Giáo trình dành cho kỹ sư cntt cơ bản

Bon tap sau day bao quat toan bp noi dung cua tri thuc vk ky nang co ban can cho viec phat trien, van hanh va bao tri h£ thong tin: Quyen 3: Thiet ke trong va lap trinh — Tong lugrng tr

I TRUNG TAM SAT HACH CONG NGHE THONG TIN VA HO TRO DAO TAO

® ban quan i v khu co n g nghe cao hoa lac - b o khoa hoc va co n g nghf

ViTEC

GIAO TRINH DANH CHO KY SIT CNTT CO BAN

Tai lieu IuTj hanh noi bo

Ban a

Mac lye ¥ ■;

Gi-Vi thieu ’

1 Phat trien he thong '

ji6i th ieu

1.1 Phuong phap lu$n Phat trien he thong .

1.1.1 Vai tro cua to chuc phat trien he thong 8

1.1.2 Mo hinh phat trien phan mem 10

1.1.3 V6ng d6i phan m em 16

1.1.4 Dung lai Phan m em t 25

12 Phan tfch yeu cau vh phuong phap thiet k e 2;

1.2.1 Phuong phap l^p bieu do 28

1.2.2 Lap bieu do phan ti'ch/thi£'t ke 30

1.2.3, Phuong ph&p thiet k£' 37

13 Ngon ngu l$p trinh 5.

1.3.1 Thupc tinh chuong trinh 57

1.3.2 Kieu du lieu 58

1.3.3 Cau true dieu khien 59

1.3.4 Phan tich cu phap 61

1.3.5 Phan lo^i ve ngon ngu* lap trinh

1.3.6 Kieu va d&c trung cua ngon ngu lap trinh 70

11 Ky thuat lap trinh

1.4.1 Lap trinh thu tyc .77

1.4.2 I ap trinh h am 77

1,4.3 - 1- «?p frinK ioj»k‘ - • • 78

1.4 4 Lap trinh huong doi Uft/ng .79

1.5 Phuong phap kiem thtr va kiem diem 80

1.5.1 Phuong phap kiem thtr W i 5.2 Phirong phap ki£m diem S7 1.5.3 Thiet ke kiem thu va phuong phap quan ly 90

1.6 Moi truong phat trien 93

1.6.1 Cong cm ho U q phat trien 93

1.6.2 E U C v a E U D 100

1.7 Quan ly phat trien 102

1.7.1 L?p ke hoach d y an 102

1.7.2 L|p ke ho$ch, quan ly va danh gia chat luong 102

1.7.3 Quan ly tien trinh 105

1.7.4 Nang suat phan mem 109

1.7.5 To chuc phat trien 113

1.8 G6i phan m em 119

1.8.1 D$i cuong ve goi phan mem t 119

1.8.2 Phan lo^i cac goi phan m em 120

1.8.3 Cong cy quan ly san xu at 121

1.8.4 Vi dy ve viec dimg hieu qu£ goi phan mem 122

1.8.5 Phan mem nh6m - Groupware 123

1.8.6 Cong cy O A 124

Bai t?p 129

2 V£n hanh va bao tri he thong 135

Gjoi thi£u 136

2.1 Van hanh he thong 137

2.1.1 Quan ly tai nguyen 137

2.1.2 Quan Iv van de 139

2.1.3 Quan ly tien nghi 141

2.1.4 Quan ly an ninh 143

2

z 1.6 ly du p h i I4 j

.2 i./ ui.icii'i ly KdilLi KiiuC * i46

2.2 8 £ j tri he thong 148

2.2.1 Bao tri la gi? 148

2.2.2 Tam quan trong cua cong vif c bao tr i 149

2.2.3 Chi phi bao tri , 149

2.2.4 Nhifm vy bao tri 150

2.2.5 To chuc bao tri 154

2.2.6 Cac kieu b£o tri 157

2.2.7 Bao tri phan cung va M o tri phan mem 158

Bai tip 161

C?p nhit x u ly thong tin va an ninh 164

Gidi thi^u ^ 165

3.1 Lirft vuc ung dyng cua h£ thong may tinh 166

3.1.1 Tong quan ve kinh doanh di|n tir (e-business) 166

3.12 Tong quan ve e-learning 168

3.13 Tong quan ve chinh phu dien tir (e-goventment) 173

3.2 An ninh 178

3.2.1 An ninh Internet 178

Tra ldi lai tap 187

4.1 Tr4i£N cho Quyen 2 Chuong 1 (Phat trien phan mem) 187

4.2 Tra ids cho Quyen 2 Chuong 2 (Bao tri va v£n hanh he thong) 202

G!6i th?eun

Loat sach giao khoa nay da dupe xay dyng dya tren Chuan Ky nSng Ky sir Cong nghe thong tin dupe dira ra cong cpng vao thang 7 nam 2000 Bon tap sau day bao quat toan bp noi dung cua tri thuc vk ky nang co ban can cho viec phat

trien, van hanh va bao tri h£ thong tin:

Quyen 3: Thiet ke trong va lap trinh — Tong lugrng tri thiic cot loi va thyc hanh

Cuon sach nay neu nhung giai thich de myt cadi c6 he thong, de nhung nguoi dang hoc ve phat trien, v?n hanh v<i bao tri he thong lan dau tien co the de dang thu dupe nhung tri thuc trong cac linh vyc nay Cuon sach nay bao gom cac chuong sau:

Chuong i : Phat trien he thong

Chirong 2: V?n hanh vh b io tri he thong

M mc dich cua chuong

Voi cac cong ty, dieu thiet yeu la thu duoc ioi nhu£n Tuy nhien, voi tinh hinh kinh te hon lo$n hifn nay, rat kho du doan xu hudng tuong lai Trong tinh hinh nhu vay, cac he thong xu ly thong tin trd thanh quan trpng song con cho hoat ddng nghiep vu, va do do la mau chot cho su ton tai cua cong ty Cac ky su xir ly thdng tin, tat di cac he thong thiet ke

va phat trien xir ly thdng tin, da ngay cang trd nen quan trpng.

Chuong nay ndi ve luong phat trien sir dyng md hinh thac do, cung cap mpt co sd cho vifc phat trien h f thong, cac mdi trudng phat trien, cac hf thong quan ly, va vifc sir dyng cac goi phan mem Ve chi tiet, bao gom cac m yc sau:

• D$i cuong ve cac phuong phap iu$n phat trien hf thong, va cac tien trinh phat trien su dyng mo hmh thac do.

• Cach lap bieu do phan tich yeu cau, va cac cdng nghf thiet ke khac nhau.

• Cac ngon ngu l$p trinh va ky thu^t lap trinh.

• l am quan trpng cua kiem thir, va cac phuong phap thiet ke cac trudng hpp kiem thu.

• Cac cong cy dupe dung trong mdi trudng phdt trien, v^ cac ky thuat va hf thong cho vifc quan ly phit trien.

• Cac kieu goi phan mem va cach sir dyng chung.

Giai thicu

Nam muoi nam da troi qua ke tiV kin to may co ten la "may Imh" xuat hien Ban dau khong co ly thuyet bay phuong phap lu$n nao cho viec phat trien he thong, tno nen Vi^c phai trien tuy thupc chu yeu vao "tai nghe" cu«i ky su Dieu nay hoan toan tuong tu nhu nguoi thy mpc xira kia lain nha theo "true giac" va "kinh nghiem" cua hp Tuy nhien, cac

he thong da dan tro nen ngay mpt Ion hon, su mo rpng va viec thay doi cac he thong hien co da tro thanh can thiet, song song voi viec phat trien cac he thong moi Them vao do, nSng suat phat trien da tro nen cao hon Tinh huong nay

da dat toi cho ma chi dung "tai nghe" thoi la hoan toan khong du, dan toi viec mac nhien phai co cac ly thuyet phat trien he thong, va cac phuong phap kv nghe de thuc hien cac ly thuyet do.

Ngoai nhung phuong phap quy uoc, nhung phuong phap va ly thuyet phat trien inoi dupe dua ra da cho phep d^t dupe n&ng suat cao hon, va ciing than thien hon voi nguoi dung.

Chuong nay de e£p den cac ly thuyet co so cho viec phat trien he thong, va cac phuong phap lu£n cua chung Viec su dung co hieu qua cac goi phan mem moi va cac phuong phap kiem diem cot yeu cua cong viec phat trien he thong cung dupe trinh bay trong chuong nky.

1.1 Phuong phap luan Phat trien he thong

Ngoai cac phuong phap iugn phat trien he thong, myc nay rung giai thi<?u ve moi quan he giua cac h£ thong doanh nghiep, cong nghe thong tin va cac phuong phap phat trien chinh.

(1) Hoat tf§ng xi nghi$p va h$ thdng tin

De tao ra su phat trien lien tyc cua xi nghifp can rat nhieu no iuc, trong do vi?c su dyng Cong nghe Thong tin (CNTT)

co tam quan trong song con.

Voi cac xi nghiep, co hai kieu thong tin:

• Thong tin n$i bp* Thong tin sinh ra qua cac hoat dpng nghi£p vu, bao gom c i c a c hoa don, hieu mau va tai lieu quin ly duoc dung trong ban hang, d$t hang va ke toan.

• Thdng tin ngoai: Thong tin phat sinh ra tuy thuQC vao tinh trang kinh te xung quanh cong ty, ke ca vi§c b in san pham, xu hirdmg cac nganh cong nghiep c6 lien quan, dong thai cua cac cong ty c^nh tranh, va cac giao djch voi cac cong ty lien quan.

Doanh nghi£p se su dyng die thdng tin tren trong ho$t dQng h in g ngay cua minh mgt cach hi£u qua, v6i he thong thong tin lam phuong ti§n H§ thong thong tin ducrc pHSn thinh hai I091:

• H f thong xur ty tic nghi^p: D uqc dung de ho tro cho die hoat dong hing ngay v i cung cap du lifu quan ly doanh nghiep H£ thdng nay thi/c hien vi§c xir ly thdng tin deu ky nhim ting nin g suat v i dii tidh hieu qua v|n hanh doanh nghi^p.

• thdng tin chien \\tQc: De d$t dupe cac myc dich da dang, dieu quan trong li su dyng dupe lai nguyen sin

co, con nguoi, v&t tu va tien bac, theo cach hieu qua nhat He thong nay cung cap thdng tin can cho vi£c quin iy cac tai nguyen noi tren H§ thong nay chu yeu duoc dung de tao ra cac bao cao tir g6c dd quin ly.

Hinh 1.1.1 H f thong tin chien htgc va h f xti ty tac nghify

L£m k£ ho^ch chi6n luge Ph§n tich thj tru’dmg Phan tich ban h&ng Quan If ngan sach vci chi phi

c 'Cfl o>

& § -C

O £

CD Cb

b

n

c

<He thong tin chien lirpc>

<H$ xi> li tac nghi£p>

Muc dich cua tung he thong bao gom:

<He thdng xu iy tic nghiep>

• Lam giam nhan cong cho nhurtg thao tac 06 ii.en quan

• Lam giam vi^c xu iy nghiep vu

» Larn giam thai gian giao hang

• Thyc hi?n cac thao tac khong giay td

<H£ thong tin chien luy»c>

• Lam tang doanh so ban hang

• Cai thifn hieu qua ban hang

• Cai thien sir thoa man cua khach hang

* Noi chung, mQt to chuc chju trach nhiem phat trien c<ic he thong xu ly thong tin duyc goi la to chuc phat trien he thong (ho$c gpi bang ten khac tuong ty nhu vay), cac ky su* he thong (SE) va cac lap trinh vien thupc ve to chuc nay Mgt to chuc su dyng cac he thong duoc phat trien dupe gQi la to chuc ngudi dung.

(2) Tien b$ trong CNTT vh To chuTc Phat trien H£ thong

(D Tien bQ trong cdng ngh$ thdng tin

Nhung budc tien mdi day trong cong nghe & ra't dang ngac nhien va da dang Trong so do, nhung tien bQ sau dSy duyc

Su cai thien hieu nSng dia ca may tinh ca nhan vh tram lam viec, va viec giam gia dang ke cua chung la mdt dieu dang

kinh ng$c Nhfrng thao tac ma co thdi chi thyc hien diryc vdi may tinh Idn thi bay gid da co the duyc thyc hien b3ng nhung may tinh nhd hon.

b Su dyng ryng rai cic g6i phan mem

Do sy phat trien nhanh chong cua cac goi phan mem, nen nhung goi phan mem Quan trj Co sd Du lieu Quan he (RDBMS : Relational Data Base Management System) va bAng tinh nay da sin co, va vi$c tfch hop chung vao mQt so'he thong cung trd nen kha thi.

c Tien by trong cong nghe mang

Doi mdi cdng nghe trong linh vyc thong tin va truyen thong, bao gom sy ket hop Mang Cyc by (LAN - Local Area Network) va Mang Dien rpng (WAN - Wide Area Network), va viec xay dyng cac mang nyi bQ (intranet) va mang ngoai bQ (extranet mang duQc tao ra hang each md rQng mang noi by ra ben ngoai cong ty), la rat dang chu y

Cong nghe da djch chuyen tir cach tiep can hudng quy trinh sang cach tiep can hudng du lieu (DOA - data oriented approach) Ket qua la cac ky phap duyc tao ra de bieu dien cho cac thiet ke cd cau true nhu Bieu do Luong Du liei> (DFD - Data Flow Diagram), Bieu do Thyc the - Quan he (ERD - Entity-Relationship Diagram), Cap bac CQng vdi Va;

Xu ly Ra (HIPO - 1 lierarchy plus Input I’rocess Output), da duoc chap nhan ryng rai Them vao do, cac cong cy Kv nghe Phan mem.voi Sy try giup cua May tinh (CASE - Computer Aided Software'Engineering) da xuat hien de ho try cho nhung no lye phat irlen h'} ‘hong, vk da dtrye sir dyng **$ng rai

W V^ti frrtw W </> f h i r e r t h i l t i+ i& n ht> t if fin O

^ r ■- - - r-'i-s ■- - i " r "&

Vdi viec tang quy me hf thong va dura multimedia vao lie thong, cac to chirc phat trien hi? thong dang phai Strong dau vdi nhung van dc sau:

a Tang khoi luong cong vifc ton dong

So iupng cdng viec ton dpng cua mot to chuc phat trien he thdng da tang len, con so nay cho thay viec phat trien he thong khdng the b5t dau ngay Jap tire theo yeu cau cua ngudi dung Trung binh, moi cdng ty deu ton dQng 2 den 3 nam cdng vi§c.

b S y xuat hifn he thong mutimedia va tang so lugmg cac he thong quy mo ldn

Cac he thdng multimedia trong dd sir dyngh cac du lieu da dang nhu am thanh, video va van ban, da di vao thyc te Them vao do, WAN va LAN da dupe ket hpp vdi nhau v'& nhieu mang ngi bo (intranet) da dupe xay dyng Vi v$y, Vgay

nay ngudi ta phki giii quyet cac he thong cd quy md ngay cang ldn va phuc tap.

Vdi auy md cua cac he thong ngav cang md rong, khoi luong cdng viec bao tri cung tang len Khoi luong nay tang len bdi vi cac yeu cau sua doi he thong tu ngudi dung tang len, viec sua doi cac he thong hien co trd thanh can thiet, va viec sua doi toan bp he thong do gap nhieu ldi cung tang len.

(D Vai trd mat cua to chirc phat trien h i thong

Ben canh nhung cong viec quy udc ve viec phat trien he thong va bao tri, cac to chuc phat trien he thong hien nay dupe trong dpi thyc hien nhung cdng viec cd lien quan nhu sau:

a Ph£t trien he thong cung vdi van hanh va bao tri he thong

Ben canh cac cdng viec quy udc, cac to chu*c phat trien he thong phai chap rihari cdng nghe va phuong phap mdi mpt ckch tich eye.

b Xay dyng vk van h ' nh cac co sd dir lieu va mang

Cac ca sd dir lieu khac nhau la yeu to can thiet ddi vdi viec van hanh va quan ly nghiep vy Ben-canh dd, bay gid khong the xem x£t cac hoat dpng nghiep vy ma khong dung mang Viec xay dyng, van hanh vk quan ly ckc co sd dir lieu va mang nay dupe coi nhu cong vifc thiet yeu cua td chuc ph&t trien he thong.

c Lap ke hoach va dieu phoi tin hpc hoa toan cdng ty

Viec lap ke hoach cho cac he thong ldn bao quat toan bp cdng ty, va phan anh cai nhin cua ngudi dung va ban dieu hanh cong ty, rung la mpt cdng vifc quan trpng cua td chuc.

d Gan chat vdi ngudi dung

NgUdi ta trong dpi rang to chuc phat trien he thong chap nhan cae yeu cau cua ngudi dung mpt cach tich eye va phat trien cac he thdng cd tinh thyc tien hon bao gid het To chuc phat trien he thong cung can san sang cung cap ho tip ky thuat can thiet de hudng dan mdi trudng tinh toan ngudi dung cuoi (EUC), huan luyfn tu xa va huan luyfn tai cho ve

xu ly thong tin trong cdng ty.

1.1.2 Mo hinh phat trien phan mem

Vdi vifc phat trien hf thong, ngudi ta dung nhieu md hinh khac nhau tuy theo quy md cua cong ty va each thuc lain vifc chu dao trong cdng ty (!) day, nhung phuong phap nay dupe md ta mot each van tat Dac biet, chung toi se neu chi liet ve md hinh thac do Uong myc 1.1.3.

X err x e t csisch xiiy n i’3 m ini* ho& tro n g H inh 1.1.3 >?ro c h o c h iV ’g te d e hie*? h o n v e c-*r h th'.Vc H fe ?fi.Ap, cii# vt£c vy!*-'

-do voi khach hang Them vao -do, nguoi chii nha con phai di xin phep cac co quan chinh phu co lien quan.

Dya tren thiet ke so do, ngirtVi xay dung tao ra cac ban thiet

ke chi tiefc co tinh toi nhung rang bu§c can thiet nhu cac dieu kien dja iy va xa hoi cua vj tri nay va gia thanh Cuoi cung, viec thiet ke dupe chia xuong muc cho phep viec xay dyng thyc.

Viec lap rap dugrc thg n\Qc thyc hien tren cac thiet ke.

Vi§c kiem tra dugc tien hanh moi khi hoan tat mQt bQ ph$n Den cuoi, vice kiem tra dugc thyc hien vai sy co mat cua kh£ch h&ng Sau do ngoi nha dugc chuyen giao cho khach hang.

Nhieu lo$i bao tri se dirge tien hanh tuong ung theo yeu cau cua khach

Neu chi rieng b&n ve, khAch hang kh6 co the hinh dung ro rang ve ngoi nha va trong no se ra sao khi dirge hoan tat Do d6, ngudi ta kiem tra voi mo hinh ngoi nh&, ho£c voi cac anh 3 chieu tren may tinh

CAch giai quyet tuorng tu cung dugc dung trong phat trien he thong.

(1 ) Md hinh thac do

Mo hinh th^c do, mQt cong nghe ph&t trien he thong, van la mo hinh dugc sir dung rgng rai nhat Trong mo htph nay cong vi^c dugc phan chia thanh mgt so giai doan, va viec quan ly dugc tien hanh cho timg giai doan.

$Kf&h 1.1.3 h£o hj’tih thdc ifp

Cai ten "thac do" noi len rSng, cong viec dien ra trong mo hinh nay tir thupng luu (lap ke hoach co so) xuong ha luu (kiem thu), khong bao gid di ngupc lai.

(2) Mo hinh ban mau

Mo hinh th^c do co nhung han che sau day:

- Vdi mo hinh thac do, eye ky kho hieu ro yeu cau cua nguoi dung trong giai doan lap ke ho^ch co sd cho he thong Doi khi ngay ca khach hang cung khong bie't duoc nhung yeu cau do.

- Cac bieu dd thiet ke va gi&i thich bang mieng doi khi khong du.

De gi&i quyet nhung h$;i che nay, nguoi ta de xuat ra mo hinh ban mau Vdi mo hinh ban mau, he thong dude xay dyng se dupe lam mo hinh tho vdi cac ngon ngu lap trinh don gian nhu Ngon ngu Truy van cd Cau true (SQL -

Structured Query Language) de giup cho khach hang hieu Sau do, cong viec phat trien he thdng se b3t dau.

BAn mau bao gom nhieu mo hinh da dang.

<Phan 16p theo phuong phip xay dyng>

• "Kieu vut di": Cac manh mau thu bi vut di sau khi da dat tdi myc dich cua chung.

• "Kieu khung xuong"': Cac chi tiet dupe them dan vao cac manh mau thu de md rpng dan no thanh h£ thong du dinh.

<Phan ldp theo muc dp bao quat>

• "Kieu dung bp phan": Mo hinh nay duoc dung trong cac giai doan xac djnh yeu cau va thiet ke ngoai.

• "Kieu dung toan bp": Mo hinh nay dupe xay dung cho tat ca cac giai doan.

Hinh 1.1.4 cho thay mpt vi dy luu do cua mo hinh ban mau theo kieu dung bp phan.

Ngu’cyi dung cho chay ban m iu

O&nh gia , Thiet ke trong |—

Thiet ke ch trinh

I OKL

| V$n hanh v& bao tri J

Vifc dung mo hinh ban mau dem toi cam giac cho nguoi dung cam giac ve sy tham gia cua minh vao cong vifc phat trien hf thong, ngan ngua cac loi trong cac giai do$n thuyng liru von anh huong dang ke tdi cong vifc ve sau.

Tuy nhien, mo hinh ban mau bao gom cac van de sau can duyc giai quyet.

* Chi phi phat trien vuvt qua mo hinh thac do.

• Kho dieu chinh ljch bieu thyc hifn.

(3 ) Mo hinh xoan dc

Trong mo hinh xoan 6c, m§t loat cac tien trinh bao gom thiet ke, lap trinh va kiem thu diryc l$p di lap lai cho tung don

vj co e cua hf thong; vifc phat trien lap lai va nhan len nhieu lan (xem Hinh 1.1.5).

<Cacd$c trtmg>

• CAch dung mo hinh nhy thich hyp cho nhung trudng hyp ma cac dun vj con cua hf thong tuong do! dpc lap

lan nhau.

• Phan nao tuan theo mo hinh thac do.

t Cho phep sir dyng mo hinh ban mau neu can.

• Duqc sir d y n g trong kieu phat trien huong doi tuong va cac kieu khac

(4 ) Phat trien huting do! turgng

Gan day, ngudi ta chu y den cach ph£t trien huong doi tupng rrheo me hinh nay, h f thong dupe xet nhu* mpt tap hpp cac doi tupng, va vifc phit trien dupe tien hanh tren co s6 doi tupng Trong ph£t trien doi tupng, quy trinh tir phan tich den thiet ke den thyc hifn dupe tien hanh l|p di lap lai, tao nen mpt loai mo hinh xoSn oc.

(5 ) Cau true Phan tach Cong viec

B £ dat toi myc dich cua minh, mot dy an phat trien hf thong dupe phan taeh thanh cac m uc theo thu ty sau, tuy theo tien trinh phat trien.

1 Muc quyet djnh cau true chinh cua dy an

2 Muc cong vifc tao nen khuon kho cho tung giai doan

3 Muc cong vie- hifn hanh chi tiet

Tu ket qua phan t&ch cac muc, nguoi ta bo sung them die myc dich cu the, ljch cong vifc, va vifc quan ly cieh tr'mh (cac chi tiet cua muc dupe x&c djnh b6i vifc quan ly n&y cang mjn cang tot), de thu dupe Cau true Phan tach C6ng vifc (WBS - Work Breakdown Structure) WBS dupe bieu dien bing cau true phan cap nhu dupe ve trong H inhl.l 6.

u u an phcii tr»in san j

Vi|c dung WBS cd nhung ich loi sau:

• Co dupe iroe lupng chi phi va du lieu cho viec phan tich chi phi.

• Lam sang to cau true cong viec va bao qua! cong viec cua mpt dy an, cung vdi tr^ch nhiem ve cong viec.

• Nam dupe tien dp hien t«*i cho tung don vj cong viec, va l|p ke ho^ch cong viec dupe de dang hem.

• Ten cua cac don vj cong viec da phan taeh va ten cua he thong phan lop la mpt phan cua bi quyet chuyen gia.

Voi WBS, myc dich cua cong viec, nhu chat lupng, chi phi va thoi gian, dupe cho tren co sd don vj cong viec Cho nen, die n.yc tieu dong vai trd tham chieu cho cong viec dupe thuc hien.

(6 ) Tien trinh va Mo hinh Tien trinh

Tien Tinh dupe djnh nghia 1& t|p hpp c£c don vj cong viec (vi dy nhu phan tich, thiet ke v& che t$o) can thiet trong viec I90 n s&n pham (ke c& sin pham phan mem), dupe sip xep theo chuoi thoi gian Moi cau phan cua tien trinh dupe gpi

la "gai do$n tien trinh" Vdi WBS mo ta d tren, cong viec dupe bieu dien theo cap b$c, nhung khong theo chuoi thdi gian.Su khiic biet ldn la d day.

Tien rinh dupe thiet ke so bp trong giai doan l|p ke hoach co sd Trong ban thiet ke nay, mo hinh tien trinh dupe neu tron^Hmh 1.1.7 cd the dupe dung de tham khao.

Hinh 1.7 Md hinh tien trinh

Thi^t k6 Ch6 tao x&y dt/ng v& ki&m thu- Chuyen

dich

V£n h^nh v£ boio tri

MS hoa Kiern Ihu1

Chuyen djch

Bao tri

chu'ortg trinh

Sinh chirong : trinh

KiAm thu'

• ChuyAn djch

- i i B3C iri |

ThiAt kA ngudi

ThiAt kA trcng

Thi/c hi§n phat triAn KiAm thi>

h$ thAng

Bio tri

1

ThiAt kA module

M3

ho ci

KiArr.

thtp den vj

KiAm thu* m6c iiAi

ChuyAn dich

ThiAt kA h£ thAng d?i cu*ong

ThiAt kA h$ thAng chi tiAt

ChA tao KiAm thu*, chuyAn dich V$n hinh

TtwAt kA giao di£n ngu’iri dunp

TtiiAt

kA cAu true he thAng

ThiAt

kA cAu true chuong trinh

Up trinh

KiAm thir chuang trinh

KiAm thu*

m6g nAi

KiAm j thiV h$

Cac san pham phan mem dupe tao ra qua tung tien trinh phat trien Do do, bin thiet ke cua tung tien trinh, tu do tao nen co so cua tien trmh, se co anh huong Ion toi chat lupng va chi phi cua sin pham phan mem.

1.1.3 Vong ddi phun mem

Vong d6i la tien trinh tu khi sinh den khi diet, hay khoang song cua mpt vat song hoac mpt san pham Vai khai niem

ve v6ng ddi phan mem (SLC) cung vay, khoang thai gian tu thai diem b3t dau d y an phat trien h$ thong cho den th6 i diem vi£c cap nhat he thong ket thuc dupe xem nhu cupc doi cua he thong Vay, cac hoat dpng dien ra trong thai ky do (dirp»c bieu dien theo kieu cupc song thtfc) dupe dung lam mo hinh dien tA cho moi quan h£ giua cac tien trinh.

Hinh 1.1.8 Vong ddi cua h f thong phan mem

Chuyen sa n g

rncyi

Vong doi cua he phan memTrong phan sau day se giai thfch ve mo hinh thac do, la mo hinh dien hinh nhat.

( 1 ) O ac truYsg ciia mo hinh th a c do

Hinh 1.1.9 bieu dien mpt hinh anh toan the cua mo hinh thac do.

Hinh 1.1$ Binh anh toan the cua mo hinh thac itu&c (cau true hinh chu V)

f L$p ke hoach cu1 so R j ] Van h6nh/bao tri j

j Phan tich _ JR j [ Kiem ihfr v$?; hanh

Trong mo hinh thac do, cac ky thuat dircri day dugc sir dyng Vi v§y, co the true qaan hoa mo hinh nay theo cau true hinh chu* V trong Hinh 1.1.9.

• Tir giai doan l§p ke hoach co s6 tai giai doan l$p trinh: phuorng phap l£m xnjn timg buoc (tiep can tren xutfng).

• Tir giai doan kiem thu don vj toi giai doan kiem thu vgn hanh: phuong phap tich hgp timg bixac (cach ciep

c$n dirori len).

Cac d$c trung cua Mo hinh thac do dupe tom tat sau day:

<Cac d£c trung>

• Cong vi§c ph&t trien h£ thong dugc chia thanh mot so giai do$n de quan ly.

• Khi cong vifc cua mpt giai doan ho&n tat thi san pham cua cong vi£c (ke ca cac !o$i thi li£u thiet ke) cua giai

doan nay dirge xet duy£t de kiem tra tinh dung din.

• Cac san pham cong vi§c (ke ca du lo^i tai li£u thiet ke) tir giai do?n n&y dugc chuyen tiep sang tien irinh ti£p theo, trong tien trinh do cong vi«?e dugc thyc hien v6i sAn pham vua nh|n dugc Theo cach nay, s\jt nhat quan

trong vi£c phat tiien h| thong dugc duy tri.

• Ve co b&n, khong dugc phep tro l$i cong viec cua giai doan trudc.

• Cach to chuc dy an co tam quan trpng chu chot

Nhu da mo t£ 6 tren, vi£c phan chia tien trinh phat trien he thong th&nh mpt so giai doan de quin ly la mgt lrong nhung die trung cua md hinh thac do Hinh 1.1.10 minh ho? moi quan h§ giua tung giai do?n vh khoi lupng cong vi£c

6 d 6

Trong cac myc (2) toi (8) duoi day, se mo ta dai cuong timg giai doan cong viec trong phat trien h£ thong.

Hinh 1.1.10 M oi yuan h$ xtica Ittrig giai itoau trong md hinh thdc (to va kh oi hrpng cdng vi$c cua no

(2 ) Lap ke hoach cd sd

L4p ke hoach co s6 la buoc dau tien cua viec phat trien he thong Can ph&i co hieu biet thau dao ve cac hoat d§ng tin hoc hoa dang co, neu khong, se khong the n&o phat trien dupe he thong co the thoi inan cho ngudi dung Do v$y, l$p k§'ho$ch co sd b it dau bSng viec phan tfch he thong dang c6, roi x ic djnh ro van de cua n6.

Hinh 1.1 J 1 L$p kehoQ ch c o $ d

Thu tyc chi tiet trong lap ke hoach co s6 du<?c mo ta nhu sau:

(D Ke hoach h? thong hod

Lap ke hoach he thong hoa la cong viec soan thao ra cac ke hoach co so cho mpt he thong.

<Nhiem vy>

• Dieu tra va phan tich cac van de trong cac hoat dong co muc dich he thong hoa.

• Dua tren ket qua ciia muc a, khao sat giai phap tot nhat va xem xet iai sir can thiet nhat trien he thong Neu sau

khi khao sat va xem xet, U»i thay rSng co mot giai phap tot horn, thi chap nhan giai phap tot han.

Neu tu cong viec cua muc b thay rang vi^c phat trien he thong jvioj la thich hyp, thi !$p han ke ho^ch he thon^ hoa va de tnnh cho nguoi to trach nhu/iu.

• Dy- an dupe to chuc (ke ca bd nhi^rn ngudi phy trach)

* Ban ke hoach tai nguyen he thdng (udc lupng) dupe soan thao.

o Ke ho^ch nhan sy

o Phan cung cho phat trien h£ thong

o U ac 1irj!t.c quy rod phat trien (ke ra nhan luc va ngan sach)

o Tai chinh

V a nhung thu khac

• Ban ke hoach tien trinh cong vi£c va ljch bieu muc cao nhat dupe soan ra.

Cocac kieu lich sau:

o Ljch bieu muc cao nhat : Ljch cho toan bp h£ thong

o l,jch bieu mire trung : Ljch cho tung giai do$n trong vi£c phat trien h£ thong.

o Ljch bieu mire thap nhat ; Ljch bieu cho tung ngudi cd lien quan.

Neu lap dupe tat ca cac loai ljch bieu tren tai giai doan nay \k tot nhat nhung thuc te thi kho lam dupe Cho

nen it nhat can soan ra ljch bieu muc cao nhat tai giai doan nay.

<Tai ii<?u>

• Bin k6‘ hoach phit trien.

Trong xac dnh yeu cau, cac chuc nang can dat dirpc tieu tao nen dau vao cho vifc phat trien h£ thong, va cong vi£c phan tich vi djnh nghia cac yeu cau doi vdi he thong thdng tin dupe lam chi tiet hon so vdi cac ban ke hoach phat trien,

bang cac pluong phap cd cau true nhu DFD (Bieu do Luong Du li£u) va ERD (Bieu do Thyc the Quan h§)

• Ban d£c ta yeu cau

(§) Tam tat vi'vi$c Jap ke hoach cu t;a

Vi£c lap kehcach ca sd la giai doan thiet Ice ra dai cuang ve h $ thong tin, ke ca vi|c phsir tfch h§ thong can phat trien va

vach ta ijch bieu muc cao nhat Ket qua cua no anh huong rat nhieu tdi cac tien trinh sau dd Ngoai ra, day la giai doan dau tien trong vi£c phat trien he thong Do do, dieu can thiet la cong viec phai dupe thyc hien vdi sy xac nh$n cua ngudi dimg, cong v iecd u p c ngudi phan tich h§ thong co ky n&ng cao va cd tri thuc cot loi thyc hifn.

(3) Thiet ke ngoai

Thiet ke ngoai la thiet ke cho phan thay dupe ben ngoai, hay nhung phan danh cho giao tiep vdi ngudi dung Do do, he thong dupe thiet ke thuan tuy theo quan diem cua ngudi dung khong de y tdi nhung rang bu$c ve phan cung (nhu may tinh) Ben c?nh do, cung phai lam sang td cau tnjc h£ thong can cd de dat tdi duoc thiet ke do.

Hinh 1.1.12 Thiet k e n g o a i

<Nhiem vy>

• Kiem tra d$c tA yeu cau

Sau khi kiem tra ban dac ta yeu cau co trong bAn ke hoach co sd, thi vi£c xet tong quan ve he thong dupe bieu dien

bdi vi?c dung cac bieu do sao cho viec xir ly va luong du lieu cd the duoc hieu de dang Dya tren cac bieu dien nay, thyc hi|n viec phan chia h? thong thanh cac he con va thiet ke vao/ra Cac DFD hay HIPO dupe dung de ve bieu do,

• Xac djnh cac he con va phan d u a tiep

Toan bp he thong duoc chia thanh mpt so he con tien co sd chuc nang, roi he con lai dupe phan chia tiep thanh cac don vi nhd hem.

• Thiet ke tai lieu va man hinh.

Trong thiet ke man hinh va tai lieu, cac thie't ke phae thao cho man hinh va viec chuyen doi man hinh, thiet kephac thao cho tai lieu vao/ra se dupe tao ra (Cac cong viec chi tiet de thyc hien thiet ke nay se dupe tien hanh khi lam thiet ke trong.)

• Thiet ke ma

( j dciy, vi^c chic't ina, rinv" vI qc dmh He thong ma, ss dupe tien hanh

• Thiel ko dir Is6u logic

Trong thiet ke du lieu logic, mol quan lie giua du lieu duoc phan tich, va rut ra ung cu vien cho cu so dir liyu va *vi> (C ar r:6og \'»p* chi iiel: de thuc hifn duyc tien hanh khi iarn tiiiet ke trong).

• Xet duyet thiet ke ngoai

Tai li£u thiet ke ngoai dupe xet duyet.

<T&i lipu>

• Tai ii£u thiet ke ngoai

® Bao cao x£t.duy§t tai li£u thiet ke ngoai

Trong thiet ke trong, cac cong vifc minh ho? trong Hinh 1.1.13 se dupe thyc hifn.

Hinh 1.1.13 Thiet ke trong

<Nhifm vy>

• Phan hoach va cau true chuc n&ng (thiet ke cau true)

Trong phan hoach va cau true chuc nang (thiet ke cau true), rndi h f con deu phan hoach thanh cac don vi lap trinh,

va luong du lifu va xu ly giua cac chuong trinh dupe lam sang to.

« Thiet ke du lifu vat H

Trong thiet ke dir lieu vat ly (thiet ke tep), de dung hieu qua cac dac irirn^ phan cung, vifc thiet ke v$t ly ve tfp va

co so du* lifu dupe dya tren thiet ke’du lieu logic da duyc ihyc hien trung giai doan phan tich he thong.

Thiet ke vao-ra chi tiet

TVivrttr Vp' v » o ra chi Her car chi Het ve m in hinh va tai lieu vao ra duoc iiiiet ke bang vifc dun& mau difc bift.

• Xet d uy f 11h «et ke Iron#

Vifc xet duyft duoc tien hanh voi tai lifu thiet ke trong.

<Tai lif u>

« Tai lifu thiet ke trong

• Bao cao xet duyft thiet ke trong

(5 ) Thiet ke chuttng trinh

Trong giai doan thiet ke chuong trinh, cac cau true trong ciia lung chuong trinh se duyrc thiet ke Moi chuong trinh da xuat hien qua vifc phan chia 6 giai doan thiel ke trong lai du<?c phan chia tiep m$t each co phan cap thinh cac don vj

chuc nang du<?c ggi la module Sau do, den lu<?t cac giao difn (du lifu vao/ra) giua cac module duy*c thiet ke.

Ngoai ra, trong giai doan nay cung chuan bi cac ke hoach cho vifc kiem thu chuong trinh (kiem thu tich hypi va thiet iap cat tru in g hop fcien’i tim Xem minh ho* ve cac cong vifc du^c tier, hin h trong I Tinh 1.1.1.

H inh 1.1.14 Thiet ke chuong trinh

<Nhifm vy>

• Thiet ke c6 cau true cho chuong trinh (Phan hoach module)

Trong thiet ke co cau true, moi chuong trinh lai duoc phan hoach thanh cac don vi chuc nang duoc goi la module de cho ph£p de ding bio tri, ec>n lu6ng du lifu vi xvr ly giua c ic chuong trinh thi ro ring, m^ch l^c Ben canh d6, cac chuc ning cua timg module v i giao difn giua cic module cung duyc x ic djnh.

o T}iiet ke cac trudng hop kiem thu chuong trinh (kiem thu tich hop)

Chuan bj cac ke hoach cho kiem thu chuong trinh, va thiet ke cic truong hop kiem thu.

• Xet duyft thiet kechirong trinh

Trong xet duyft thiet kechuong trinh, tien hanh xet duyft tai lifu thiet ke chuong trinh.

<Tai lifu>

• lai lifu thiet ke chuong trinh

« ij-io cao xet duyft ihiet ke chuong trinh

( 6 ) Lap trin h

Trong giai doan lap trinh, se thuc hi$n viec thiet kc cac cau true logic cua module da djnh nghla irong giai doan thiet ke chi tiet, va viift ma chirOTig trinh cho cac module Ben canh do, cune chuan hi cac ke hosch cho kiem thu module (kiem thi? don v j), va thiet I§p cac (ru'Oiig hyp kiem thir.

• L^p ke ho$ch kiem thir don v j;

Cac ke ho?ch kiem thir don vj duoc chuan bj (T$o ra dir lieu kiem thir thich hop, xac djnh Ijch kiem thir.)

• Ma hoa

Tung module duQcma hoa trong ngon ngu* lip trinh

• Kiem thir don vj

Tien hanh kiem thir dun vj cho tirng module

<Tcti lj?u>

• Tai lieu thiet ke module

• Bao cao xet duy^t thiet ke module

• Keho^ch kiem thir dor\ vj

® Danh sach chuong trinh goc

® Bao cao xet duy?t chi rong trinh goc

• Bao cao kiem thir dan vj

( 7 ) Kiem thu*

L.dng dec kiem thir duoc tien hanh-de pirat hi^n 16i tiuitg hanlv vi 'va caii tiuc cua module, chucmg trinh hay he t)i voi hr cavh lh mot tong the (xem rh rh 1 i.16) Neu ioi duvc tim :v thi car, lam phan hci, nc-u car., va chuyer den

doar* lao trinh hav eiai doan thiet ke de sua chua Sau d6, lai lien h&nh kiem thu de kiem tra lieu 16i da diroc * * i ^ v» ' sira hay

d iu a

Hinh h i 16 Cac b a i ki/m thu

<Nhi?m vu>

• Kiem thu don vi (duoc tien hanh trong giai do$n lap trinh)

Trong kiem thu don vi, moi module deu duoc kiem tra xem li£u nd co dupe thyc hifn dung hay khong.

• Kiem thu tich hop

Trong kiem thu* tich hpp, cac kiem thu dupe tien hanh cho tung chuong trinh d u p ctao ra b§ng v i l i e n ket cac module Viec v$n hanh cua chuong trinh v& giao di£n giua ckc module cung dupe kiem tra.

• Kiem thu he thong

Irong kiem thu he thong, sy v§n hanh cua he thong vdi tu cach la mpt tong the dupe kiem tra toan bp theo quan diem cua muc dich va hi<?u n5ng can co Sau do, vi£c b£t dau van hanh thuc te dupe quyet djnh dya trdn ket qua n&y.

• Kiem thu v£n hknh

Trong kiem thu van hanh, c&c nh6m van h*mh tu phia ngudi dung tien hanh cac kiem thu trong dieu kien va moi

trudng gidng nhu trong v§n h&nh thuc te.

<T&i li£u>

Bao cao kiem thu dem vj

Bao cao kiem thu rich hpp

Bao cao kiem thu he thong

Bao cao kiem thu van harih

Van hanh va bao tri

He thdng da dupe dua vao boat dpng Cat: hoat dpng bao tri dupe tien hanh khi phai: hien thay khiem khuyet (vi du: kh6 dung) hoac loi, hoac khi thay khong the tranh khoi thay doi trong he thong Irong mpt so trudng hpp, h£ thong can phai dupe sua doi.

1 »-» i r I ^ .wfrir^ *»>« -« »»m» »»**_*.* f 1 fit TZXisyi't

He thong thong tin d u g c phat triers tren co sd xay dirng theo dan dac hang Dua tren yen can cua ngudi dung, ngudi

phai trien phan tich cic chuc nang can d<?t dupe, thiei ke lap birth, va Rilm thu h§ thong tiuoc khi hoan thanh vifc phai uicn hf it tong oau uo ugu'ui uuitg uiuc i'iivA cOi'ig vice vua iftiiih bfiiiji cach su ui,»f«g hv thon^ da dupe xay d\?ng theo cac yeu cau rieng ciia hy.

Tuy nhien ngay nay nhieu cong ty g2p trd ngai bdi cdn ton dong nhieu cong vifc chua lam dupe (luc la cac dau muc cong vi£e van chua dupe bat da'u) San xuat dua theo dan dat hang la nguyen nhan lam tang them so cong vifc ton dpng Vai each san xuat nay, vifc phat trien hf thong phai mat nhieu thang va nhieu n£m Ngoai ra, de phat trien hf thong, can phai co sy tham dvr cua cac chuyen gia nhu ky su hf thong (SE - System Engineer) The nhung, trong thyc te nhieu no lv,rc cua cac ky su hf thong lai tieu ton vao cong vifc bao tri cac hf thong hifn cd, nghia la so' nhan vien cdn lai cho cac du an mdi it di Tmh trang nay da tao ra y luong ve vifc dung lai phan mem hifn cd.

Khi dung lai phan mem, cac bp phan hoac toan bp phan mem dupe dung de tao ra phan mem mdi, ho^c phan mem hifn tai dupe phan tich va sua doi de thu dupe phan mem mdi Theo cach dd, mpt phan mem cd the dupe dung nhieu lan trong cac h f thong khac nhau.

Cd nhursg cach sau day de dung lai phan mem:

• l>iing lai nhu cac cau phan

• Dung lai qua tai ky nghf

(1) Dung l$i nhu' cac cau phan

Phuong phap tao ra cac cau phan tir phan mem hifn cd va lap rap chung de xay dung hf thong mdi cho phep giam dupe chi phi va t5ng chat lupng cua hf thdng Ben canh dd, chu ky phat trien cd the ngan lai- : *■

(D PHuotig phap de tao ra cac cau phan

Cac bp phan ciia phan mem duoc chinh ngudi dung tao ra, hoac dupe ngudi ban phan mem cung cap- Cac bp:ph#n do ngudi ban phan mem cung cap deu dupe chuan hoa Tuy nhien, vifc chuan hoa theo djnh dang ky thuat va cich bieu dien cur*; can thiet doi vdi cac bp phan phan mem do ngudi dung t$o ra; ly do la d cho cac cau phan khong chuan hoa

thi khonj the lap rap dung vdi nhau Hon nua, xn$c dii (ve co bin) su dyng ngon ngu nao cung dupe, nhung tot hon ck

la nen dung cung mpt ngon ngu de de phong trudng hpp phai sun ma ngudn.

Hinh 1.1.77 Chuan hod cac cau phan

/

| c ^u I C&c bp ph$n, co ccic chuang trinh nauori dupe cung cip.

i piiAn ! c6 th£ dupe chuyen bift hoa (sua doi), d& diing theo c£ch

diing dan hon,

i'n* vi$n can phan va hr thong tim kiem

De xay tirng he thong bing vice cd«_ cau plum phan metn, cac «.au plian duvc luu giu va >Juv ti; trung, Ihu vien

cau phan So cac cau phan dugc luu giu trong thu vien cang Ion, thi ket cau cua he thong cang tro nen linh hoat hon.

Horn nira, khi h? thdng tim kiem dupe cai tien, thi thu v $n cau phan se duoc dung thucmg xuyer hem, cai tien ca so du

li§u can phan va tAng co h$i dung thu vien

Hinh i.t W Thu w in cau phan

(3) Cai tien cac cau phdn - tao ra cong cu va cdng cu tim kiem cau phdn

Khi cau phan phan mem dupe tao ra va co mpt cach thuc de d&ng de tim kiem cau phan trong thu vien, thi se tang toe dupe viec dung lai phan mem, boi vi de dung He qua la se co the c6 dupe cac cong eg tao cau phan v& nhung cong cy tim kiem cau phan tot hon.

Cac phuong phap hay cong cy de phat trien ung dyng bling viec \&p rap cac cau phan phan mem dupe tao ra, dya tren

cac d|c ta chuan de c6 kha nang dung lai, dupe gpi la "componentware."

(2 ) Dung l?i qua t&i ky ngh$

Viec tao ra phan mem moi tu phan mem hien c6 dupe gpi la "tai ky nghe." T&i ky nghe la cong nghe dupe dung de tao

ra he thong mdi bSng viec t|n dung he thong dang dupe su dyng.

De thuc hien tai ky nghe, nguoi ta thudng dung cdc cong cy CASE (nhu cong cy CASE bAo tri).

Hinh 1.1.19 Tdi ky nghe

c -4>

Tronc tai ky n-'hO thor.g thuang, hutac dau tien la rut ra cac die la cua phan mem hien co Cong nghe dugc dung trong

phan c 6r*g vi^c nay dugc goi Ik "ky ngh«l dao" Sau do, due ta cho phan mem moi duvc iao ra bSiift cach sura doi cac d*k* t£ da rut ra Dua Iren cac d$c ia moi, mot h| thong moi sc duoc tac ra Cong nghf phat trien truyen thong dirge dung 6 day dirge goi ia "ky ngh£ tieh", (irottg, phan voi "ky ngh£ dao" (xem I ('mb 1.1 10).

1.2 Phan tich yeu cau va phuong phap thiet ke

Sau khi ban ke ho$ch thyc hien d y an phat trien rnQt sin pham da dirge ianh dao cong ty ho&c nguoi dung chap thuan, thi dieu dau tien can dug*c tien hanh trong di^ an phat trien la phan tich cac yeu cau Diroi day se trinh bay ve cac phirong phap phan tich va thiet ke dien hinh.

1.2 .1 Phuang phap lap bieu do

Trong phan tich yeu cau, cac chuc nang cua h$ thong ung dung can co duyc rut ra bing cach t$o nen mQt mo hinh dai

cirong ve he thong, de xay dyng ra san pham Trong m yc nay se mo t i cac phuong ti§n giup cho cong v i£c phan tich,

nhu bieu do DFD, bieu do ERD, bieu do chuyen trang thai va UML.

(1 ) DFD (Bi£u do Luong Du* li$u)

Bieu do Luong Du li§u (DFD) la phuong phap phan tich M r.g cach ve bieu do, vk bieu dien cac tier, trir.h nghiep vy

m^t cach tryc quan de tr<? giup hieu Met ve he thong, bing cach chu y den luong d u lieu.

Hinh 1.2.1 Bieu do Luong DQ li$u (DFD)

(mui ten co ten)

Chi ra luong du lieu

Chi ra xu H/ chuyen doi du lieu

Kho du li?u (Hai du6ng song song)

Chi ra kho du lieu

Tac nhan ngoai (hinh vuong)

Chi ra nguon hay noi nhan du lieu (thuong

la nguoi hay to chuc ngoai viec phan tich)

DO li$U 3

M0t hinh anh ve DFD

( 2 ) E ftD (B le u cfo T h u c t h e Q u an h | )

BieVi d o Thvrc the Quan he (£Rl>) diru ra mpt rno hinh dir lieu trong <16 h§ thong myc tieu duoc bieu dien bang hai khai

"th yc ihe," va "quan h§" giirU car fhue the ERD cung e&n duoc gpi ta ' mo hinh v|n huiii; ughiep vu" vi no dupe dur*g d e tao ra mo binh v§n hanh nghi? p vu.

H hih 1,2.2 Bi&’u do Thuc iheQ uun h?

ERD b<ao gom ba phan tu sau:

• T h y c the: Bieu thi mpt thyc the nh^m si> dyng cho quan ly; duoc bieu dien bang hinh chu nhat.

» Quan h i: Bieu thj moi quan h£ giua cac thyc the, va ca moi quan he giua thyc the va quan he, duoc bieu dien

bang hinh thoi.

• Thupc tinh: Bieu thj cac d$c trung va tinh chat cua thuc the hay quan he, dupe bieu dien blng hinh ellipse.

ERD trong Hinh 1.2.2 cho thay:

• Cac thuc the "Giao vien" va "Hpc vien" dupenoi qua quan h £co ten "Bai giang."

• Thyc the "Gi&o vien" co thupc tinh "Ten gi&o vien."

• Thvrc the "Hpc vien" co thupc tinh "Ten" va "Phieu ghi."

• Quan hf "Bai giang" co thupc tinh "Ten chu de."

Co ba kieu quan he: "1 - 1," "1 - N " va "N - N" v6 i N la so nguyen Ion hon 1 Trong thi du nay, neu giao vien dpc bai giang cho nhi£u hpc vien va hpc vien d y nhieu bai giAng khac nhau do mpt giao vien gi&ng, thi moi quan he la N-N.

(3 ) Bieu do Chuyen Tr$ng th&i

Bieu do Chuyen Tr^ng thii dupe dung de so do ho£ nhung tinh huong c6 tr$ng thAi bien thien theo th6i gian vA hanh

vi Bieu do chuyen tr^ng thai tren Hinh 1.2.3 minh ho$ cAch cac man hinh thay doi boi cac thao tac dupe thyc hien tuong ung v6i tung man hinh, chang han nhu nhap du* lieu va nhan phim chuc nAng.

Hinh 1.23

(4 ) UML (ttg o n ngSr ;r.c hinh hoa th o n g n h a t)

UML ia ngon ngu mo hinh hoa d ugc dung trong phan tich htrong doi tugrtg Da co nhieu phuong phap bieu dien, rnoi

phuong phap lai tuy thugc vao nguoi de xuat ma khong rhong nhat vai nhau UML duyc phat minh rfe chuan hoa chung.

Hinh 12.4

- Bieu <36 16p

a 3 K

Huy bd / b&o tra lai xu

<33 dua vio

Hinh 1.2.4 UML

1.2.2 Lap bieu do phan tkh/th iet ke

Cac chuc nang he thong da x&c djnh trong cac tien trinh thugmg luu dupe thi/c hien bang mot so chuang trinh Luu do

la phuong ph^p lap bieu do tieu bieu nhat dupe dung de phan tich cac cau Uuc logic Trong myc n&y, luu do, cac so do c6 cau true va bAng quyet dinh du<?c mo ta voi tu cach la cdc phuong phap lap bieu do trong phan tich va thiet ke.

(1 ) Lu*u do

Dua tren vi?c xac djnh/phan tich cac van de phuc tap, thu tuc xtr ly, va pham vi cong viec, luu do \k mot trong cac

phuong phap (va la phuong phap tieu bieu nhat) dung de bieu dien cach thuc giai quyet chung va bieu dien luong thao tac can thiet, being c ic ky hieu thong nhat.

Hinh 1.2.5 li£t ke c ic ky hieu du<?c dung trong *.uu do, duoc dinh nghla trong chuan JIS X 0121.

Htnh 1.2.5 Cac fcy hi$u dupe dung trong luu do

Du li£u Chi ra du* lieu ma vai no phuong tien khong duoc xac djnh.

Du lieu duoc cat Chi ra dir lieu duyc giu theo djnh dang thich hgp cho xu ly (phuong ti(?n

Bo nho trong Chi ra du lieu duoc cat giir trong phuong ti£n bo nha trong.

r \ B() nha truy nhap Chi ra du lieu truy nhap duoc theo cach tuan ty, nhu tren bang hr va

tuan tu bang cassette.

' f \ Bp nha truy nhap Chi ra dir lieu co the truy nhap tryc tiep, n h u dir lieu tren dia tu va dia

j - - ;

j lai lieu Chi ra du neu tren phirong tien con nguoi co the doc dupe.

Chi fa dir lieu Iren bat ky phuong tien nao duoc dua vao bang cac

! Cai vao thu cong phirong thuc thu cdng, nhu ban phtm true tuyen chuyen m§dh, nut bam

j

f '\ , * , Chi ra dfr lieu tren bat kv phuone tien nao cho ohen hien thi thonj? tin

\ - / con nguoi dung, nhu tren man hinh hien thj hay bp chi bao tryc tuyen.

| J Tien trinh Chi ra bat ky kieu chuc nang xir ly nao.

71 Tien trinh dinh Chi ra tien trinh bao gom mpl hay nhieu thao tac hay lenh duoc xac

1] truoc djnh, chang han, mQt trinh con.

Thao tac thu cong Chi ra bat ky thao tac nao duoc giai quyet thu cong.

O Chi ra viec thay doi cua mQt lenh hay nhom lenh, giong nhu vifc thiet

Chuan bj l£p chuyen mach hay thiet lap ban da'u cho mQt trinh, ma anh huong toi cac than ta^ sau

Chi ra mQt chuc nang quyet djnh ma voi mQt cong vao va cac cong ra,

^ , chi mQt trong chung c6 the dupe ly a tai mQt thdi diem , viec ly a mQt cong

ra tuy tnuQC vao ket qua cua viec tinh dieu kien duQc m o ta trong kyhieu

/ -\ , Bao gom hai phan; phan dieu kien cho viec ket thuc va ten chu trinh

L j G iai han chu , , f > x ^

I -1 , d uoc viet trong ky hieu chi ra cho bat dau va ket thuc cua chu tn n h

tuong ung.

Ducmg Chi ra luong dir lieu hay dieu khien.

^ „ , , Chi ra mQt cong dua ra toi mQt cho k hac tren luu do hay rnQt cong dua

Thiet bj dau cuoi Chi ra mQt cong dua ra, hay mQt cong dua vao tu* moi truong ngoai.

Duqc dung de them loi gidi thich hay luu y de lam sang t6

E lip D uqc d u n g th ay ch o ky hieu d u o n g , v a chi ra ran g mQt ky hieu hay

n hom ky hieu bi b 6 qua.

*JIS X0121

Luu 16 bio gom hai kieu sau:

« l m do he thong (so do tien trinh)

♦ I ru d o di iron g trinh

© Liu tid h? thdng (so do tien trinh)

H inh ? 7 fi V4 rlu l»ni /tn h$ th n tia

- — r " ‘ - " 6

I DO* ii$u uuc iugng

dugc dua vao

'v

Ofr Ii0u u t e Iugng

dugc kttm tra

DO !i$u w&c Iugng

dirge ki&m tra

S5p x6p d& ti$u i/&c

Ban k& chi ti£t dugc B£o c£o thing dugc T$p luang nSm dugc

T$p luang nSm (mdi)

<2> Luu do chuong trinh

Khi chuong trinh dugc phdt trien, thi lira do chirong trinh dirpc dung de mo td cho cdc thu tyc xir ly dyatnen ket qua phan tich b3ng luu do.

Dong ban k6 chi tilt vung in ra

mo ta dya tren djnh ly cau true (xem muc 1.3.3) co the sir dyng dupe.

C ic sa do c6 cau true bao gom c ic kieu khic nhau sau day:

*Cau true tuan iyr>

|

I

t

<c4u true tuyen ehon> I

*ccau iriic lap (Kiiu Do While)> iruc lap

(Kiiu Repeat Until)>

L

i KiV $ i

<Cau true CASt>

(2) PAD (Problem Analysis Diagram - Bieu do phan tich van de)

PAD mo ta cho cau true logic cua thu|t toan biing cau true cay.

Hinh 1-2-8 V f dy

ve s?n j?o fIS

Hinh 1-2-9 V i dg v& PAD

(3) SPD (Structured Programming Diagram) Bieu do lap trinh co cau trite

SPD mo ta cau true logic cua thujit toan bang so do cay co cau true.

<Cau true l£p (kieu Do W hiie)> <Cau true I3p (ki£u Repeat Until)>

W H IL E : Oi£u ki§n \ n U N T IL : Di&u kien

Xi> If 1 Xu* li 1

4 HCP (So do mo ta gpn va co thu1 b$c - Hierarchical and Compact description chart)

HCP m o theo cung cach nhu SPD, cau true logic cua thuat toan bing so do cau true cay.

5 YAC [I (Vet Another Control chart II So do dieu khien khac if)

YAC IJ cung mo ta cau true logic cua thuat loan co so do co cau trin

Hinh 1-2-12 Vidy ve YAC 11

<C3u true tuan iy>

C ic dieu kien can duyc kiem tra cho nhung van de xuat

hien duyc lim thanh dang cau h6i

0 dieu kien Tri loi cho cau h6i tir mpt cuong dieu kien dupe

mo ta bing Y (c6) hay N (khong)

Tat ca nhung hanh dong co the duoc tien hanh cho van

de da dupe xac djnh trong cuong dieu kien dupe mo ta

ro rang

Thay vi Y hay N cho o dieu kien, X dupe vie't chi khi hinh dpng dupe tien hanh

i

Hinh 1.2.13 Bang quyet djnh

7 2.3 P h u rrn r nhan th iet ke ; i

( 1 ) Pb& rt t ? c h v a t h i e t k e r a a n * t r £ c

Phuong phap cd cau iruc la mgt thu^t rg ir to hgp ca phan tich co cau true va thiet ke co cau true Voi phan tich co cau

t m t (S A ), c a c y e n rau ve h e lh o n g dfch c a n p h at in e rt dugc phan lich bang v i? c ch u y uyc bi$t toi chuc n an g cu a hv thong, va luong dir lieu giua cac chuc nang Phuong phap phan tich nay dung ba tai lieu sau bieu dien ve mat so do cho the giai nghiep vu ur.g dung vai luong d u lieu cho phan tich.

Bieu do ; Cho phep mo ta theo-phan cap, tao kha nang phan chia phan cap ve cac chuc

luong du li$u (DM3) nang he thong.

Tu dien du* : Dugc dung de dinh n&iim cat cau true du lieu cua nhung du- lieu co ten dugc

D^c ta mini : Vi£c phan chia co phan cap tiep tuc cho cac chuc n&ng dan toi cac thao I ac co

sd Nhung thao tac co so nay dugc djnh ngiua trong dac t£ mini.

Phan tich co cau true nguyen thuy chi ngu y cho viec mo ta du lieu va tien trinh bang bieu do Tuy nhien De Marco da

bo sung them viec dung tu dien du lieu va dac ta mini vao phuong phap nguyen thuy Ket qua la vi£c phan tich co cau true bay gid da dugc dung nhu mgt phuong ph&p lu§n.

Muc dich cua phuong phap thiet ke co cau true (SD) la de chuyen cac tien trinh trong DFD dugc sinh ra bdi phan tich

co cau true thanh cac module chuong trinh, va tien hanh phan chia thanh cac module bang cach tiep can tren xuong Phuong phap phan chia STS (Source Transform Sink), hay phuong phap phan chia giao tac, dugc dung de phan chia thanh cac module.

(2 ) Thiet k£ hudng tien trinh

Phan mem bao gom hai yeu to' chuc n&ng va thong tin (du lieu) Trong viec phat trien phan mem truyen thong, phan tich v& thiet ke da dugc tien h&nh d|t trpng tam v&o chuc n3ng do phan mem thuc hien Dieu nay dugc ggi la thiet ke hudng tien trinh hay cach tiep c§n hirdng thiet ke Trong phuong phdp nay, khong cd chuan ro rang de djnh nghia don

vi chuc nSng, va do v£y viec djnh nghla nay cd the de dang bi anh hudng bdi c£ch nghi rieng cua ngudi thiet ke Ben c^inh do, khi cac chuc nSng dap ung cho yeu cau cua ngudi dung dugc thuc hi?n, thi khd dieu chinh cac yeu cau cho nhieu ngudi dur.g, va viec su dyng c6c chuc nSng chong ch£o nhau la khong the tranh khdi Ket qua la he thong bao gom nhieu chuc nang chong cheo nhau, la mgt trong nhung nhan to lam cho viec bao tri th&nh khd khan.

(3) Thiet ke hudng du* li$u

Du lieu khong thay doi bdi vl c3c yeu cau hay ddi hdi cua ngudi dung ve thao tic nghiep vy, nhung ton tai trong the gidi thyc bat ke den kieu, hay moi quan he, cua cac thao tac Vay, trong thiet ke t§p trung vao du lieu, su chu y dugc nham vao du lieu, va he thong dugc thiet ke dua tren cau true tien trinh du* lieu Hon nua, phuong phap thiet ke nay

da tien hoa thanh Cach tiep can hudng du lieu (DOA) Viec phan tich v& thiet ke dugc tien hanh cho du lieu, dugc tach b$ch vdi yeu cau hay ddi hdi cua ngudi dung ve thao tac, va do v£y cac tien trinh dugc xac dinh vk tich hgp vao trong

cac thu tyc chuyen dyng du li£u.

(4) Thiet ke hurdng doi tutfng

Thiet ke hudng doi tugng dugc suy ra bang viec nang cao hon cach tiep can hudng du lieu.

CD Khdi ni$m thie't ke hudng doi ttf^nig

Chung ta hay xem xet khai mem hudng doi im.rng qua xe hai lay lain vi du.

[Tinh 1-2-14 Doi tugng, du lieu va phuong phap (lay xe hoi lam vi dy)

“TJhuyerT55ng

D im g lai CCra mo va dong

D irge ffi&j khien bang vd 3ng

xe n3m ch6 ngoi TSnnhachet^o

Co bonbanh

Co bon cua

Co mpt than

Tieu ban cua xe hai: Class

Mpt xe rieng 1£: The hien hay doi tugng

Trang thai: Du lif u (Thuoc tinh)

H&nh vi: Dgng phap (Thu tyc)

Viec tich hgrp "trang tliai" va "hanh vi" dugc ggi la "bao bgc "

Horn nua, vifc che giau "trang th£i" v& "hanh vi" bang viec chua chung trong hgp den dugc ggi la "che giau thong tin" Dieu n&y dan toi viec cam truy nh$p true tiep vao du li§u, lam tang sy dgc lap cua doi tugmg va lam cho vijc dung lai dugc de dang hon.

Hinh 1-2-15 Vi dg ve bao bgc va che giau thong tin

Xe hai C he dau thGng tin

Tung th y c the dupe sinh ra tir mpt lop dupe gpi la ''the hi£n.'

Hinh 1-2-18 Vi du ve the hien (thyc the)