tai lieu VB

7/31/2019 tai lieu VB

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LINH KIN PHN MM

& TRUY XUT DATABASE

Ch

ng 12


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Khoa Khoa hc & K thut my tnhTrng H Bch Khoa Tp.HCM

Mn Tin hcChng 12 : Linh kin phn mm & truy xut database

Slide 2

Tng qut v linh kin phn mm

Mc tiu ca qui trnh pht trinphnmmhngi tng lto ra ngdng c cu trc thunnht : tp cc itngsngv tng tc ln nhau.Mii tngcangdng c thc to ra theo cc cchsau :

nhngha Class Module mi cho itng.Dng Project.Add File thm file *.bas cha class module c snvo Project (y l 1 phng php thak thnh qu).Sdng cc iukhinsn c ca VB xy dng form giao din.Dng 'add components' thm cc iukhint file *.ocx vo dn.

Cc itng giao din cn cgi l linh kinphnmm.


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Slide 3

Cch to v dng linh kin phn mm

C 3 cch to linh kinphnmm ActiveX Control :Dng Project ActiveX EXE

Dng ActiveX DLLDng ActiveX Control.

Sau khi cto ra, vicsdng cc ActiveX Control hon tongingnhsdngmt control nhsnca VB.


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Slide 4

Thm ActiveX Control vo Project

dng 1 linh kinphnmm ActiveX Control trong 1 form caProject ngdng,trcht ta phi thm n vo cas Toolbox

ca Project theo qui trnh in hnh sau y :

1. n phi chut vo v tr trngca Toolbox, chn mc

Components


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Slide 5

Thm ActiveX Control vo Project (tt.2)

Ktip

2. Chn tab Controls,duyt v chn mc tngng, chn OK.


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Slide 6

Thm ActiveX Control vo Project (tt.3)

Cui cng

3. Ca s Toolbox

s cha cc iconmiu t cc Act.Control trongmodule va chn.


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Slide 7

Cch dng ActiveX Control

thyvic dng ActiveX Control hu xy dngphnmmddng nh th no, chng ta hy thvit 1 trnh duyt Web vi

chcnngtng tnh IE ca Microsoft, ta tmgingdngspvit ny l MyIE.Vicvitphnmmduyt Web tu rt kh khn v bncnphi trang bnhiukin thcnh : k thuthin thvnbn vha,kthut tng tc vingi dng thng qua bn phmv chut,kthut v qui trnh vit 1 chng trnh dch, lp trnhmng dng socket, giao thc truy xut ti nguyn Web HTTP(Hypertext Transfer Protocol), ngn ng DHTML,...Nhng ton b cc cng vic m 1 trnh duyt Web cn lm

c Microsoft ng gi trong 1 linh kin phn mm tn lWebBrowser.


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Slide 8

Cch dng ActiveX Control (tt)

ActiveX Control "WebBrowser" l 1 itng giao dinchcha 1 vng hinthni dung hnh chnhtviv tr v kch thc do ngilp trnh qui nh.

Interface ca n bao gm 3 loi : cc thuc tnh interface (khong 27), ccmethod (khong 12) v cc skin (khong 16) m ngi dng c th lptrnh thtcpng cho chng. y chng ta sgiithiu 1 s method mta dng trong vicvitngdng MyIE :

Navigate2 (URL,...) cho php download trang Web hay file *.doc, *.xls,*.ppt,... c xc nhbi URL, hinthni dung ca n ln vng hinth

rich v x l stng tc cangi dng (n vo vng lin kt,...).GoBack cho php quay v trang Web va truy xut (ngay trc trang hinhnh).GoForward cho php tinti trang Web (ngay sau trang hin hnh).GoHome cho php hinth trang ch.Refresh cho php download v hinthli trang hin hnh.Stop cho php dng ngay vic download v hinth trang Web hin hnh.ExecWB cho php thc thi 1 s hnh vi trn trang web nh thay i coch, in trang Web ra my in,...


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Slide 9

Giao din ngh ca trnh MyIE


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Slide 10

Chi tit cc option trong menu v toolbar (tt)


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Slide 11

Phn tch & thit k giao dinTrnh MyIE c giao din SDI gm 1 menu bar, 1 toolbar, 1 ComboBox lit kcc URL va truy xut, 1 ActiveX Control "WebBrowser" x l vic truy xut,

hin th cc trang Web v chphcv cc tng tc cangi dng. Quitrnh chi tit xy dngngdng MyIE sc trnh by trong bi thc hnhs 4, ych tm tt cc bc chnh :

To project loi "VB Application Wizard" v trli cc bc Wizard toProject.Chn Tools.Menu Editor to menu bar theo ctca slide trc. Qui

trnh dng Menu Editor cgiithiu trong chng 4.Cngclichng 4 bit qui trnh to/hiuchnh Toolbar.to(v) ComboBox nhp URL mi v lit k cc URL truy xut.to(v) control "WebBrowser". Khng cnv ComboBox v WebBrowserchnh xc v code s xc nhngmilncaschng trnh thay i.to th tcx l skin cho cc menu option v toolbar button rivitcode cho chng. Code ca cc th tc ny chyu lm "c" v gi ccmethod tngng trong itng WebBrowser thc thi.


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Slide 12

Phn tch & thit k giao din (tt)

Lu rngtrc khi thitkc giao dinca trnh MyIE, bncn 'add' cc linh kin ActiveX Control sau y :

Microsoft Common Dialog Control 6.0.Microsoft Internet Control.Microsoft Windows Common Controls 6.0.

Lu rng qui trnh Wizard cho loi Project SDI tosn chota 1 form ca chng trnh tn l frmMain. Form ny cha

sn 1 menu bar, 1 Toolbar. Chng ta ch cn hiu chnh li 2thnh phn ny ch khng cnphitomi chng.


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Slide 13

Tng qut v truy xut databaseTrong chng 11, chng ta gii thiu qui trnh truy xutd liu trn ccfile. Mt trong cc dng file giithiu l Random File, file ny l danh sch

cc record d liu c cu trc v di ging nhau, mi record chanhiufield dliu, th d file cha cc hs sinh vin, file cha cc hs nh, filecha cc hsng x...Huht cc ngdnghin nay (nht l cc ngdngnghipv)uphitruy xut cc random file. Vicqun l cc random file bao gmnhiu tc vnh to file mi vi cu trc record c th, thm/bt/hiu chnh/duyt cc

record, tm kim cc record tha mn 1 tiu chun no ,...thchin cctc v trn (nht l tm kim record) hiuqu, tin cy, ta cnnhiukinthckhc nhau v phitnnhiu cng sc.Random file (vi 1 sscitin v tngcng)cgi l database quanh. C nhiu format database quan h khc nhau angc dng. giiphng cc ngdngkhivicqun l database, ngi ta xy dngng

dng c bit : DBMS (Database Management System). ng dng s nhDBMS truy xut database cd dng.


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Slide 14

V nguyn tc,ngdng VB (hay vitbng ngn ng khc) c th truy xut 1database bng 1 trong cc giao tiplp trnh sau y :

ADO (ActiveX Data Objects)

DAO (Data Access Objects)

ODBC (Open Database Connectivity)

DBMS-Specific Language

Direct to database (file)

Trong cc giao tip truy xut database trn ch c ADO l d dng hnc,i

as trnghp ta ch to trc quan cc ActiveX Control v khai bo ccthuc tnh ca chng l truy xutc database m khng cnvit code.Trong trnghpphivit code th cngrtngn v d dng.

Cc kiu lp trnh truy xut database


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Slide 15

Truy xut database dng ADO ActiveX Control

Truy xut database dng ADO thng qua cc ActiveX Control l phng php

truy xut database trc quan v d dng nht.

as cc database trn Windows do Access to ra trong mi file databasechanhiu table, mi table l danh sch n record c cu trc chung no .

Qui trnh in hnh truy xut cc record ca 1 table trong 1 database Access

c th dng cc itng sau :

Dng i tng ADODB trong th vin "Microsoft ActiveX Data Objects

2.x Library" c thlit k cc table trong 1 database Access.

Dng itng Microsoft Data Control 6.0 qun l 1 RecordSet cha

tp cc record ca 1 table tha mn 1 iukin no .

Dng itng Microsoft DataGrid Control 6.0 hinth cc record ca

1 Data Control v cho php user thm/bt/hiuchnh cc record.

thy r vic truy xut database l rtd dng, ta hy vit 1 ngdng truy

xut database dng Access c giao dinnh slide sau :


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Slide 16

TextEdit qui nh filecn truy xut.

ComboBox lit kcc Table trong file.

ADODC qun l ccrecord tha mn 1iu kin mong

mun (c th n ).

DataGrid hin thcc record trongADODC userkho st v hiu

chnh.

Giao din ngh ca v d


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Slide 17

Cc bc thc hin v d

Ta c th to project dng "Standard EXE", dng cc iukhin trong Form ta cn 'add' cc ActiveX Control sau vo

Project :Microosft Data Control 6.0 qun l 1 RecordSet cha tp ccrecord trong 1 table.Microsoft DataGrid Control 6.0 hin th cc record ca 1 DataControl v cho php user thm/bt/hiuchnh cc record.

Microsoft Common Dialog Control 6.0 hin thcasduyt filev chn file cn truy xut. dng c i tng ADODB trong Project, ta chn menuProject.References chnthvin sau :

Microsoft ActiveX Data Objects 2.x Library, vi x =1 | 2 | 3 | 4 | 5 ...

Thitktrc quan form theo slide trc,to cc thtcx l skin cho button Browse v skin Click cho ComboBox.


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Slide 18

' Th tc x l click button BrowsePrivate Sub cmdBrowse_Click()

' hin th dialog box duyt v chn fileCommonDialog1.ShowOpen

' hin th file c chn vo textboxtxtFileName.Text = CommonDialog1.FileName' duyt cc table v hin th tn ca chng vo ComboBoxListAccessTables (txtFileName.Text)

End Sub

' Th tc x l khi user chn Table trong danh schPrivate Sub cbTable_Click()

Adodc1.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;_Data Source=" & txtFileName.Text

Adodc1.RecordSource = cbTable.TextAdodc1.Refresh

End Sub

' Th tc phc v s kin form b thay i kch thc.Private Sub Form_Resize()

' v li DataGrid ph hp vi kch thc mi ca formScaleMode = vbPixelsRsList.Move 5, 60, Me.ScaleWidth - 10, Me.ScaleHeight - 65

End Sub

Chi tit cc th tc x l s kin


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Slide 19

Private Sub ListAccessTables(strDBPath As String)Dim adoConnection As ADODB.Connection, adoRsFields As ADODB.Recordset

While cbTable.ListCount 0 ' Xa danh sch hin hnhcbTable.RemoveItem 0

Wend' To 1 connection n file databaseSet adoConnection = New ADODB.ConnectionadoConnection.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & strDBPath' Duyt cc tables, 'add' tn ca tng table vo danh sch ComboBox.Set adoRsFields = adoConnection.OpenSchema(adSchemaTables)With adoRsFields

Do While Not .EOFIf .Fields("TABLE_TYPE") = "TABLE" ThencbTable.AddItem .Fields("TABLE_NAME")

End If.MoveNext

LoopEnd WithadoRsFields.Close ' ng v xa recordset cha cc tableSet adoRsFields = NothingadoConnection.Close ' ng v xa connection n file databaseSet adoConnection = Nothing

End Sub

Th tc to danh sch cc Table ca database


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Slide 20

V d 2 dng ADOnhngha DSN (Data source name) miu t file database, nu c bc ny,ngdng truy xut database thng qua tn lun l DSN m khng cnbitchnh xc v tr ngdn file database v my cha file database. Dng icon"ODBC ..." trong Control Panel ca Windows nhngha DSN.Trong ngdng ta dng i tng ADODB truy xut database theo quitrnh in hnh sau :

to 1 itng Connection miu t database cn truy xut.gi method OpenSchema trn itng Connection tm cc Table trn

database.khi user chn 1 Table (hay dng lnh SQL miu tiukin xc nhcc record), ta gi method Execute trn itng Connection to 1 itng RecordSet cha cc record tm c.duyt cc record trong RecordSet v x l chng theo yu cu.ng v xa RecordSet v lpli cc bc 3, 4 x l Table khc.

ng v xa cc i tng to ra gii phng b nh do chngchim.

G d d


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Slide 21

TextEdit qui nh filecn truy xut.

Button duyt v chnfile database.

ComboBox lit kcc Table trong file.

Listbox hin th ccrecord trong 1 Table chn ( xem chkhng hiu chnh).

Giao din ca v d 2

C h l ki


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Slide 22

Dim adoConnection As ADODB.Connection ' bin tham kho n ConnectionDim adoRsFields As ADODB.Recordset ' bin tham kho n RecordSet

' Th tc x l click button BrowsePrivate Sub cmdBrowse_Click()' hin th dialog box duyt v chn fileCommonDialog1.ShowOpen' hin th file c chn vo textboxtxtFileName.Text = CommonDialog1.FileName' duyt cc table v hin th tn ca chng vo ComboBox

ListAccessTables (txtFileName.Text)End Sub

' Th tc phc v s kin form thay b thay i kch thc.Private Sub Form_Resize()

' v li ListBox ph hp vi kch thc mi ca formScaleMode = vbPixels

RsList.Move 5, 60, Me.ScaleWidth - 10, Me.ScaleHeight - 65End Sub

Cc th tc x l s kin

Th d h h T bl d b


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Slide 23

Private Sub ListAccessTables(strDBPath As String)While cbTable.ListCount 0 ' Xa danh sch hin hnh

cbTable.RemoveItem 0Wend

' 1. To 1 connection n file databaseSet adoConnection = New ADODB.ConnectionadoConnection.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & strDBPath' 2. Duyt cc tables, 'add' tn ca tng table vo danh sch ComboBox.Set adoRsFields = adoConnection.OpenSchema(adSchemaTables)With adoRsFields

Do While Not .EOFIf .Fields("TABLE_TYPE") = "TABLE" Then

cbTable.AddItem .Fields("TABLE_NAME")End If.MoveNext

LoopEnd WithadoRsFields.Close ' ng v xa recordset cha cc tableSet adoRsFields = Nothing' lu vn m Connection n file database hu truy xut li

End Sub

Th tc to danh sch cc Table ca database

Th t hi i d d t b


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Slide 24

' Th tc x l click chn table trong ComboBoxPrivate Sub cbTable_Click()Dim fcount As Integer, rcount As Integer, strBuf As String

' 3. To i tng RecordSet cha cc record ca Table c chnSet adoRsFields = adoConnection.Execute("SELECT * FROM " & cbTable.Text)' 4. Duyt cc record trong RecordSet v hin th chng trong ListBoxWith adoRsFields

rcount = 0 ' ch s recordfcount = .Fields.Count ' s field trong tng recordDo While Not .EOF ' duyt tng record trong recordset

rcount = rcount + 1

strBuf = Str(rcount) & ": " & .Fields(0).ValueFor idx = 1 To fcount - 1 ' duyt tng field v ni kt vo chui strBufstrBuf = strBuf & ", " & .Fields(idx).Value

NextRsList.AddItem strBuf ' add chui kt qu vo Lisbox.MoveNext ' di chuyn n record k tip

LoopEnd WithadoRsFields.Close ' ng v xa recordsetSet adoRsFields = Nothing

End Sub

Th tc hin ni dung database

H t g d b g (g i)


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Slide 25

Hot ng debug (g ri)

Sau khi vit code cho ngdng xong, ta sthchy n xcnh xem n giiquytng yu cu khng. Thngngdng

chanhiuli sai thuc 1 trong 2 loi sau :Cc liv tvng (tn cc phn t, t dnh ring,..) v c phpca cc phntcu thnh ngdng. VB s pht hin cc li nyd dng v hin th thng bo li cho ta xem xt v sa cha.Thngli ny dsacha.

Cc livgiithutcangdng. VB khng th pht hin cc liny v chng thuc phm tr ng ngha. ngdng s chy theogii thutc miu t, ta phi tnh gi tnh ng/saiv giithut, nhng vic tm li gii thut thng rt kh. gip ngilp trnh d dng tm ra cc ligiithut, VB cung cp cng

c cho php h kim sot c qui trnh chy ng dng v truyxut cc bind liucachng trnh, cng c ny cgi l'Debug'.

Trng thi hot ng trong debug


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Slide 26

Trng thi hot ng trong debugTrong qu trnh debug, ngdngs 1 trong 2 trng thi sau :

Pause : trng thi cangdng trc khi chy hay khi dng li theo 1iukindng no cangi debug. VB s ghi nhlnhsp thi hnhtrc khi dng(lnhu tin cangdngnu n chabtuchy).Do tnh lchs, ta dng thutng PC - program counter ni v lnhny. trng thi ny, ngi debug c th xem gi trca cc bindliubitngdngchyng hay sai theo yu cu riiukhinvic thihnh tip theo cangdng, lc ny ngdngschuyn sang trng thi

Running.Running : trng thi m ngdngangchy cc lnhca n n khi ngp 1 iukindng thit lp trc, lc ny ngdngschuynvtrng thi Pause.

Trong qu trnh debug, ng dng trng thi Pause ch yu thi gian vngi debug tng tc vingdngchyu trng thi ny. Mi khi ng

dng c chy tip, n chuyn qua trng thi Running, nhng s nhanhchng chyn lnhdng v chuynv trng thi Pause (tr phi b 'block'ch I/O hay b 'loop' trong cc vng lp v tn).

Cc thao tc dng trong debug


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Slide 27

Cc thao tc dng trong debug

xem ni dung ca 1 bindliu,ngi debug c th :Chn menu Debug.Add Watch thm 1 biu thc (thng l bin dliu) vo cas Watch xem ni dung ca n.Chn menu Debug.Edit Watch hiuchnhbiuthc(thng l bindliu)hin hnh cas Watch (context, watch type).Dichutn tn bin trong cas code, 1 casnhcha gi trcabinschinthngi debug xem xt.

hinthcascha danh sch cc thtcangthchind dang (cc

thtclng nhau theo tht),ngi debug c th :Chn menu View.Call Stacks. xem v tr PC hin hnh (lnhspthchinktip),ngi debug c th :

Chn menu Debug.Show Next Statement (thng khi ngdngdngli,n shinth lnhchyktip - lnhbdngvi mu t cbit v cdumi tn l tri calnh).

Chn menu Debug.Set Next Statement thitlplnhcha cursor hinhnh l lnhchyktip (thay v lnhbdngtrc)

Thit lp im dng chng trnh


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Slide 28

Thit lp im dng chng trnhNuiukindng l v tr lnhcth th ngi debug c th :

Chn menu Debug.Clear All Breakpoints xa tt c cc im dng(breakpoint) hinti.imdng l v tr lnh m khi ngdngchy ngangqua sdngli v chuynvtrng thi Pause xem dliu.Chn menu Debug.Toggle Breakpoint thit lp/xaimdng lnhcha cursor hin hnh (c ththchin nhanh chcnng ny bng cchdi cursor nl tri calnhcnthitlp/xaimdngri click chut).

Nuchniukindngda vo s thay ini dung cabindliu hay

biuthc no th theo cch sau :Chn menu Debug.Add Watch, nhpbiuthc(thng l 1 bindliu)richniukindng "Break when value is True" hay "Break when valuechanges".Chn menu Debug.Edit Watch, hiuchnhbiuthchin hnh (thng l1 bind liu) richniukindng "Break when value is True" hay

"Break when value changes".Ta c th (v nn) thitlpnhiuiukindngngthi 'ro chn'lungthi hnh cachng trnh.

Cc lnh iu khin trong debug


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Slide 29

Cc lnh iu khin trong debugchytipngdngtv tr PC hin hnh, ngi debug c th :

Chn menu Run.Start btuchyngdng,ngdngchdng likhi gpiukindng no cthitlp.Chn menu Run.Continue chy tip tv tr PC hin hnh, ngdngchdngli khi gpiukindng no cthitlp.Chn menu Debug.Step Over chytip 1 lnhridngli (Pause), nulnh thi hnh l lnhgithtc th ton bthtcscchy.y llnh cho php thchintnglnh theo mcvm.

Chn menu Debug.Step Into chytip 1 lnhridngli (Pause), nulnh thi hnh l lnhgithtc th ngdngsdng li lnhu tincathtc.y l lnh cho php thchintnglnh theo mc vi m.Chn menu Debug.Step Out chytip cc lnh cn licathtchinhnh ri quay v v dngli sau lnhgithtc ny (Pause).Chn menu Debug.Run to Cursor chytipngdngtv tr PC hin

hnh nlnhcha cursor hin hnh ridngli (Pause).

Cc lnh iu khin khc


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Slide 30

Cc lnh iu khin khc

Khi ngdngtrng thi 'Pause', ngi debug c ththchincc lnh sau :

Chn menu Run.End kt thc vicchyngdng.Chn menu Run.Restart kt thc vicchyngdngribtuchylitu.Chn menu Run.Break dngtngtvicchyngdng,lnhang thchin s c nhdu ta d theo di. Chcnng

ny gip ta bitngdngangb 'loop' onlnh no. Nungdngangb 'block' chbinc I/O, s khng c lnh no cdnh duc.

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