chng 6: CI T ................................................................................................... 119

1.Tng quan .................................................................................................................. 119

2.Mi trng lp trnh .................................................................................................. 120

2.1.Cht lng i hi cho mt ngn ng lp trnh: ................................................ 120

2.2.Kh nng M un ha ca ngn ng lp trnh ................................................... 120

2.3.Gi tr su liu ca ngn ng lp trnh ............................................................... 121

2.4.Cu trc d liu trong ngn ng lp trnh .......................................................... 121

2.5.V d minh ha ................................................................................................... 122

3.Phong cch lp trnh .................................................................................................. 122

3.1.Tnh cu trc ....................................................................................................... 123

3.2.Th mnh ca din t........................................................................................ 123

3.3.Cch thc trnh by bn ngoi ............................................................................ 124

4.nh gi cht lng cng vic .................................................................................. 125

4.1.Hin thc tng cng ......................................................................................... 125

4.2.nh gi li thit k v chng trnh (Design and Code Review) ..................... 126

5.V d minh ha .......................................................................................................... 126

Chng 7: KIM TH PHN MM ......................................................................... 129

1.Tng quan .................................................................................................................. 129

2.Yu cu i vi kim th .......................................................................................... 129

3.Cc k thut kim th................................................................................................ 130

3.1.Phng php hp en (Kim th chc nng)..................................................... 130

3.2.Phng php hp trng (Kim th cu trc) ...................................................... 131

4.Cc giai on v chin lc kim th ....................................................................... 1324.1.Kim th n v .................................................................................................. 132

4.2.Kim th tch hp ............................................................................................... 133

4.2.1.Trn xung................................................................................................... 133

4.2.2.Di ln ....................................................................................................... 134

4.3.Kim th chp nhn............................................................................................ 135

4.4.Kim th beta ..................................................................................................... 135

4.5.Kim th h thng .............................................................................................. 1355.V d minh ha .......................................................................................................... 135


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Chng 8: SU LIU .................................................................................................. 137

1.Tng quan .................................................................................................................. 137

2.Su liu ngi dng .................................................................................................. 137

2.1.M t chc nng ................................................................................................. 138

2.2.Bng Gii thiu .................................................................................................. 138

2.3.Bng tham kho .................................................................................................. 138

2.4.Su liu ci t ................................................................................................... 138

3.Su liu h thng ....................................................................................................... 139

4.Cht lng ca su liu ............................................................................................. 140

5.Botr su liu ........................................................................................................... 141

6.Cc mu su liu cho qui trnh lm phn mm ......................................................... 1416.1.Xc nh yu cu (SRS) ..................................................................................... 141

6.2.Thit k ............................................................................................................... 142

6.2.1.M t thit k phn mm (SDD) ................................................................. 142

6.2.2.System Design Rationale Document (SDRD)............................................. 143

Ph Lc A ..................................................................................................................... 144

1.Cu hi l thuyt ....................................................................................................... 144

2.Ni dung v yu cu bi tp ...................................................................................... 1452.1.Qun l thu bao in thoi ................................................................................ 145

2.2.Qun l hc sinh trng ph thng trung hc .................................................... 146

2.3.Qun l cc ti khon trong ngn hng .............................................................. 147

2.4.Theo di k hoch sn lng cao su................................................................... 147

2.5.Qun l gii v ch bng .............................................................................. 148

2.6.Thi trc nghim trn my tnh ............................................................................ 148

2.7.Qun l trung tm gii thiu vic lm sinh vin ................................................ 149

2.8.Phn mm qun l bn sch ............................................................................... 150

2.9.Phn mm qun l bn v chuyn bay ............................................................... 150

2.10. Phn mm qun l phng mch....................................................................... 150

3.Bi tp nng cao ........................................................................................................ 150

3.1. ng k mn hc v hc ph ............................................................................. 150

3.1. Qun l n Nin lun ................................................................................. 152

3.2. Qun l c s sn xut v cht lng sn phm................................................ 153

3.3. Qun l lng sn phm.................................................................................... 154


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3.4. Qun l cng tc thc hnh tin hc ................................................................... 155

3.5. Cng tc t chc thi hc k ............................................................................... 156

4. Biu mu thc hin n mn hc .......................................................................... 157

PHC LC B ............................................................................................................... 1601. Phn mm qun l th vin ...................................................................................... 160

2. Phn mm qun l gii v ch bng ................................................................... 163


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Chng 1: TNG QUAN V CNG NGH PHN MM

1. CC KHI NIM C BN

1.1. Phn mm

1.1.1. Cc khi nim

Chng trnh my tnh l mt trnh t cc ch th hng dn my tnh lm vic nhm

hon thnh mt cng vic no do con ngi yu cu.

Phn mm l mt h thng cc chng trnh c th thc hin trn my tnh nhm h tr

cc nh chuyn mn trong tng lnh vc chuyn ngnh thc hin tt nht cc thao tc nghip

v ca mnh. Nhim v chnh yu ca phn mm l cho php cc nh chuyn mn thc hincc cng vic ca h trn my tnh d dng v nhanh chng hn so vi khi thc hin cng

cng vic trong th gii thc.

Hot ng ca mi phn mm l s m phng li cc hat ng ca th gii thc trong

mt gc thu hp no trn my tnh. Qu trnh s dng mt phn mm chnh l qu trnh

ngi dng thc hin cc cng vic trn my tnh hon tt mt cng vic tng ng

trong th gii thc.

Lp phn mm l h thng cc phn mm trn cng lnh vc hat ng no . Do

cng lnh vc hat ng nn cc phn mm ny thng c cu trc v chc nng (cng vic

m ngi dng thc hin trn my tnh) tng t nhau. Mc tiu ca ngnh K ngh phn

mml hng n khng nhng xy dng c cc phn mm c cht lng m cn cho

php xy dng d dng mt phn mm mi t cc phn mm c sn trong cng knh vc

(thm ch trong cc lnh vc khc).

STT Lp phn mm Cc phn mm

1 H tr gii bi tp lng gic, hnh hc, gii

tch, s hc,

2 Tr chi c car, c tng, c vua,

xp hnh,

3 Xp lch biu thi u, thi kha biu, hi

ngh,

4 Xt tuyn nhn s, hc sinh lp 10

3


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5 Bnh chn Sn phm, cu th,

6 Qun l hc sinh Mm non, trung hc, trung

tm

7 Bn hng thuc ty, vt liu xy

dng, my tnh

8 Qun l thu bao in, in thoi, nc,

9 Cho mn sch, truyn, phim,

Bng 1.1: Cc phn mm v lp phn mm tng ng

1.1.2. Phn loi

Phn mm h thng l nhng phn mm m nhn cng vic tch hp v iu khin cc

thit b phn cng ng thi to ra mi trng thun li cc phn mm khc v ngi s

dng c th thao tc trn nh mt khi thng nht m khng cn phi quan tm n nhng

chi tit k thut phc tp bn di nh cch thc trao i d liu gia b nh chnh v a,

cch hin th vn bn ln mn hnh, ...

Phn mm ng dng l nhng phn mm c dng thc hin mt cng vic xc

nh no . Phn mm ng dng c th ch gm mt chng trnh n gin nh chng

trnh xem nh, hoc mt nhm cc chng trnh cng tng tc vi nhau thc hin mt

cng vc no nh chng trnh x l bn tnh, chng trnh x l vn bn, ...

1.1.3. Kin trc phn mm

Sau khi c cc khi nim c bn nht v phn mm, tip sau y chng ta s i su

vo tm hiu cu trc chi tit cc cu trc chi tit cc thnh phn bn trong phn mm. Phn

mm bao gm 3 thnh phn:

a) Thnh phn giao tip (giao din)

Cho php tip nhn cc yu cu v vic mun thc hin v cung cp cc d liu ngun

lin quan n cng vic hoc t cc thit b thu thp d liu (cn, o nhit , t

bo quang hc, )

Cho php trnh by cc kt qu ca vic thc hin cc yu cu cho ngi dng (kt qu

ca cng vic khi thc hin trn my tnh) hoc iu khin hat ng cc thit b iu khin

(ng m ca, bt m my)

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Mt cch tng qut thnh phn giao tip l h thng cc hm chuyn v vic nhp/xut

d liu (hm nhp/xut) cng vi hnh thc trnh by v t chc lu tr d liu tng ng,

mc tiu chnh ca cc hm ny l a d liu t th gii bn ngoi phn mm vo bn trong

hoc ngc li.

Trong phm vi gio trnh ny ch gii hn xt n giao tip vi ngi s dng phn

mm v khi c tn gi c th hn l thnh phn giao din.

b) Thnh phn d liu

Cho php lu tr li (hm ghi) cc kt qu x l (vic mn sch c kim tra

hp l, bng lng thng c tnh) trn b nh ph vi t chc lu tr c xc nh

trc (tp tin c cu trc, tp tin nh phn, c s d liu).

Cho php truy xut li (hm c) cc d liu lu tr phc v cho cc hm x l

tng ng.

Mt cch tng qut thnh phn d liu l h thng cc hm chuyn v c ghi d liu

(hm c/ghi) cng vi m hnh t chc d liu tng ng. Mc tiu chnh ca cc hm ny

l chuyn i d liu gia b nh chnh v b nh ph.

c) Thnh phn x l

Kim tra tnh hp l ca cc d liu ngun c cung cp t ngi dng theo cc quy

trnh rng buc trong th gii thc (ch cho mn ti a 3 quyn sch, mi lp hc c ti a

50 hc sinh, )

Tin hnh x l cho ra kt qu mong i theo quy nh tnh ton c sn trong th gii

thc (quy tc tnh tin pht khi tr sch tr, quy tc tnh tin in, quy tc tr gp khi mua

nh) hoc theo thut gii t xut (xp thi kha biu t ng, nn nh)

Vic x l da trn d liu ngun t ngi s dng cung cp (tnh nghimphng trnh bc 2 da trn cc h s nhp) hoc d liu lu tr c sn (tnh tn kho

thng da trn cc phiu nhp xut lu tr) hoc c hai (tnh tin pht da trn ngy tr

sch c nhp vo v thng tin v loi sch c lu tr) ty vo x l c th. Tng

t, vic x

l cho ra kt qu c th dng xut cho ngi dng xem qua thnh phn giao din (trnh

by nghim, xut tin pht), hay cng c th lu tr li qua thnh phn d lu (s sch hin

ang c mn ca mt c gi) hoc c hai (bng lng, bng tn kho)Mt cch tng qut, thnh phn x l l h thng cc hm chuyn v x l tnh ton,

bin i d liu. Cc hm ny s dng d liu ngun t cc hm trong thnh phn giao din

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(hm nhp) hay thnh phn d liu (hm c d liu) kim tra tnh hp l (hm kim tra) v

sau tin hnh x l (hm x l) nu cn thit cho ra kt qu m s c trnh by cho

ngi dng xem qua cc hm trong thnh phn giao din (hm xut) hoc lu tr li qua cc

hm trong thnh phn d liu (hm ghi).

STT Thnh phn Hm ngha Ghi ch

1 Thnh phn

giao din

Hm nhp

Hm xut

Nhp yu cu,

d liu ngun.

Xut kt qu

x l

Cn xc

nh hnh

thc

nhp/xut

v t chc

d liu

tng ng

2 Thnh phn

x l

Hm kim

tra

Hm x

l

Kim tra tnh

hp l ca d

liu.

X l tnh

ton, pht

sinh, bin i

trn d liu

S dng

hm nhp,

hm c.

S dng

hm nhp,

hm c,

hm xut,

hm ghi

3 Thnh phn

d liu

Hm c

Hm ghi

c d liu t

b nh ph

vo b nh

chnh.

Ghi d liu t

b nh chnh

vo b nh

ph

Cn xc

nh cchh

thc t

chc lu

tr d liu

Bng 1.2: Danh sch cc hm cng ngha tng ng

1.2. Cht lng phn mm

1.2.1. Tnh ng n

Tnh ng n ca phn mm c th hin ch sn phm thc hin y vchnh xc cc yu cu ca ngi dng. Tnh ng n y cn phi hiu theo ngha rng l

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chng trnh cn phi thc hin c trong c nhng trng hp m d liu u vo l

khng hp l.

V d, nu mt trong s cc chc nng ca phn mm l sp xp mt tp tin cs

lng mu tin ty theo mt ct ty theo chiu tng hoc gim th nhng trng hp sau

l vi phm tnh ng n ca chng trnh:

Khng th thc hin c (treo my) khi tp tin rng (khng c mu tin no).

Khng th thc hin hoc thc hin nhng cho kt qu sai khi cc mu tin c hn

100 ct hoc c qu nhiu mu tin.

Khng th thc hin hoc cho kt qu sai khi cc ct c chiu di ln hn 125

bytes.

Khng th sp xp theo chiu tng dn.

Tnh ng n ca mt sn phm phn mm c xc minh qua cc cn c sau y:

Tnh ng n ca thut ton.

Tnh tng ng ca chng trnh vi thut ton. Thut ton c th ng nhng

chng trnh lp ra khng tng ng vi thut ton nn khi thc hin s cho kt

qu sai.

Tnh ng n ca chng trnh c th c chng minh trc tip trong vn bn ca

chng trnh.

Tnh ng n cng c th c khng nh dn qua vic kim th, vic p dng

chng trnh trong mt khong thi gian di trn din rng v vi tn sut s

dng cao.

1.2.2. Tnh tin ha

Cho php ngi dng c th khai bo cc thay i v qui nh vi phn mm ty theo

cc thay i trong th gii thc lin quan (thay qui nh v s sch mn ti a, cng thc

tnh tin pht, cng thc tnh tin in)

Sn phm c th m rng, tng cng v mt chc nng mt cch d dng.

1.2.3. Tnh hiu qu

Tnh hiu qu ca mt sn phm phn mm c xc nh qua cc tiu chun sau:

Hiu qu kinh t hoc ngha, gi tr thu c do p dng sn phm . Tc x l ca phn mm (v) tnh bng t l gia khi lng i tng cn phi x

l (m) v tng thi gian (t) cn thit x l cc i tng .

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S dng ti u ti nguyn ca my tnh (CPU, b nh)

1.2.4. Tnh tin dng

Sn phm phi tnh n nhng yu t tm l sau y ca ngi dng:

D hc, c giao din trc quan t nhin.

D thao tc,

1.2.5. Tnh tng thch

Trao i d liu vi cc phn mm khc c lin quan (nhn danh mc sch t tp tin

Excel, gi bo co tng kt nm hc n phn mm WinFax, )

Giao tip ni b

Giao tip bn ngoi

1.2.6. Tnh ti s dng

Sn phm phn mm c th p dng cho nhiu lnh vc theo nhiu ch lm vic

khc nhau.

Cc phn mm cng lp

Cc phn mm khc lp

1.3. Cng ngh phn mm

1.3.1. S ra i

Vo nhng nm 1950 khi my tnh ra i chnh thc (khng ch c dng trong cc

phng th nghim m bt u ng dng trong hat ng x hi) cc phn mm u tin cng

c ra i vi s lng cn rt t i v ch yu phc v cho lnh vc tnh ton (c bit

trong quc phng).

n nhng nm 1960, tri qua 10 nm pht trin s lng cc phn mm tng ln rt

nhiu v c ng dng rng ri trong nhiu lnh vc. Vo thi im ny pht sinh mt vn

m cc chuyn gia gi l cuc khng hong phn mm. Cuc khng hong phn mm th

hin 2 yu t chnh:

- S lng cc phn mm tng vt (do s pht trin ca phn cng: tng kh nng,

gi thnh h)

- C qu nhiu khuyt im trong cc phn mm c dng trong x hi

o Thc hin khng ng yu cu (tnh ton sai, khng n nh)

o Thi gian bo tr, nng cp qu lu, tn chi ph cao, hiu qu thp.

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o Kh s dng

o Thc hin chm

o Kh chuyn i d liu gia cc phn mm

o ..

gii quyt vn trn mt hi ngh c triu tp bn v cch gii quyt. Hi

ngh tin hnh xem xt, phn tch v xc nh nguyn nhn gy ra cuc khng hong phn

mm. Kt lun nh sau:

- Vic tng vt ca s lng phn mm l iu hp l v iu ny s cn tip din.

- Cc khuyt im ca phn mm c ngun gc chnh t phng php, cch thc tin hnh xy

dng phn mm:

o Cm tnh: mi ngi theo mt phng php ring.o Th s, n gin: ch tp trung vo vic lp trnh m t quan tm n cc cng

vic cn lm khc trc khi lp trnh (kho st hin trng, phn tch yu cu, thit

k).

o Th cng: cng c h tr chnh khi xy dng phn mm ch l trnh bin dch.

Vi cc kt lun nh trn, hi ngh xut khai sinh mt ngnh khoa hc mi: K

ngh phn mmvi nhim v chnh l nghin cu v cc phng php tin hnh xy dng

phn mm.

1.3.2. nh ngha

K ngh phn mml mt lnh vc nghin cu ca tin hc nhm xut cc nguyn

l, phng php, cng c, cch tip cn phc v cho vic thit k, ci t cc sn phm phn

mm t c y cc yu cu v cht lng phn mm.

Do qu trnh tin ha ca ngnh K ngh phn mmnn khi nim v n cng thay

i theo thi gian. Hn na do y l mt lnh vc mi nn cc khi nim vn cn ph thucrt nhiu vo quan im ch quan ca tng ngi khc nhau. C th nh sau:

- Bauer[1969]: vic thit lp v s dng cc nguyn l cng ngh ng n thu

c phn mm mt cch kinh t va tin cy va lm vic hiu qu trn cc my

thc.

- Ghezzi[1991]: l mt lnh vc ca khoa hc my tnh lin quan n vic xy dng cc

phn mm va ln va phc tp bi mt hay mt s nhm k s.

- IEEE[1993]:

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1. Vic p dng phng php tip cn c h thng, bi bn v c

lng ha trong pht trin, vn hnh v bo tr phn mm.

2. Nghin cu cc phng php tip cn c dng trong (1).

- Sommervile[1995]: l lnh vc lin quan n l thuyt, phng php v cng cdng cho pht trin phn mm.

- Kawamura[1995]: l lnh vc hc vn v cc k thut, phng php lun cng ngh

hc (l lun v k thut c hin thc ha trn cc nguyn l, nguyn tc

xc nh) trong ton b quy trnh pht trin phn mm nhm nng cao c cht v

lng ca sn xut phn mm.

- Pressman[1995]: l b mn tch hp c qui trnh, cc phng php, cc cng c

pht trin phn mm my tnh.

C th nh ngha tm tt v K ngh phn mmnh sau: K ngh phn mml mt

nghnh khoa hc nghin cu v vic xy dng cc phn mm c cht lng trong

khong thi gian v chi ph hp l.

Mc tiu nghin cu c chia thnh 2 phn r nt:

1. Xy dng phn mm c cht lng.

2. Xy dng phn mm trong thi gian v chi ph hp l.

1.3.3. i tng nghin cu

Hng n vic xy dng cc phn mm c cht lng nh nu, ngnh cng ngh

phn mm a ra 3 i tng nghin cu chnh: Qui trnh cng ngh, Phng php

pht trin, Cng c v mi trng pht trin phn mm.

- Qui trnh cng ngh phn mm: H thng cc giai on m qu trnh pht trin phn mm

phi tri qua. Vi mi giai on cn xc nh r mc tiu, kt qu nhn t giai on trc cng chnh l kt qu chuyn giao cho giai on kt tip.

- Phng php pht trin phn mm: H thng cc hng dn cho php tng bc thc

hin mt giai on no trong qui trnh cng ngh phn mm.

- Cng c v mi trng pht trin phn mm: H thng cc phn mm tr gip chnh

trong lnh vc xy dng phn mm. Cc phn mm ny s h tr cc chuyn vin tin hc

trong cc bc xy dng phn mm theo mt phng php no vi mt qui

trnh c chn trc.

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2. QUI TRNH CNG NGH PHN MM

Nh ni xy dng c phn mm c cht lng qu trnh pht trin phi tri qua

rt nhiu giai on. Mi giai on c mc tiu v kt qu chuyn giao xc nh. Trnh t thc

hin cc giai on ny chnh l chu k sng ca mt phn mm.

Ni cch khc, chu k sng ca mt phn mm l khong thi gian m trong mt sn

phm phn mm c pht trin, s dng v m rng cho n khi sn phm phn mm

khng cn c s dng na.

Chu k sng ca phn mm c phn chia c phn chia thnh cc pha chnh nh:

xc nh, pht trin, kim th, bo tr (vn hnh). Phm vi v th t cc pha khc nhau ty

theo tng m hnh c th.

2.1. Cc bc c bn trong xy dng phn mm

2.1.1. Xc nh

y l bc hnh thnh bi ton hoc ti. bc ny thit k trng hoc phn tch

vin h thng phi bit c vai tr ca phn mm cn pht trin trong h thng, ng thi

phi c lng cng vic, lp lch biu v phn cng cng vic.

Bn cnh chng ta phi bit ngi t hng mun g. Cc yu cu cn phi c thu

thp y v c phn tch theo chiu ngang (rng) v chiu dc (su). Cng c s dng

ch yu giai on ny l cc lc , s phn nh r cc thnh phn ca h thng v

mi lin quan gia chng vi nhau.

2.1.2. Pht trin

Da vo cc ni dung xc nh c, nhm pht trin phn mm dng ngn ng c

t hnh thc (da trn cc kin trc ton hc) hoc phi hnh thc (ta ngn ng t nhin) hoc kt

hp c hai m t nhng yu t sau y ca chng trnh: Gi tr nhp, gi tr xut.

Cc php bin i

Cc yu cu cn t c mi im ca chng trnh.

Phn c t ch quan tm ch yu n gi tr vo, ra ch khng quan tm n cu trc

v ni dung cc thao tc cn thc hin.

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Sau bc thit k l bc trin khai cc c t chng trnh thnh mt sn phm phn

mm da trn mt ngn ng lp trnh c th. Trong giai on ny cc lp trnh vin s tin

hnh ci t cc thao tc cn thit thc hin ng cc yu cu c c t.

Cng vic cui cng ca giai on pht trin l chng ta cn phi chng minh

tnh ng n ca chng trnh sau khi tin hnh ci t. Tuy nhin thng thng bc

ny chng ta coi cc chng trnh nh nhng hp en. Vn t ra l xy dng mt cch c

ch ch cc tp d liu nhp khc nhau giao cho chng trnh thc hin ri da vo kt

qu thu c nh gi chng trnh. Cng vic nh trn c gi l kim th chng trnh.

Cng vic kim th nhm vo cc mc tiu sau:

Kim tra pht hin li ca chng trnh. Lu rng kim th khng m bo

tuyt i tnh ng n ca chng trnh do bn cht quy np khng hon tonca cch lm.

Kim tra tnh n nh, hiu qu cng nh kh nng ti a ca chng trnh.

Ty theo mc ch m ngi ta thit k cc tp d liu th sao cho c th ph ht cc

trng hp cn quan tm.

2.1.3. Bo tr (Vn hnh)

Cng vic qun l vic trin khai v s dng phn mm cng l mt vn cn cquan tm trong qui trnh pht trin phn mm. Trong qu trnh xy dng phn mm, ton b

cc kt qu phn tch, thit k, ci t v h s lin quan cn phi c lu tr v qun l cn

thn nhm m bo cho cng vic c tin hnh mt cch hiu qu nht v phc v cho

cng vic bo tr phn mm v sau.

Nh vy cng vic qun l khng ch dng li trong qu trnh xy dng phn mm m tri

li cn phi c tin hnh lin tc trong sut qu trnh sng ca n.

2.2. Mt s m hnh trin khai xy dng phn mm

C nhiu m hnh cn khc nhau trin khai cc bc c bn trong qu trnh pht

trin phn mm. Mi m hnh s chia vng i ca phn mm theo mt cch khc nhau

nhm m bo qui trnh pht trin phn mm s dn n thnh cng. Trong phn tip theo

ca gio trnh chng ta s tm hiu qua cc m hnh pht trin phn mm tiu biu nht ang

c p dng.

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2.2.1. M hnh thc nc:

M hnh thc nc l mt trong nhng m hnh u tin v ph bin c p

dng trong qu trnh pht trin phn mm. M hnh ny chia qu trnh pht trin phn mm

thnh nhng giai on tun t ni tip nhau. Mi giai on s c mt mc ch nht nh.

Kt qu cu giai on trc s l thng tin u vo cho giai on tip theo sau. Ty theo qui

m ca phn mm cn pht trin m m hnh thc nc s c nhng bin th khc nhau nh

sau:

Qui trnh 2 giai on: L qui trnh n gin nht. Theo qui trnh ny vic pht trin

phn mm ch tri qua 2 giai on:

o Xc nh yu cu: c tin hnh ngay khi c nhu cu v vic xy dng phn

mm.

- Mc tiu: Xc nh chnh xc cc yu cu t ra cho phn mm s xy dng.

- Kt qu nhn: Thng tin v hot ng ca th gii thc.

- Kt qu chuyn giao: Danh sch cc yu cu (cng vic s thc hin trn my

tnh) cng vi cc thng tin miu t chi tit v cc yu cu (cch thc thc

hin trong th gii thc).

o Lp trnh (ci t): c tin hnh ngay sau khi kt thc vic xc nh yu cu.

- Mc tiu: To lp phn mm mong mun theo yu cu.

- Kt qu nhn: Danh sch cc yu cu cng cc thng tin c lin quan.

- Kt qu chuyn giao: Chng trnh ngun ca phn mm vi cu trc c s

d liu tng ng (nu cn thit) v chng trnh thc hin c trn

my tnh (chng trnh ngun c bin dch)

Qui trnh 3 giai on: L qui trnh ci tin ca qui trnh 2 giai on bng cch b sung

thm mt giai on trung gian mi gia xc nh yu cu v lp trnh (c sa i)

o Xc nh yu cu: c tin hnh ngay khi c nhu cu v vic xy dng

phn mm.





hin trong th gii thc)

o Thit k: c tin hnh ngay sau khi kt thc vic xc nh yu cu.

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- Mc tiu: M t cc thnh phn ca phn mm (m hnh ca phn mm) trc khi

tin hnh ci t.

- Kt qu nhn: Danh sch cc yu cu v thng tin lin quan.

- Kt qu chuyn giao:

M t thnh phn giao din: cc hm nhp/xut, cu trc d liu

nhp/xut.

M t thnh phn x l: cc hm kim tra x l.

M t thnh phn d liu: cc hm c/ ghi, t chc lu tr trn b

nh ph.

o Lp trnh (ci t): c tin hnh ngay sau khi kt thc vic thit k.

- Mc tiu: To lp phn mm theo yu cu.

- Kt qu nhn: M hnh phn mm




Qui trnh 4 giai on: L qui trnh ci tin ca qui trnh pha trc bng cch b sung

thm mt giai on mi gia xc nh yu cu v thit k (c sa i)


mm.






o

Phn tch: c tin hnh ngay sau khi kt thc vic xc nh yu cu.- Mc tiu: M t li th gii thc thng qua cc m hnh (m hnh th

gii thc) trc khi thit k.


- Kt qu chuyn giao:

M hnh x l (h thng cc cng vic trong th gii thc cng vi

quan h gia chng)

M hnh d liu (h thng cc loi thng tin c s dng trong th

gii thc cng vi quan h gia chng)

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Cc m hnh khc (khng gian, thi gian, con ngi) nu cn thit.

o Thit k: c tin hnh ngay sau khi kt thc vic phn tch.


tin hnh ci t.- Kt qu nhn: M hnh th gii thc.

- Kt qu chuyn giao:


nhp/xut.


M t thnh phn d liu: cc hm c/ghi, t chc lu tr trn b nh

ph.


- Mc tiu: To lp phn mm theo yu cu

- Kt qu nhn: M hnh phn mm




Qui trnh 5 giai on: L qui trnh ci tin ca qui trnh pha trc bng cch b

sung thm mt giai on mi sau giai on lp trnh nhm tng cng tin cy ca

phn mm.


mm.


- Kt qu nhn: Thng tin v hot ng ca th gii thc.- Kt qu chuyn giao: Danh sch cc yu cu (cng vic s thc hin trn my



o Phn tch: c tin hnh ngay sau khi kt thc vic xc nh yu cu.

- Mc tiu: M t li th gii thc thng qua cc m hnh (m hnh th

gii thc) trc khi thit k.


- Kt qu chuyn giao:

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M hnh x l (h thng cc cng vic trong th gii thc cng vi

quan h gia chng)

M hnh d liu (h thng cc loi thng tin c s dng trong th

gii thc cng vi quan h gia chng)

Cc m hnh khc (khng gian, thi gian, con ngi) nu cn thit.

o Thit k: c tin hnh ngay sau khi kt thc vic phn tch.


tin hnh ci t.

- Kt qu nhn: M hnh th gii thc.

- Kt qu chuyn giao:


nhp/xut.


M t thnh phn d liu: cc hm c/ ghi, t chc lu tr trn b

nh ph.


- Mc tiu: To lp phn mm theo yu cu.

- Kt qu nhn: M hnh phn mm.- Kt qu chuyn giao: Chng trnh ngun ca phn mm vi cu trc c s


my tnh (chng trnh ngun c bin dch).

o Kim th: c tin hnh ngay sau khi c kt qu (tng phn) ca vic lp

trnh.

- Mc tiu: Tng tin cy ca phn mm.

- Kt qu nhn: Danh sch yu cu.

M hnh phn mm.

Phn mm.

- Kt qu chuyn giao: Phn mm vi tin cy cao ( tm v sa li).

o Bo tr: Cng vic ca giai on bao gm vic ci t v vn hnh phn mm

trong thc t.

- Mc tiu: m bo phn mm vn hnh tt

- Kt qu nhn: phn mm hon thng

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- Kt qu chuyn giao: cc phn nh ca khch hng trong qu trnh s dng

phn mm.

Nhn xt:

M hnh thc nc gip chng ta c th d dng phn chia qu trnh xy dng phnmm thnh nhng giai on hon ton c lp nhau. Tuy nhin, cc d n ln him khi tun

theo dng chy tun t ca m hnh v thng phi lp li cc bc nng cao cht lng.

Hn na, khch hng him khi tuyn b ht cc yu cu trong giai on phn tch.

M hnh ny cng c mt hn ch l chng ta rt kh thc hin cc thay i mt khi

thc hin xong mt gii on no . iu ny lm cho vic xy dng phn mm rt kh

thay i cc yu cu theo mun ca khch hng. Do , phng php ny ch thch hp cho

nhng trng hp m chng ta hiu rt r cc yu cu ca khch hng.

Ch : M hnh thc nc c th c ci tin bng cch cho php quay lui khi pht

hin li trong giai on pha trc.

2.2.2. M hnh bn mu phn mm

Tng t nh m hnh thc nc vi b sung vo cc giai on thc hin phn mm

mu ngay khi xc nh yu cu nhm mc tiu pht hin nhanh cc sai st v yu cu. Cc

giai on trong m hnh bn mu phn mm c th tin hnh lp i lp li ch khng nht

thit phi theo trnh t nht nh.

Ngay sau khi giai on xc nh yu cu, nh pht trin phn mm a ra ngay mt bn

thit k s b v tin hnh ci t bn mu u tin v chuyn cho ngi s dng. Bn mu

ny ch nhm miu t cch thc phn mm hot ng cng nh cch ngi s dng tng

tc vi h thng.

Ngi s dng sau khi xem xt s phn hi thng tin cn thit li cho nh pht trin.

Nu ngi s dng ng vi bn mu a th ngi pht trin s tin hnh ci t thc

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s. Ngc li c hai phi quay li giai on xc nh yu cu. Cng vic ny c lp li lin tc

cho n khi ngi s dng ng vi cc bn mu do nh pht trin a ra.

Nh vy y l mt hng tip cn tt khi cc yu cu cha r rng v kh nh gi

c tnh hiu qu ca cc thut ton. Tuy nhin, m hnh ny cng c nhc im l tnh

cu trc khng cao do khch hng d mt tin tng.

2.2.3. M hnh xon c

M hnh ny chnh l s kt hp ca m hnh bn mu thit k v m hnh thc ncc lp li nhiu ln. ln lp tip theo h thng s c tm hiu v xy dng hon thin

hn ln lp trc .

mi ln lp cc yu cu ca ngi s dng s c hiu ngy cng r rng hn v

cc bn mu phn mm cng ngy mt hon thin hn. Ngoi ra cui mi ln lp s c

thm cng on phn tch mc ri ro quyt nh xem c nn i tip theo hng ny na

hay khng.

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M hnh ny ph hpvi cc h thng phn mm ln do c kh nng kim sot ri ro tng bc tin ha. Tuy nhin vn cha c s dng rng ri nh m hnh thc nc hoc bn

mu do i hi nng lc qun l, nng lc phn tch ri ro cao.

3. CC PHNG PHP XY DNG PHN MM

3.1. Tng quan

3.1.1. Khi nim

tin hnh xy dng mt phn mm, chng ta c th p dng nhiu phng php

khc nhau. Mi phng php c nhng u v khuyt im ring v ph hp vi tng loi

phn mm c th.

Mi phng php s c nhng hng dn c th cc cng vic cn phi thc hin trong

tng giai on trong quy trnh xy dng phn mm.

Bn cnh mi phng php cng s quy nh nhng cch thc khc nhau trnh

by cc kt qu thu c trong qu trnh xy dng phn mm. Nhng quy nh ny c tnhcht nh l ngn ng thng nht cc thnh vin tham gia xy dng phn mm c th trao

i thng tin trong vic xy dng phn mm.

3.1.2. Phn loi

Cc phng php xy dng phn mm c chia lm 02 nhm khc nhau da vo tnh

cht ca cng vic cn thc hin.

Phng php xy dng: Phng php hng chc nng

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Phng php hng d liu

Phng php hng i tng

Phng php t chc qun l

Xy dng phng n

T chc nhn s

c lng ri ro, chi ph

Lp v theo di k hoch trin khai.

Trong phn tip theo ca gio trnh ny, chng ta ch quan tm n cc phng php xy

dng. V phng php t chc qun l chng ta c th tham kho trong gio trnh Qun

l d n xy dng cc h thng thng tin.

3.2. Cc phng php xy dng phn mm

3.2.1. Cch tip cn

a) T trn xung

y l cch gii quyt vn theo hng phn tch. Khi tin hnh xy dng phn mm

theo cch ny, chng ta bt u vi nhng thnh phn chnh ca h thng. Sau , cc thnhphn ny s c phn tch thnh cc thnh phn chi tit v c th hn. Qu trnh phn tch

ny s kt thc khi cc kt qu thu c c mc phc p ng vi mun ca nh xy

dng phn mm.

b) T di ln

Ngc li vi phng php t trn xung, phng php t di ln l cch gii quyt

vn theo hng tng hp. Vi phng php ny, chng ta tin hnh xy dng nhng thnh

phn chi tit, c th m m chng ta d tnh l s c trong h thng. Sau , cc nh pht

trin phn mm s tin hnh kt hp cc thnh phn chi tit ny li vi nhau to nn cc

thnh phn chnh m h thng cn phi c.

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3.2.2. Cch tin hnh

a) Phng php hng chc nng

Vi phng php ny cng vic xy dng phn mm c thc hin da trn cc chc

nng m h thng cn thc hin. Hay ni cch khc chng ta ch trng n thnh phn x l

ca h thng:

Cc thao tc tnh ton

Cc thao tc pht sinh

Cc thao tc bin i.

Phng php chung gii quyt vn l p dng nguyn l chia tr. Khi tin

hnh xy dng phn mm theo phng php ny, chng ta s chia cc cng vic ln m hthng cn thc hin hnh cc cng vic nh hn c lp nhau. Vic phn chia cc cng vic

c tin hnh cho n khi cc cng vic thu c nh chng ta c th tin hnh xy

dng hon chnh. Hnh di: Minh ha cch tip cn theo hng chc nng.

Phng php hng chc nng ch trng n cch gii quyt vn nhng khng

c kh nng che du cc thng tin trng thi ca h thng. iu ny dn n vic cc chcnng trong h thng khng tng thch vi nhau trong vic thc hin thay i cc thng tin

trong h thng. Chnh v vy m cch tip cn ny ch thch hp khi trong h thng c rt t

thng tin cn phi qun l v chia s gia cc chc nng vi nhau. m hnh ha cch x

l thng tin trong h thng dng lc dng d liu (Data Flow Diagrams).

DFD l mt cng c n gin v hu ch miu t cch thc hot ng ca h thng.

DFD s dng cc k hiu sau m t h thng:

vung c gc trn c dng biu din cc chc nng ca h thng.

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vung dng biu din thnh phn d liu trong h thng.

Hnh trn dng biu din cc thnh phn bn ngoi c giao tip vi h thng.

Du mi tn dng biu din hng di chuyn ca d liu.

Cc t kha and v or dng lin kt cc dng d liu khi cn thit.

b) Phng php hng d liu

Ngc li vi phng php hng chc nng, phng php hng d liu ch trng

nhiu n thnh phn d liu cn phi x l trong h thng:

T chc d liu

Khi lng lu tr

Tc truy xut

Khi tin hnh thit k theo phng php hng d liu chng ta bt u vi vic thit

k cc cu trc d liu cn thit c trong bi ton, sau mi tin hnh thit kt cc thao tc vn hnh trn cc cu trc d liu thit k.

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Phng php ny c bit ch thch hp trong cc loi phn mm ch c chc nng

chnh l lu tr v thao tc trn cc loi d liu. Hn ch ca n l khng quan tm n cc

chc nng m h thng cn phi p ng. iu ny dn n vic c kh nng h thng sau khi

thit k khng c y cc chc nng cn thit.

Kt qu thu c sau khi thit k theo phng php hng d liu l m hnh thc th

kt hp (Entity Relationship Diagram). Mt m hnh thc th kt hp in hnh gm c 2

thnh phn c bn: cc thc th v cc mi kt hp.

Mt thc th l mt i tng trong th gii thc m h thng c quan h, hoc

tng tc qua li. Cc thc th c biu din trong s bng cc hnh vung

cng vi tn v c th c thm cc thuc tnh ca thc th.

Mi kt hp biu din s kt hp gia hai hay nhiu thc th. Mi mi kt hp

gm c ba thnh phn c bn:

Mi kt hp gia cc thc th c biu din bng mt ng thng ni

gia hai thc th.

Tn ca mi lin h dng miu t ngha ca mi lin h.

Bn s hai u ca mi kt hp dng xc nh con s ti a v ti

thiu cc thc th lin quan n mi kt hp.

c) Phng php hng i tng

Phng php thit k hng i tng l s kt hp ca phng php hng d liu v

phng php hng chc nng. Phng php ny ch trng n c thnh phn d liu v

chc nng ca h thng.

Theo phng php hng i tng th mt h thng phn mm l mt tp hp cc i

tng c kh nng tng tc vi nhau. Cc i tng chnh l cc s vt v hin tng vt l

cng nh tru tng m chng ta c trong th gii thc. Mi i tng c d liu ring c

che du vi th gii bn ngoi v cc thao tc m i tng c th thc hin trn cc thnh

phn d liu ca i tng.

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Cc i tng lin lc, trao i thng tin vi nhau bng cch gi cc thng ip cho

nhau. Cc thng ip m mi i tng c th x l c gi l giao din ca i tng. Khi

mi thao tc lin quan n cc i tng c phi thc hin thng qua giao din ca i

tng. iu ny gip chng ta m bo rng cc thng tin bn trong cc i tng c bo

v mt cch chc chn.

Chng ta c th s dng nhiu h thng k hiu khc nhau m t cc i tng ca

h thng cng nh mi lin h gia chng. Mt trong s cc h thng k hiu ph bin hin nay

l h thnng k hiu UML.

4. CNG C V MI TRNG PHT TRIN PHN MM

4.1. M u

4.1.1. Khi nim

Cc cng c v mi trng pht trin phn mm l cc phn mm h tr chnh ngi

pht trin trong qu trnh xy dng phn mm. Cc phn mm ny c tn gi chung l CASE

(Computer Aided Software Engineering) tools.

Trong qu trnh pht trin phn mm theo cc quy trnh trn, cc CASE tools c th h

tr c th cho mt giai on no hay cng c th h tr mt s giai on, trong trng hp

ny tn gi chung thng l mi trng pht trin phn mm-SDE (Software Development

Environment).

Vic h tr ca cc CASE tools trong mt giai on bao gm 2 hnh thc chnh:

- Cho php lu tr, cp nht trn kt qu chuyn giao vi mt phng php no .

- Cho php pht sinh ra kt qu chuyn giao cho giao on k tip.

4.2. Phn mm h tr thc hin cc giai on

4.2.1. Phn mm h tr phn tch

- Cng vic h tr chnh

o Son tho cc m hnh th gii thc

o nh x vo m hnh logic

- Cc phn mm: WinA&D, Analyst Pro,

4.2.2. Phn mm h tr thit k

- Cng vic h tr chnh

o Son tho cc m hnh logic

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o nh x vo m hnh vt l

- Cc phn mm: QuickUML, Power Designer, Oracle Designer

4.2.3. Phn mm h tr lp trnh

- Cng vic h tr chnh

o Qun l cc phin bn (D liu, chng trnh ngun, giao din)

o Bin dch

- Cc phn mm: Visual Studio, Visual Basic, Visual C++

4.2.4. Phn mm h tr kim chng

- Cng vic h tr chnh

o Pht sinh t ng cc b d liu th nghim

o Pht hin li- Cc phn mm: WinRuner

4.3. Phn mm h tr t chc, qun l vic trin khai

4.3.1. Xy dng phng n

- Cng vic h tr chnh

o To lp phng n

o D on ri ro

o Tnh chi ph

- Cc phn mm: MS Project, Visio

4.3.2. Lp k hoch

- Cng vic h tr chnh

o Xc nh cc cng vic

o Phn cng

o Lp lch biu

o Theo di thc hin

- Cc phn mm: MS Project, Visio

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Chng 2: PHN TCH V C T YU CU

1. Tng quan

Phn tch yu cu l khu k thut u tin gm nhiu bc nh: nghin cu kh thi,

phn tch m hnh ha, c t thm nh yu cu. Gia on ny c tin hnh phi hp gia

bn pht trin v khch hng v n c vai tr c bit quan trng trong tin trnh pht trin

phn mm.

y l bc hnh thnh bi ton hoc ti. bc ny trng nhm thit k v ngi

phn tch h thng phi bit c ngi t hng mun g. Cc yu cu phi c thu thp

y v c phn tch theo chiu ngang (rng) v dc (su). Cng c s dng ch yu

giai on ny l cc lc , s phn nh r cc i tng ca h thng: lu

(Flowchart), s dng d liu (Data Flow diagram DFD), mng thc th-quan h (Entity-

Relationship Network), s cu trc phn cp (Structural hierarchical schemes), mng ng

ngha (Semantic Network)

1.1 Qu trnh phn tch

1.1.1 Phn tch phm vi d n

Ngi phn tch h thng dng thut ng phm vi ch trch nhim d n phi thc thi.

Ngc li, phm vi d n l nhim v ln v phc tp c thc hin bi chng trnh.

xc nh phm vi d n, bng xc nh qu trnh nghip v ng dng s i u.

l nhng phm vi vn ca ng dng. Ni chung, c hai phn i vi bt k gii

php nghip v: phn trin khai ng dng v phn thc hin bi con ngi hay chng trnh.

nh

ra ranh gii ng dng tc l xc nh qui trnh trch nhim.

Mt khi nh ngha trch nhim ca d n:

Chia trch nhim thnh nhng nhim v con a ra tng cho chnh mnh v bao

nhiu m un chng trnh khc nhau yu cu?

Xc nh bao nhiu vng a l lin quan (chi nhnh vn phng).

c lng s ngi dng ng dng v thi gian ng dng c duy tr.

Tnh chnh xc.

Cui cng, hiu khch hng mong i d n c trin khai.

Ti thi im ny, chng ta c tng phm vi d n. Cn nhc ln d n i vi thi

gian v rng buc ngn sch. Nu d n qu ln v thi gian v tin bc cho chi tr th

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bn bc vn vi khch hng a ra quyt nh thng lng cho tha ng. Chng ta

phi chn la hoc nhiu thi gian hn, hoc nhiu tin hn hoc c hai. Hoc chng ta phi

gim phm vi d n xung. Phn tch tt c nhng tnh hung giai on u ca d n s

lm cho d n thnh cng nhiu hn.

1.1.2 Phn tch m rng yu cu nghip v

a. Xc nh yu cu nghip v

Mi d n s c mt hay nhiu yu cu nghip v. Mi yu cu nghip v l mt m t

tc nhim c th trong nghip v ca khch hng. V d. lu vt qu trnh u t. Mt tc v

nh kim sot u t cn chia nh thnh nhng phn chc chn cho n khi mi phn

m t cng vic chnh xc

phn.

Khi mc ca thnh phn chia nh di mc ti thiu, xc nh li trnh t thnh

Mi tc v c gi l yu cu nghip v hay quy tc nghip v. Quy tc doanh nghip

c vit theo ngn ng c hiu bi nhng ngi khng chuyn my tnh sao cho ngi

dng c th kim tra lut mt cch chnh xc

b. Xc nh yu cu cht lng khch hng

Mi d n phn mm c th yu cu nhanh, bo mt, ph thuc, d dng, hay bug-free.

Trong th gii thc, thi gian v rng buc ti chnh lm cho khng th to ra nhng chng

trnh d n hon chnh. Thay vo , iu quan trng quyt nh da trn mc chp

nhn ca cht lng tha mn khch hng.

V d: khi khch hng quyt nh ng dng phi sn sng 23 gi trong ngy, b qua

thi gian vn hnh khng gim. Cht lng khc bao gm s ngi dng truy cp hin hnh,

thi gian ti a phi ch hon thnh cng vic trong ng dng (s phn hi), bo mt

ng dng, hay hn na.

c.Phn tch h tng c s hin hnh

Phn quan trng trong thit k gii php l phn tch k thut thay th. in hnh, gii

php phn mm c a vo hn l thay th h thng hin hnh. D n cn lm vic trn

phn cng v phn mm m ngi dng hin c. Bit c h iu hnh ang c ci trn

my ca ngi dng, loi mng ang s dng, v nu ngi dng ang chy phn

mm khng tng thch vi chng trnh mi hn. Nn b thi gian tm hiu my ch hinhnh,

h iu hnh, phn mm ang chy.

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Khi a gii php, nh rng c s h tng hin hnh m bo gii php ca chng ta c th

tng thch.

d. Phn tch nh hng k thut

Nu cn m rng chc nng cho h thng hin hnh, chng ta mong c thay i hthng c c vic ci thin h thng c v tch hp d dng hn h thng mi. V d, chc

nng ca chng trnh k ton lu tr d liu nh nh CSDL hng n tp tin Access.

to d liu truy xut hiu qu hn v tha mn yu cu ca gii php mi, chng ta

mi chuyn ton b d liu sang h qun tr csdl SQL Server. Vic suy ngh trc s tit

kim thi gian sau : tri qua thi gian tm hiu s khc bit v giao tc, bo mt, v nhng

chc nng khc gia k thut c v gii php mi.

Chng ta nn tm hiu th tc chuyn i d liu t k thut c sang k thut mi. mbo c php thc nghim nhng th tc ny, v c k hoch bo lu trong trng hp thc

hin vn ny b li. m bo chc chn nhng tc ng chuyn i trn mi thnh phn

ca h thng, khng ch phn t gn nht thay i.

1.1.3.Phn tch yu cu bo mt

Khi h thng lu tr, truy xut d liu c nhn nh thng tin nhn s, th tn dng,

doanh s bn hay thng tin ring t, chng ta cn c bin php m bo an ton nhng d

liu ny.

a. Xc nh vai tr

Ton b ng dng khng ch c 1 mc bo mt. Ngi dng cui ch cn quyn truy

xut gii hn vo h thng. Qun tr h thng, ngi thao tc vin cp nht, v ngi dng c

quyn truy cp cao hn mi cp . Bo mt da trn vai tr l k thut dng cp quyn

mc bo mt khc nhau tng ng quyn hn v chuyn nghip ca mi ngi dng

trong h thng.

Lu : Nhn bit nhng lp chnh ca nhng ngi dng cn truy cp n ng dng

ca chng ta. Gn tn vai tr cho mi lp ngi dng. Cui cng, gn mc ti thiu c th

truy xut n mi vai tr. Mi lp ngi dng nn c quyn truy xut n cng vic ca

h, v khng nhiu hn.

b. Xc nh mi trng bo mt ng dng

bo mt khng b gii hn ngi dng h thng. Ch ngi dng ng nhp vo ng

dng, ng dnng phi login kim sot ti nguyn chia s nh tp tin, dch v h thng,

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c s d liu. Mc kim sot ca ng dng c gi l ng cnh bo mt. Chng ta cn

phi lm vic vi nhiu ngi dng khc nh qun tr mng, cp quyn truy xut ph hp

ng dng chia s ti nguyn.

c. Xc nh nh hng bo mt

Nu cng ty c sn c ch bo mt thay vo h thng ca chng ta nn iu chnh

cho ph hp vi c ch c. Nu chng ta ang thc thi h thng bo mt mi hay mt h

thng khc, cn phi phn tch tc ng ca h thng trn h thng hin ti:

H thng mi c lm hng chc nng ca phn mm hin ti?

H thng i hi phi h tr thm mt phn ngi dng ng nhp m rng ?

H thng s kha mt vi ngi dng trn nhng tp tin hay nhng ti nguyn m h

c quyn truy cp trc y

d. K hoch vn hnh

Khi t chc pht trin v thay i, ngi dng mi c thm vo, ngi c c cp

nht v b i. Nhng thao tc ny i hi thay i CSDL bo mt, l ni thng tin ngi

dng v quyn hn truy cp ca h c lu. Nhng thng tin ny c lu tr hin thi.

Nu ngi dng c v tr a l khc nhau, vn phng khc nhau, chng ta cn ln k

hoch ti to c s d liu bo mt. S ti to l s thay i h thng d liu ti ni ny sao

chp n ni khc sao cho tt c thng tin bo mt c lu gi mi ni. Thun li vic to

bn sao l ngi dng c th ng nhp dng thng tin c lu v tr gn hn so vi v tr

a l. Nu mng WAN b ngng hot ng, v d ngi dng vn c th ng nhp. Vic

to bn sao cn c ln k hoch v vn hnh.

Lu : Chng ta ln k hoch cho iu kin khn cp phi lm g nu csdl bo mt b

ngt hay nu vic to bn sao b hng. i vi h thng bo mt b hng, chng ta cng nn

c c hai k hoch khn cp v th tc t ng ch n nhng vn chung nh mng b

hng.

d. K hoch kim sot v ng nhp

Mt h thng bo mt tt khng l c ch th ng. Thay vo , cha chc nng tr

gip kim sot hot ng ca h thng cho vn bo mt. Vn chung ca chc nng ny

l nht k. Ton b thao tc ca h thng c th c ghi nhn hu nh ton b s kin lin

quan n bo mt h thng. C th ghi nhn mi khi ng nhp, truy xut n mi ti nguyn

nhng iu ny him khi hiu qa; thng chng ta s ghi nhn mt s tp thng tin ny nhvic c gng ng nhp li.

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Lu : Nht k h thng t n th khng c ngha; chng ta phi k hoch kim sot

thng xuyn bi ta c th pht hin nhng nghi ng nhng mu nht k hot ng. Ngi

kim sot c hun luyn nn phn tch nht k trn c s thng xuyn, a ra nhng

ngh nu c bt k iu nghi ng.

e. Xc nh mc yu cu bo mt

Bo mt cng ging nh nhng phn khc trong thit k ng dng, l s cn nhc gia

hiu qu v chi ph. Nu h thng khng lu nhng d liu c tnh nhy cm cao. Cch tt

nht trin khai h thng l gi s xc thc ca ngi dng i hi lu tr. Nu chng

ta lu tr thng tin cn cho bo mt, chi ph cho bo mt thng tin c bit phi c kim

chng.

Khng c h thng no bo mt 100%. Chng ta phi xc nh mc ri ro bo mtc th chp nhn c. ri ro bo mt din t t l phn trm tng xng kh nng m bo

mt h thng khng bao gi t n. iu c th nhng ph tn xy dng h thng bo

mt 99%. Chng ta hay khch hng phi xc nh mc ri ro c th chp nhn c da

trn d liu nhy cm ca h thng.

f. R sot bo mt hin ti

Chng ta nn trung thnh tng ca yu cu bo mt ca ng dng. thi im phn

tch chnh sch bo mt hin ti ca cng ty xc nh bo mt c t n nhng nhu cu

ca h thng hay khng. Nu khng, tho lun vn vi ngi gch vc h thng bo mt

cng ty tm ra gii php mang li li ch trin khai m rng bo mt.

1.1.4.Phn tch yu cu tc

Tc ca ng dng c th i hi kh. i vi ngi dng, ng dng s hu nh

chy qu chm nhng chy nhanh ng dng thit k tt c th mang li gi tr

Lu : vic chy nhanh mt ng dng thit k km th d, nhiu ng dng c th chy

chm bi thit k thiu st, nhng khng bi khng tng thch gia phn ng v cc yu t

bn ngoi.

Chng ta nn nhn thc yu cu tc ng dng trc khi bt u qui trnh thit k.

Yu cu tc da theo cc mc sau:

Mi pht giao dch: cung cp dch v ph thuc vo s lng ln ngi dng, ng

dng phn tn dng nhng giao tc. S giao tc mi pht (TPM) l o tc h thng c

s d liu.

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Bng thng: ng dng phn tn lm nghn vic s dng mng. S phn hi ca ng

dng xc nh nh bng thng mng ( rng ca ng truyn mng). Bng thng thng

c o bng megabit mi giy.

Kh nng cha: Lng lu tr- c chnh v ph - sn sng i vi ng dng l vn

lu tm quan trng cho tc chung ca ng dng. RAM i hi ca ng dng gy ra nhng

khc bit ln cho tc ca ng dng.

Nt tht: Trong mi h thng, c phn gii hn tc h thng ni chung. V d CPU

tc nhanh cng khng ci thin g my nu phi ch d liu t mt cng qu chm.

Trong trng hp ny, cng s l nt tht ca ton b h thng. Khng th tng tc tr

khi nt thc c nhn bit, bi v ch c ci thin nt tht lm nng tc ph hp. Chng

ta c th nhn bit nt tht bng cch s dng cng c bo co h thng nh Mn hnh iukhin tc trn Window NT (Windows NT Performance Monitor).

Thut ng tc thng dng ng ngha vi s phn hi - s lng thi gian chim

gi phn hi li hnh ng ca ngi dng. C th lm cho ng dng xut hin phn hi

m khng cn tng tc . Tuy nhin, thi gian phn hi trung bnh ca ng dng l c tnh

quan trng, chng ta phi kt hp cht ch nhng mc tiu thi gian phn hi i vi yu cu

chung thit k.

Khng th ni v tc trong nhng ng dng phn tn m khng phn bit

quan trng: gia nhu cu cao v trung bnh. Ti mt s thi im - ti hay cui tun c l

ng dng s phc v vi s lng nh ngi dng, th tc n s trn trung bnh. thi

im khc, s lng ngi dng s cao hn v tc ng dng cho php. Mc tiu tc

bao gm c mc tiu tc trung bnh v cao.

1.1.5 Phn tch yu cu vn hnh

Chng ta c th gim bt chi ph vn hnh theo nhiu cch.Cch tt nht gim chi

ph vn hnh l m bo chng trnh c kim th v chy debug trc khi a vo trin

khai. Chi ph trin khai c th c gim bt bi phn phi trc tuyn hay nhng th tc t

ng ci t, v qui trnh vn hnh c th t ng bng cc qui trnh tin hc. Mc v tr v

hun luyn i ng l vn xem xt quan trng: i ng nhn vin cng c hun luyn k

v su th vn cng nhanh chng c sa i.

Trong trng hp phn cng, phn mm l thnh phn c mua ch khng c pht

trin, chng ta c th nhn s chp thun vn hnh t nh xng hay ngi y thc ca snphm. Vn hnh sn phm trung gian tit kim cho chng ta chi ph thu mn nhn vin

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mi hay hun luyn li nhng nhn vin c duy tr mt hay nhiu thnh phn ca h

thng.

Gim chi ph vn hnh i hi s t tha mn li nhun trong thi ngn i vi nhng

li ch trong tng lai. Gim chi ph vn hnh lu di thng i hi u t n u trong t

ng ha phn cng v phn mm.

1.1.6 Phn tch kh nng m rng yu cu

Qua thi gian, nhng yu cu gii php s thay i. Ngi dng cn nhng chc nng

mi, cc quy lut t ra s b sa i, v phn cng phn mm nn mi thay i theo. ng

dng thit k tt l c kh nng m rng c n c th uyn chuyn ci thin m khng

phi vit li hon ton. Kh nng m rng ca ng dng b o ngc so vi lng cng vic

cn hon thnh thm nhng c trng mi.

Kh nng m rng c th t c thng qua nhng ngha khc nhau. Mt cch t

nhng kh nng hn nh l lu tr thng tin quy lut t ra trong c s d liu hn l lp

trnh chng trong i tng nghip v. Theo cch , nu s quan trong hay th tc thay i,

n c th thay i trong CSDL m khng thay i m ngun. Cch khc l t m ngun vo

trong on script c lm r hn bin dch chng trnh; on script c th b thay i mt

cch d dng khng i hi bt k bin dch hay ci t li tp tin nh phn

Lu : cch tt nht t c kh nng m rng l ngt ng dng thnh nhng i

tng thnh phn, mi thnh phn hon thnh mt nhim v ring l. Nu nhng yu cu ca

nhng nhim v c bit thay i, i tng tng ng c th b thay i v bin dch li m

khng gy nh hng bt k i tng khc. Nhng i tng c thm vo d dng. i

tng nghip v c nhng thun li c lm hiu qu hn nhng phng php khc trong

khi vn m bo tt kh nng m rng.

1.1.7. Phn tch nhng yu cu sn cNhng ng dng phn tn c thit k chy mi ngy. N cn thit cho s thnh

cng ca doanh nghip. Nh vy, chng c mc sn sng cao nn trnh thng bo tr,

sa cha, pht sinh khng theo k hoch.

R rng, i vi nhng ng dng mang tnh sn sng, n khng c gy ra li. Khng

c ng dng no l khng c li, ng dng phi c bo lu chng c th hot ng

thm ch khi bug xy ra trong mt phn ca chng trnh. Th d, nu ngi dng gy ra li

cho chng trnh th ch mt phn chng trnh phc v cho ngi dng b hng, khng

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nh hng ngi dng cn li ang ni kt. Bt k thnh phn ng dng no hng hay khng sn

sng th nn khi ng li ngay khi c th.

Vic bo tr c k hoch cng tc ng n tnh sn sng. Mt my ch cha ng dng

l tng lun c bn sao lu c th khi ng khi my ch bo tr. ng dng c mc sn

sng cao c cch lun phin kt ni mng trong trng hp mng WAN, LAN ngng hot

ng

Lu : Tnh sn sng lin quan n nghip v. Tnh sn sng ca ng dng cng cao,

gi tr ca ng dng cng cao. Chng ta phi xc nh bao nhiu gi trong ngy ng dng cn

c thao tc; gi no l quan trng so vi cc gi trong ngy. Cn nhc gi tr ca vic tng

tnh sn sng i vi gi tr d n ca thi gian down ng dng. Nhng h thng trng yu,

gi tr i vi cng ty bt k thi im down no hon ton iu chnh chi ph thit k 100% ng dng sn sng. ng dng khc n gin cn tr nn sn sng hu ht mi lc.

1.1.8. Phn tch yu t con ngi

Thit k ng dng c gim st bi nhiu ngi lp trnh l phn quan trng ca yu

t con ngi. Chng ta nn xc nh kinh nghim g m chng ta mun ngi dng c. Vi bt

c ng dng no khc, kinh nghim ngi dng cng tt th chi ph cng cao.

Bt u nh ngha mc tiu ca ngi dng. Xc nh ngi dng vi nhng nhu cu

c bit nh th no. Chng ta cn iu tit ngi dng qua vic iu tit nghe v nhn, hay

ngi dng ni ting nc ngoi. Ph thuc vo v tr a l ca ngi s dng. Chng ta cn

sa i ng dng thch ng theo v tr a l. Cn iu chnh nhu cu lt qua ca ngi

dng, ngi khng cn s ni kt chc chn hay kh nng tr li li.

Xem xt mc chuyn nghip gia ngi dng. Vi chuyn vin hc nhanh hn vi

giao din thit k tt v tr gip trc tuyn Help online. Ngi dng vi k nng km hn

tng tc qua s dng wizard, tr gip online, hay ch dn. Hun luyn khch hng trong ng

dng cng nn cn nhc chn la.

1.1.9. Phn tch yu cu tch hp

Nu gii php giao tip vi ng dng k tha, vic truy xut CSDL tn ti, hay vic

chuyn i d liu c sang khun dng mi, bn cn phi a k hoch tch hp ng dng

vi phn mm c. iu ny c lm thng qua kt ni ca hng trung gian nh trnh iu

khin thit b kt ni csdl (ODBC), nhng chng ta cng cn vit kt ni v nhng tin ch

chuyn i

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Khi pht sinh nhu cu ln hn, c s d liu phi thit k li. K thut d liu mi hay

v l a nhu cu ci thin CSDL bn di ng dng. Nhng ci tin phi c cn thn bi

chng ph v tt c m ngun CSDL hin ti. Trc khi ci tin khung d liu, m bo

nhng phn m ngun hin ti c th truy xut n CSDL. Tt c m ngun hin ti phi

c sot li, c th vit li.

1.1.10. Phn tch thc tin nghip v tn ti

Phn nh ngha trong qui tc nghip v lin quan n s hiu bit ng cnh

trong nhng qui tc thao tc. Hiu c nhng thc t nghip v ca doanh nghip c th

gip chng ta trnh c sai st thm ch gip tm cch tt hn, hiu qu hn ca t ng ha

tin trnh nghip v. Hiu c vn hp l di mi tin trnh c th ngn bn gy ra li

mt cch ngy ng dn n tranh chp.Hiu c cu trc t chc v s lm vic nghip v l quyt nh. Khng hiu r

rng s t chc, khng th em li s chp thun ph hp cho thit k ng dng

ca chng ta hay thng tin theo kp trn thit k hay nhng vn trin khai. hnh t

chc cng gip cho tm kim thng tin ngi n danh phn hi li chc nng ca ng dng

m khng dng bt ca chnh h.

C c ng dng t giai on pht trin n sn phm i hi s hiu bit mng v

chnh sch h tng ca cng ty. Bit c ai l ngi chu trch nhim bo tr, bo mt, tnh

ton vn, kh nng phn hi tng tc trn mng. Hc nhng tin trnh v chnh sch lin

quan chy trn ng dng mi. Tm ra loi kim sot cht lng v dch v kim th sn sng

trong khi chng ta kim th trn chnh phn mm, ta c th t ng ti nguyn hay dnh cho

b phn kim tra cht lng ty s dng. Chng ta c th yu cu phng php thit k c

bit hay trin khai thc t. Chng at cng i hi chc chn k hoch c kt cht vi ngn

sch

Cui cng, gi nhng nguyn tc ct li: Hc nhu cu khch hng, c gng thc hin

chng. iu ny c th tr nn kh khi khch hng khng bit nhu cu ca h l g, nhng

l cch dn n ng dng thnh cng.

1.1.11.Phn tch yu cu kh nng quy m

Nu ng dng thnh cng s hp dn ngi dng hn. c bit, nu ng dng chy

trn mi trng web nh Internet th s thnh cng ng ngha vi tng nhu cu. ng dng

phi c thit k c quy m- n phi h tr nng cp cho php phc v nhiu ngi hn.

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Mt cch n gin nng cao ng dng l mua CPU nhanh hn, nhiu RAM, kt ni

mng tt hn. Tuy nhin vic tng cng my n chy nhanh hn. Thc s nhng ng dng

c th nng cp phi thm vo nhiu dch v pha my ch. iu ny c ngha ng dng c th

chy trn nhiu my tnh cng mt lc, s phn phi vic ti xung ca ngi dng v x

l thi gian qua nhiu my ch. iu ny s gia tng ng k tnh phc tp, v vy mt ln

na tnh thun tin kh nng quy m phi c cn nhc i vi gi tr cung cp. Tuy nhin,

ng dng nh Miscrosoft Transaction Server gim ng k chi ph pht trin ng dng phn

tn bi qun l v mt logic ca phn tn t ng.

1.2 Xc nh yu cu

Mc tiu c a vic xc nh yu cu:

Xc nh tht chnh xc v y cc yu cu t ra cho phn mm s c xy dng.

Kt qu nhn c sau giai on xc nh yu cu:

1. Danh sch cc cng vic s c thc hin trn my tnh

2. Nhng m t chi tit v cc cng vic ny khi c thc hin trong th gii thc.

Qua bc u hnh thnh thng tin khi qut v cc hot ng trong th gii thc.

1.2.1 Yu cu v m t yu cu

Yu cu (hay yu cu phn mm) l cng vic mun thc hin trn my tnh. Nhng

cng vic ny phi xut pht t thc t ch khng thun ty tin hc

M t yu cu l m t y cc thng tin lin quan n cng vic tng ng. Cc

m t ny dng lm c s nghim thu v nh gi phn mm khi c chuyn

giao.

Cc yu cu ca phn mm cn c m t tht r rng, c th, y v chnh xc cc

thng tin lin quan n cng vic tng ng. Vic m t s si, m h yu cu phn mm

s dn n vic hiu nhm gia chuyn vin tin hc (ngi thc hin phn mm) v khch

hng (ngi t hng thc hin phn mm). Nhiu cng sc v chi ph phi hao tn do cc

hiu nhm nh th.

Cc loi thng tin chnh cn c quan tm khi xc nh yu cu phn mm:

Tn cng vic ng vi tng yu cu

Ngi hoc b phn s thc hin cng vic a im thc hin cng vic

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Thi gian thc hin cng vic

Cch thc tin hnh cng vic cng vi cc quy nh lin quan

Sau y, tng loi thng tin s ln lt c xem xt chi tit:

a. Tn cng vic.

Cn xc nh c th, trnh dng cc tn chung chung, m h

V d: xt mt s tn cng vic sau:

Qun l c gi: chung chung, m h; c th nh vic ng k mn sch, gia hn th

c gi, tr sch

Qun l sch: chung chung, m h; c th nh nhp sch vo kho, tra cu sch, cho

mn sch, nhn tr sch, thanh l sch.

b. Ngi thc hin.

Cn xc nh chnh xc ngi hoc b phn s thc hin cng vic trn my tnh (cn gi

l ngi dng phn mm hay ngi dng).

Nhng ngi dng c vai tr v cng vic thc hin tng t nh nhau s c xp

vo cng mt loi ngi dng (thng thng mt loi ngi dng s tng ng vi mt b

phn trong th gii thc).

Cng mt cng vic c th c nhiu loi ngi dng khc nhau thc hin v ngc li,

mt loi ngi dng c th thc hin nhiu cng vic khc nhau.

c. Thi gian, a im.

Cn xc nh chnh xc a im, thi im tin hnh cng vic. Cc thng tin ny s

c ngha nht nh trong mt s trng hp c th.

d. Cch thc tin hnh v cc quy nh lin quan.

y l phn chnh yu khi tin hnh m t yu cu. i vi loi thng tin ny cn c

bit quan tm n mt s yu t sau:

i. Cc quy nh cn kim tra khi thc hin cng vic ghi nhn thng tin

V d : Quy nh v vic mn sch khi cho c gi mn sch: ch cho mn sch i

vi nhng c gi c th c gi cn hn, s sch ang mn cha n 2 v khng c sch

mn qu hn.

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V d : Quy nh tnh hp l ca phn s trong vic ghi nhn bi ca gio vin v bi

gii ca hc sinh: phn s phi c mu s khc 0

ii. Cc quy nh, cng thc tnh ton khi thc hin cng vic tnh ton

V d : Quy nh tnh tin pht tr sch tr khi thc hin vic tr sch: mi ngy tr trpht 1500 ng/ngy. T ngy tr tr th 10 tr i s pht 5000 ng/ngy v thu hi th c

gi 2 tun.

V d: Quy nh tin lng khi thc hin cng vic tnh lng nhn vin cho 1 cng ty

* Lng ca nhn vin thuc b phn vn phng c tnh theo cng thc:

Tin_Lng = (S_Ngy * Mc_Lng )/22 + Tin_Thng

+ Tin_Pht

mi ngy lm thm thng 30.000

mi ngy ngh vic pht 50.000

* Lng ca nhn vin thuc b phn sn xut c tnh theo cng thc:

Tin_Lng = S_Sn_Phm * n_Gi

Bit rng mt sn phm phi tri qua 3 cng on sn xut:

cng on 1: 200 ng/sn phm



1.2.2 Phn loi yu cu

S cy phn loi yu cu

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YU CU

(1)Yucuchcnng

(2)Yucuphichcnng

(3)

Yucuchcnngnghipv

(4)

Yucuchcnnghthng

(5)

Linquannngidng

(6)

Linquannchuynvintinhc

(7)Lutr (11)Mitrng (16)Tnhtinha (20)Tisdng

(8)Tracu (12)M phng (17)Tnhtindng (21)Tnhbotr

(9)Tnhton (13)Tng (18)Tnhhiuqu

(10)Ktxut (14)Phnquyn (19)Tnhtngthch

(15)Saolu


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c t chi tit tng l o i yu cu:

(1) Yu cu chc nng l danh sch cc cng vic s c thc hin trn my tnh cng vi cc

thng tin m t tng ng.

(2) Yu cu phi chc nng l cc yu cu lin quan n cht lng phn mm, l s rng buc

cch thc thc hin cc yu cu chc nng.

(3) Yu cu chc nng nghip v l cc chc nng ca phn mm tng ng vi cng vic c tht

trong th gii thc.

(4) Yu cu chc nng h thng l cc chc nng phn mm c pht sinh thm khi thc hin

cng vic trn my tnh thay v trong th gii thc hoc cc chc nng khng tng ng vi

bt k cng vic no trong th gii thc.

(7) Chc nng lu tr: Tng ng vi cng vic ghi chp thng tin trn s sch (km theo cc quy

nh khi ghi chp).

V d:

- Ghi nhn vic cho mn sch ca mt th vin theo quy nh mn.

- Ghi nhn bi gii bi tp v phn s theo quy nh v phn s,cch bin i phn s

tng ng, cc php tnh trn phn s,

(8) Chc nng tra cu: Tng ng vi cng vic tm kim, theo di hot ng v xem thng tin

v mt i tng.

V d:

- Tm ti khon v xem tnh hnh gi rt.

- Tm sch v xem tnh trng sch

- Tm hng ha v xem tnh trng ca hng ha (s lng tn kho, lng nhp, thi gian

nhp,).

- Tm bi ging l thuyt v phng trnh, bt phng trnh v xem ni dung tng ng.

(9) Chc nng tnh ton: Tng ng vi cng vic tnh ton (theo quy nh v cng thc cho

trc).

V d:

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- Tnh im trung bnh mn hc ca hc sinh theo quy nh h s cho cc t kim tra.

- Xp th hng cho cc i bng sau mt lt thi u theo quy nh ca ban t chc gii.

- Tnh tin pht tr sch tr theo quy nh pht ca th vin.

- Tm nghim ca phng trnh bc hai theo phng php gii phng trnh bc hai.

(10) Chc nng kt xut : Tng ng vi cng vic lp bo co (theo biu mu cho trc)

V d :

- Lp bng xp hng cc i bng sau mt lt u.

- Lp bo co thng k v s lt mn sch theo tng th loi trong nm.

- Lp bo co thng k v t l xp loi hc sinh theo tng lp, tng khi.

(11) Chc nng mi trng : nh cu hnh thit b, ngy gi, s ngi lm vic,

V d: S lng ngi lm vic, chn loi my in, kh giy, nin kha hin hnh,

(12) Chc nng m phng: M phng hot ng ca th gii thc

V d : - M phng mt tai nn my bay, xe t, trn ng t

(13) Chc nng t ng: T ng thng bo, nhc nh ngi dng. V

d :

- Nhc nh th th gi giy bo i sch khi c c gi mn qu hn.

- Bo ng khi khch hng thiu n qu lu hay s tin n qu ln.

(14) Chc nng phn quyn : Phn quyn s dng gia cc loi ngi dng.

V d: Phn quyn cho 3 loi ngi s dng trong phn mm qun l th vin:+ Qun tr h thng: c quyn s dng tt c cc chc nng.

+ Th th: ch s dng cc chc nng lin quan n vic cho mn v tr sch.

+ c gi: ch s dng chc nng tra cu.

Trong phn mm qun l bn hng, vic phn chia kh nng truy cp d liu nhp xut

cho tng nhm ngi s dng s trnh vic iu chnh s liu khng thuc phm vi qun l ca

ngi s dng nh nhn vin thu ngn ch c php lp v iu chnh cc ha n bn hngtrong ca lm vic ca mnh. Ca trng v b phn qun l quy c th tham kho lng hng

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tn kho nhng khng c php iu chnh lng hng nhp, khng c tham kho vn hng

xut, kt qu kinh doanh,

(15) Chc nng sao lu : Sao lu, phc hi d liu.

V d: Sao lu thng tin v cc hc sinh ra trng v ch phc hi li khi cn thit

(16) Tnh tin ha: y l cc yu cu lin quan n vic cho php ngi dng thay i li cch

m t ca mt yu cu chc nng (cc quy nh, quy tc tnh ton), mt biu mu no khi

ang dng phn mm c chuyn giao. iu ny i hi phi c d kin v cc thay i

trn thnh phn d liu v x l.

V d :

- Cho php thay i quy nh v s sch cho mn ti a, hay mc pht khi tr tr.

- Cho php thay i cc bin trong quy nh v xp loi hc sinh.

(17) Tnh tin dng: l cc yu cu lin quan n hnh thc giao din ca phn mm, th hin

s t nhin, d s dng, d hc, y thng tin,...

V d :

- Giao din nhp ha n bn hng dng form, dng nhp th hin bng sng v bo li khi

s liu nhp lm s lng tn kho m (phn mm qun l hng ha).

(18) Tnh hiu qu : y l yu cu lin quan n thi gian thc hin cc chc nng phn mm,

dung lng lu tr, chi ph s dng ti nguyn h thng nh s dng ti u cc khng gian, thao

tc thc hin nhanh ...

V d: Thi gian tra cu sch, tra cu c gi khng qu 10 giy.

(19) Tnh tng thch: l cc yu cu lin quan n vic chuyn i d liu gia phn mm ang xt

v cc phn mm khc, s nht qun gia cc mn hnh trong h thng.

V d : - Cho php chuyn tt c cc bo co sang nh dng file Excel

- Cho php nhp thng tin sch mi t tp tin Excel hay t thit b c m vch.

- Cho php thc hin chc nng bng ging ni.

(20) Tnh ti s dng: (do chuyn vin tin hc m trch)

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(21) Tnh bo tr: (do chuyn vin tin hc m trch) l cc yu cu cho php thay i m khng lm

nh hng n phn mm

1.2.3 Cc bc xc nh yu cu

Qu trnh thc hin xc nh yu cu : gm 2 bc chnh nh sau

B c 1 : Kho st hin trng, kt qu nhn c l cc bo co v hin trng.

B c 2 : Lp danh sch cc yu cu, kt qu nhn c l danh sch cc yu cu s c

thc hin trn my tnh.

i tng tham gia xc nh yu cu: gm 2 nhm ngi:

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Chuyn vin tin hc: nhng ngi hiu r v kh nng ca my tnh. H phi tm

hiu tht chi tit v cng vic ca nh chuyn mn nhm trnh s hiu nhm cho

nhng bc phn tch sau ny.

Nh chuyn mn: nhng ngi hiu r v cng vic ca mnh. H cn lng nghe kin ca cc chuyn vin tin hc m bo cc yu cu ca h l c th thc

hin c vi chi ph v thi gian hp l.

Hai nhm ngi ny cn phi phi hp tht cht ch c th xc nh y v chnh xc

cc yu cu.

Sau y, chng ta s phn tch chi tit tng bc quy trnh thc hin.

1.2.3.1 Kho st hin trngCc chuyn vin tin hc s tm hiu hin trng v cc cng vic ca cc nh chuyn mn.

a. Cc hnh thc thc hin ph bin:

Quan st : theo di cc hot ng ang din ra th gii thc c lin quan, c th tin

hnh ghi m, ghi hnh i vi nhng tnh hung mang tnh phc tp, quan trng, cn s

chnh xc cao.

V d:- Ghi hnh qu trnh giao dch ca mt nhn vin ngn hng vi khch hng ti mt ngn

hng X.

- Quan st thao tc cho mn sch ca mt th th ti mt th vin Y

Phng vn trc ti p : t chc phng vn bt u t cp lnh o dn xung cc v tr

cng vic. C th s dng cc bng cu hi c sn cc cu tr li cho i tng c

phng vn la chn,

Thu thp thng tin, ti li u : cc cng thc tnh ton, quy nh; cc bng biu, mu

giy t c t nhiu lin quan.

V d:

- Mu ha n v cc quy nh lp ha n bn hng ti mt ca hng Y.

- Phiu mn sch ti th vin ca trng i hc Z.

b.Quy trnh thc hin:

Tm hiu tng quan v th gii thc: bao gm

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- Quy m hot ng.

- Cc hot ng m n v c tham gia.

Tm hiu hin trng t chc (c cu t chc)

Ngi tin hnh kho st hin trng cn hiu r c cu t chc cc b phn ca th gii

thc, c bit l 2 yu t: trch nhim v quyn hn. S hiu r c cu t chc gip xc

nh b phn no s s dng phn mm c th ln k hoch tip tc kho st chi tit

hn b phn .

C cu t chc bao gm:

- i ni.

- i ngoi.

- Cc chc danh (V d: nhn vin nhp liu, th th, nhn vin bn hng, ). S

dng cc hnh v li c cu t chc.

Tm hiu hin trng nghip v

Thng din ra ti cc v tr cng vic. Vi b phn c chn kho st chi tit, ngi

thc hin kho st cn lp danh sch cc cng vic m b phn ny ph trch, sau tm

hiu cc thng tin chi tit cho tng cng vic (thng tin m t yu cu phn mm).

Vic tm hiu da trn cc sau:

- Thng tin u vo.

- Qu trnh x l.

- Thng tin kt xut.

Sau tin hnh xp loi cc nghip v vo 4 loi sau nhm trnh thiu xt khi tm hiu cc

thng tin:

- Nghip v lu tr.

- Nghip v tra cu.

- Nghip v tnh ton.

- Nghip v tng hp, thng k

1.2.3.2 Lp danh sch cc yu cu

c c danh sch y v chnh xc cc, qu trnh lp danh sch cc yu cu cu

theo cc bc sau:

Xc nh yu cu chc nng nghip v

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