Visual Basic 6.0 IT.khmer9.Net

University of Management and Economics UME Visual Basic 6.0

Lecturer: TONG SAMNIENG (MSc-IT) Phone: (017) 933 396 9- Data Access Object

Visual Basic 6.0

Database Application 1. Introduction:

eyIgdwgehIyfa Database RtUvEtman Application rYmTaMg Business logic. Database RtUv)anbegáIt

eLIgeday DBMS nig Application rYmCamYy Development tools dUcCa VB, VB2005, Java….

etIeFVIdUcemþcedIm,IeGay Development tools TaMgenaHGaceFVIkar)anCamYy Database enaHKW Data

Access. dUcenH Data Access KWCa Tool Edlpþl;nUv Objects sMrab;eFVIkarCamYy Database. Data Access

rYmman ³

DAO (Data Access Object)

RDO(Remote Data Access Object)

ADO(ActiveX Data Object)

ADO.NET: The new version of ADO

OO4O(Oracle Object for OLE)

JDBC(Java Database Connectivity)

……..

edaysareyIgeRbIR)as; plitpl Microsoft Visual Basic 6 and Ms Access dUcenHeyIgnwgsikSaEt DAO nig

ADO .

2. DAO (Data Access Object)

DAO Ca Library (pÞúkComponents) sRmab;[elakGñkGac Connect BI Application CamYy Database.

DAO mantYnaTIbkERb nigbBa¢¢¢ÚnTinñn½yBI Application mk Database nig BI Database mk

Application vij.

munnwgelakGñkGaceRbIR)as; DAO )anCadMbUgsUmelakGñkcUleTAFIkkñúg Project Menu eRCIserIs

yk References bnÞab;mkFIkyk Microsoft Office 12.0 Access Database Engine Object Library

Application

DAO

Database



Project Menu References Microsoft Office 12.0 Access Database Engine

Object Library

2.1. rebobebIk Database File (Microsoft Access File)

SyntaxTI1

]TahrN_

Option Explicit

Dim DB As DAO.Database

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Private Sub Form_Load()

Set DB = DBEngine.OpenDatabase("D:\Employee.accdb", False, False)

End Sub

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

SyntaxTI2

]TahrN_

Option Explicit


>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Dim DBVariable As DAO.Database Set DBVariable = DBEngine.OpenDatabase (DBName,[Options], [Read-Only])

Dim DBVariable As DAO.Database Set DBVariable = DAO.OpenDatabase (DBName,[Options],[Read-Only])




Set DB = DAO.OpenDatabase("D:\Employee.accdb", False, False)

End Sub

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

taragBnül;GMBI Syntax xagelI

smasFatukñúg Syntax

GFib,ay

DBVariable CaGefr Database Object EdltMNag[ Database File EdlelakGñk

cg;ebIk.

DBName Ca String EdltMNag[ Path nigeQµaH Microsoft Jet Database File b¤ Ca

Data Source Name (DSN) rbs; ODBC Data Source

Option

Ca Optional Argument EdlRtUve)aHtMéleTA[ Parameter nUvtMélBIrKW

True b¤ False.

- True : elakGñkebIk Microsoft Jet Database CalkçN³ Exclusive

Mode (Only one user can access) mann½yfaelakGñkcg;

karBarmineGaymanGñkepSgeTotebIk Database File enH CaBiess

enAelIRbB½n§ Network.

- False (Default): mann½yfaelakGñkebIk Microsoft Jet Database

CalkçNH Shared Mode(Multiple users can access).

Read-Only

- True : elakGñkebIk Database File kñúgkRmitmYyKWGacRtwmEtGan

Tinñn½yEtminGacEk lubral; Object EdlmanenAkñúg Database File

)aneLIy.

- False (Default): elakGñkebIk Database File kñúgkRmitmYy

EdlGacEk lubral; Object EdlmanenAkñúg Database File )an.

2.2 rebobebIk Microsoft Access File EdlmanCab; Password

SyntaxTI1

Dim DBVariable As DAO.Database Set DBVariable = DBEngine.OpenDatabase (DBName, [Options],

[ReadOnly],[Connection])



SyntaxTI2

Microsoft Access File Edlman Password KWtRmUv[man [Connection] EdlCa Optional

Argument mYyeTot. dUecñHRbsinebI Microsoft Access rbs;elakGñkmanCab; Password enaHelakGñk

RtUVve)aHtMél[ Connection Parameter edayP¢ab;CamYy Password eTACamYy ebIBMuenaHeTnwgman Error

ekIteLIg.

]TahrN_

Option Explicit

Dim DB As DAO.Database ......................................................................................................................................................................................................


Set DB = DAO.OpenDatabase("d:\Employee.accdb", False, False, ”;pwd=123”)

End Sub ......................................................................................................................................................................................................

2.3 kareRbIR)as; RecordSet Object rbs; DAO

RecordSet Object eRbob)aneTAnwg Table beNþaHGasnñ (Virtual Table) EdlmantYnaTIrkSaTuk

Tinñn½yenAkñúg Memory CabeNþaHGasnñbnÞab;BIelakGñk)anTajykTinñn½yBI Table cUlkñúg RecordSet Object.

munnwgelakGñkGaceFVIkarCamYYy RecordSet Object )anluHRtaEtelakGñkRbkasGefrNamYy[man

RbePTCa RecordSet Object Camunsin ehIyRtUv Set RecordSet Object enaH[eTATTYlykTinñn½yBI

Table b¤BI QueryNamYYy.

Syntax:

]TahrN_

Option Explicit


Dim Rs As DAO.RecordSet

…………………………………………………………………………………………………………………………………..


Dim DBVariable As DAO.Database Set DBVariable = DAO.OpenDatabase (DBName,[Options],[Read-Only],

[Connection])

Dim RS As DAO.RecordSet Set RS = DBVariable.OpenRecordSet(Name As String,[Type], [Options], [LockEdits] ) As RecordSet



Set DB = DAO.OpenDatabase("D:\Employee.accdb", False, False )

Set Rs = DB.OpenRecordSet(“tblEmployee”, dbOpenDynaset)

End Sub …………………………………………………………………………………………………………………………………..

taragBnül;GMBI Syntax énkareRbI RecordSet

Argument

GFib,ay

RS CaeQµaH RecordSet Object EdlelakGñkcg;ebIk

DBVariable Ca Database Object EdlelakGñkkMBugQrenAelIva

Name Ca String Parameter EdlGacCa Table b£ CaeQµaH Query b£ mYyCa

SQL Statement

[Type] Ca Optional Argument eRbIedIm,IbBa¢ak;BITRmg; RecordSet EdlelakGñk

cg;ebIkEdlBiBN’nalMGitenAtaragxageRkam

[Option] Ca Optional Argument EdleRbIedIm,IbBa¢ak;BIsiT§kñugkarbBa©ÚlTinñn½y

[LockEdits] Ca Optional Argument EdleRbIsRmab; Lock RecordSet enAeBlEdl

man User elIsBImñak;cUlmkdMeNIrkar Table EtmYy.

[Type] Argument:

dbOpenTable

- eFIVkarpÞal;enAelI Table

- GacbBa©Úl Ek lub nig GanTinñn½y)an

- minGaceRbICamYy SQL Statement b¤ Query )aneLIy

dbOpenDynaset

- eFIVkarenAelI Virtual Table

- Gac bBa©Úl Ek lub nig GanTinñn½y)an

- GaceRbICamYy SQL Statement b¤ Query )an.

karEkTinñn½ykñúg Table BI Users epSgeTotelakGñkGacemIleXIjtamry³

RecordSet EdlelakGñkkMBugebIk b:uEnþcMeBaHkarlub b¤bBa©ÚlTinñn½yfµIvij



elakGñkminGacemIleXIjBITinñn½yEdlERbRbYlenaHeLIy.

dbOpenDynamic

- eFIVkarenAelI Virtual Table

- Gac bBa©Úl Ek lub nig GanTinñn½y)an

- GaceRbICamYy SQL Statement b¤ Query )an

- karEk lub bBa©©ÚlTinñn½yTaMgGs;kñúg Table BI Users epSgeTot

elakGñkGacemIleXIjral;Tinñn½yTaMgGs; bnÞab;BImankarEk lub nig

bBa©ÚlTinñn½yfµI.

dbOpenSnapshot mann½yfaebIk RecordSet kñúgTRmg;mYyEdlelakGñkminGacemIleXIjral;

karpøas;bþÚrTinñn½yEdlmanenAkñúg Table edaysar User epSgeTot.

dbOpenForwardOnly

mann½yfaelakGñkebIk RecordSet kñúgTRmg;mYyKWGnuBaØat[EteFVIkarGan

Tinñn½yBI RecordSet b:ueNÑaH. b:uEnþminGnuBaØateGayeFIVkar Ek lub nig

bBa©ÚlTinñn½yfµIeLIy.

[LockEdits] Argument:

dbReadOnly eFVIkar Lock eTAelI Record edayminGnuBaØat[Ekral;Tinñn½yKWmann½y

faelakGñkGac)anRtwmEtGanTinñn½yBI RecordSet Etb:ueNÑaH.

dbPessimistic

cMeBaHlkçN³ Lock EbbenHmann½yfaenAeBlEdl User1 ebIk RecordSet

edIm,IEkelI Record NamYy ehIykñúgeBlenaHman User2 ebIk RecordSet

edIm,IEkelI Record enaHEdr eBlenaH User2 EdlcUlmkEktameRkayenaH

minGacmansiT§iEkeLIy RbsinebI User1 kMBugEtEk Record enaH (eRbI Edit

Method) . User2 mansiT§iEkluHRtaEt User1 )anEkrYcral;sin.



dbOptimistic

mann½yfaenAeBlEdl User1 ebIk RecordSet edIm,IEkelI Record Na

mYyehIykñúgeBlenaHman User2 ebIk RecordSet edIm,IEkelI Record

enaHEdr eBlenaH Users TaMgBIrsuT§EtmansiT§iEkelI Record enaHdUcKañ.

2.4 karbBa©ÚlTinñn½yeTAkñúg Table edayeRbI RecordSet

edIm,IbBa©ÚlTinñn½yeTAkñúg Table tamry³ RecordSet elakGñkRtUveRbI Syntax dUcxageRkam³

Syntax TI1

Syntax TI2

Syntax TI3

]TahrN_³ ]bmafaelakGñkman Database mYysßitenAkñúg “D:\Employee.accdb” nigman Table

mYyeQµaH tblEmployee EdlmanTRmg;dUcrUbPaBxageRkam³

RecordSetObject.AddNew RecordSetObject(index) = Value1 ………………………………..

RecordSetObject(indexN) = ValueN RecordSetObject.Update

RecordSetObject.AddNew RecordSetObject(“FieldName1”) = Value1 ………………………………..

RecordSetObject(“FieldNameN”) = ValueN RecordSetObject.Update

RecordSetObject.AddNew RecordSetObject!FieldName1 = Value1 ………………………………………..

RecordSetObject!FieldNameN = ValueN RecordSetObject.Update



Y Source Code .

Option Explicit


Dim Rs As DAO.RecordSet

……………………………………………………………………………………………………………………..


Set DB = DAO.OpenDatabase("D:\Employee.accdb", False, False)

Set Rs = DB.OpenRecordSet (“tblEmployee”, dbOpenDynaset)

End Sub

……………………………………………………………………………………………………………………..

Private Sub cmdAddNew_Click()

Rs.AddNew

Rs(0) = txtEmpID

Rs(1) = txtName

Rs(2) = txtSex

Rs(3) = txtPhone

Rs(4) = txtAddress

Rs.Update

End Sub

……………………………………………………………………………………………………………………..

b¤


Rs.AddNew

Rs(“EmpID”) = txtEmpID

Rs(“EmpName”) = txtName

Rs(“Sex”) = txtSex

Rs(“Phone”) = txtPhone

Rs(“Address”) = txtAddress

Rs.Update

End Sub

……………………………………………………………………………………………………………………..

b¤


Rs.AddNew

Rs!EmpID = txtEmpID



Rs!EmpName = txtName

Rs!Sex = txtSex

Rs!Phone = txtPhone

Rs!Address = txtAddress

Rs.Update

End Sub

……………………………………………………………………………………………………………………..

elakGñkGacbegáItGnuKmn_ (Sub Procedure) dUcxageRkam³

Sub AddToRS()

Rs(0) = txtEmpID

Rs(1) = txtName

Rs(2) = txtSex

Rs(3) = txtPhone

Rs(4) = txtAddress

End Sub

sUmelakGñksakl,gehA Sub Procedure xagelImkeRbIkñúg cmdAddNew_Click dUcxageRkam³

……………………………………………………………………………………………………………………..


Rs.AddNew

Call AddToRS

Rs.Update

End Sub

……………………………………………………………………………………………………………………..

2.5 karGanTinñn½yBI Table edayeRbI RecordSet

Syntax TI1

Syntax TI2

Variable1 = RecordSetObject(index)

…………….………. VariableN = RecordSetObject(indexN)

Variable1= RecordSetObject(“FieldName1”) ……………………

VariableN = RecordSetObject(“FieldNameN”)



Syntax TI3

]TahrN_

……………………………………………………………………………………………………………………..

Private Sub ReadToTextBox_Click()

txtEmpID = Rs(0)

txtName = Rs(1)

txtSex = Rs(2)

txtPhone = Rs(3)

txtAddress = Rs(4)

End Sub

……………………………………………………………………………………………………………………..

elakGñkGacbegáItGnuKmn_ (Sub Procedure) dUcxageRkam³

Sub ReadFromRS()

txtEmpID = Rs(0)

txtName = Rs(1)

txtSex = Rs(2)

txtPhone = Rs(3)

txtAddress= Rs(4)

End Sub

sUmelakGñksakl,gehA Sub Procedure xagelImkeRbIkñúg cmdReadToTextBox_Click dUcxageRkam³

……………………………………………………………………………………………………………………..

Private Sub cmdReadToTextBox_Click()

Call ReadFromRS

End Sub

……………………………………………………………………………………………………………………..2

2.6 kareRbI RecordSetObject.BOF Property

BOF (Begin of File) Ca Property mYyEdleRbIsRmab;bBa¢ak;faetI Table EdlelakGñkTajTinñn½y

mkkñúg RecordSet manTinñn½y b¤minTan;manTinñn½y. RbsinebImanTinñn½yenaH BOF mantMélesµI False

pÞúymkvijKW BOF mantMélesµI True.

Rs.BOF

Rs.MoveFirst

Rs.MoveNext

……..

Rs.MovePrevious

Rs.MoveLast

Rs.EOF

Variable1= RecordSetObject!FieldName1 ………………………

VariableN = RecordSetObject!FieldNameN



]TahrN_

……………………………………………………………………………………………………………………..

Private Sub ReadToTextBox_Click()

If Rs.BOF = False Then

Call ReadFromRS

Else

MsgBox “No data in your table!”

End If

End Sub

……………………………………………………………………………………………………………………..

2.7. kareRbI RecordSetObject.MoveFirst

Ca Method EdleRbIsRmab;rMkil Cursor eTAkan;TItaMg RecordTImYyrbs; RecordSet. Ca

Default KWTItaMg Record sßitenA MoveFirst.

]TahrN_

Private Sub cmdFirst_Click()

If Rs.BOF = True Then

MsgBox "No Data in table!", vbInformation

Else

Rs.MoveFirst

Call ReadFromRS

End If

End Sub

2.8. kareRbI RecordSetObject.MoveNext

Ca Method EdleRbIsRmab;rMkil Cursor eTAkan;TItaMg Record edaycab;BITItaMg Current Record

eTAmuxmþgmYy Record.

]TahrN_

Private Sub cmdNext_Click()


MsgBox "No data in table!", vbInformation

Else

Rs.MoveNext

If Rs.EOF = True Then

Rs.MoveLast

MsgBox "This is the Last Record!", vbInformation

Else

Call ReadFromRS

End If

End If

End Sub



2.9. kareRbI RecordSetObject.MoveLast

Ca Method EdleRbIsRmab;rMkil Cursor eTAkan;TItaMg Record cugeRkaybMputén RecordSet.

]TahrN_

Private Sub cmdLast_Click()


MsgBox "No data in table!", vbInformation

Else

Rs.MoveLast

Call ReadFromRS

End If

End Sub

2.10. kareRbI RecordSetObject.MovePrevious

Ca Method EdleRbIsRmab;rMkil Cursor eTAkan;TItaMg Record edaycab;BITItaMg Current Record

[fyeRkayvijmþgmYy Record.

]TahrN_

Private Sub cmdPrevious_Click()


MsgBox "No Data in Your Table!", vbInformation

Else

Rs.MovePrevious


Rs.MoveFirst

MsgBox "This is the First Record!", vbInformation

Else

Call ReadFromRS

End If

End If

End Sub

2.11. kareRbI RecordSetObject.RecordCount

Ca Property EdleRbIsRmab;rab;cMnYn Record EdlmanenAkññúg RecordSet.

]TahrN_

Private Sub cmdRecordCount_Click()


MsgBox “No data in your table!”

Else

Rs.MoveLast

MsgBox Rs.RecordCount & “ Records”

End If



End Sub

lT§pl³

2.12. kareRbI RecordSetObject.EOF

Ca Property mYyEdleRbIsRmab;RtYtBinitüemIlfaetI Cursor )anrMkildl;TIbBa©b;én Record ehIyb¤

enA RbsinebI Property enHTTYl)antMél True mann½yfa Cursor )anrMkildl;TIbBa©b;én Record ehIy

pÞúymkvijebITTYl)antMél False mann½yfa Cursor minTan;rMkildl;TIbBa©b;én Record eT.

]TahrN_³ ]bmafaelakGñkman ListView mYyeQµaH ListView1 enAeBlelakGñk Click elIbUtugeQµaHfa

cmdShowInList_Click enaHvanwgGanTinñn½ykñúg RecordSet TaMgGs;cUleTAkñúg ListView1.

Y Source Code .

Option Explicit ………………………………………………………………………………………………………………………………….

Sub AddColumnHeader(Lvw As Object, ParamArray Col())

Dim i As Integer

Lvw.ColumnHeaders.Clear

For i = 0 To UBound(Col)

Lvw.ColumnHeaders.Add , , Col(i)

Next i

Lvw.View = lvwReport

Lvw.GridLines = True

Lvw.FullRowSelect = True

Lvw.MultiSelect = True

End Sub ………………………………………………………………………………………………………………………………….

Sub AddDataToLvw(Lvw As Object, ParamArray Data())

Dim i As Integer

Set LItem = Lvw.ListItems.Add(, , Data(0))

For i = 1 To UBound(Data)

LItem.SubItems(i) = Data(i)

Next i

End Sub ………………………………………………………………………………………………………………………………….

Private Sub cmdShowInList_Click()




MsgBox "No data in your table!", vbInformation

Else

Call AddColumnHeader(ListView1,Rs(0).Name,Rs(1).Name,Rs(2).Name,

Rs(3).Name, Rs(4).Name)

Rs.MoveFirst

Do While Not Rs.EOF

Call AddDataToLvw (ListView1, Rs(0), Rs(1), Rs(2), Rs(3), Rs(4))

Rs.MoveNext

Loop

End If

End Sub ………………………………………………………………………………………………………………………………….

lT§pl³

2.13. kareRbI RecordSetObject.AbsolutePosition

Ca Property mYyEdlGac[elakGñkTTYl)annUvTItaMg Record EdlelakGñkkMBugQrenAelIvakñúg

RecordSet. ehIyProperty enHGaceRbI)anluHRtaEtelakGñkebIkRecordSet kñúgTMrg; dbOpenDynaset

Type cMeBaH Property enHvae)aHtMélsUnüRbsinebI RecordSet kMBugQrenATItaMg RecordTI1.

]TahrN_

Private Sub cmdNext_Click()


MsgBox "No data in Table!", vbInformation

Else

Rs.MoveNext


Rs.MoveLast

MsgBox "This is the Last Record!", vbInformation

Else

Call ReadFromRS

MsgBox “Records “ & Rs.AbsolutePosition + 1

End If

End If

End Sub



2.14. kareRbI RecordSetObject.Close

Ca Method eRbIsRmab;biT RecordSet EdlelakGñk)anebIk.

Syntax:

]TahrN_³ Rs.Close

rrrhsss

RecordSetObject.Close



3.ADODB

ADODB Ca Library mYyeTotrbs; Microsoft sMrab;eGay Developer eRbIR)as; sMrab;

Access Database. ADO KWCa Database Access components CMnan;fµIrbs; Microsoft

vaRtUv)an Microsoft eRbIR)as;cab;BI Visual Basic 6. cMnucBiessrbs; ADO:

- Using OLE DB Technology(Object Linking and Embedding, Database)

- Gac Distribute elII Internet mann½yfaeKGaceRbI ADO edIm,I Develop Web

Application dUcCa ASP.

- Support Clients/Server Cag DAO and Support Distributed Database.

Object and structure of ADODB

- Connection: Ca Object edIm,IP¢ab;cUl Database mann½yfaebIeyIgcg;sresrkUd

edayeRbI ADODB cUl Database NamYyeyIgRtUv Tajyk Database enaHtamry³

Connection Object rbs; ADODB.

- RecordSet: pÞúk Records rbs;EdlTajecjBI table,views

-Command³ Ca Object pÞúk Parameters edIm,I Execute Server subprogram dUcCa

Stored procedure or functions.

Note:

edIm,IeRbI ADODB GñkRtUvyk Reference Microsoft Active Data Objects 2.6 Library

3.1 Connection

edIm,I Connect cUl Database eyIgRtUv³

- begáIt Object Connection

Dim Cn as ADODB.Connection

Connection Connection

Command

RecordSet

Field

Field



Set Cn=new ADODB.Connection

- ebIk Connection edIm,ITaj Database dak;elI Connection

Cn.Open "Connection String"

Connection KWGaRs½yelI Database EdlmanTMrg;TUeTA³

ConnStr="Privider=OLE Provider;[Data Source="path/database name"]

OLE Privider CaeQµaH Database provider EdlsÁal;eday ADOdUcCa

DBMS Provider

Ms Access 2007 microsoft.ACE.oledb.12.0

Data source: Ca String GaRs½yelI DBMS ebI

Access: Path\filename.mdb

]TahrN_1 Connect cUl Access Database

Dim cn as ADODB.Connection

Set cn=new ADODB.Connection

cn.Open "Provider=microsoft.ACE.oledb.12.0;Data Source=C:\MyDb\db1.mdb"

3.2 RecordSet pÞúk Records Edl select ecjBI Database .

Syntax Open RecordSet

Open([Source], [ActiveConnection], [CursorType As CursorTypeEnum = adOpenUnspecified],

[LockType As LockTypeEnum = adLockUnspecified], [Options As Long = -1])

kñúgenaH

Source:Ca table name, Select SQL,View ,Query name or Stored Procedure name

Active Connection

This specifies which database to get the data from.

You can use two different methods, either:

A connection string (something like "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=c:\my

documents\DB1.mdb")

Cursor Type

The cursor type basically determines two things:

1) what methods you can use to move through the recordset (.MoveFirst/.MoveNext/..),

2) whether you see the changes to the data that other users have made since you opened the

recordset.

adOpenForwardOnly

This is the default. It is the fastest, and uses the least amount of memory and network traffic.

1) You can only use .MoveNext to move thru the records (not .MoveFirst etc).

2) You will not see changes to the data by other users since you opened the recordset.

objRS.Open "SELECT field1 FROM table1", objConn, adOpenForwardOnly, adLockReadOnly, adCmdText



Do while Not objRS.EOF

'do something with the data here!

Msgbox objRS.Fields("field1").Value

objRS.MoveNext

Loop

adOpenStatic

1) You can use any of the .Move methods (.MoveFirst/.MovePrev/..).

2) You will not see changes to the data by other users since you opened the recordset.

adOpenKeyset


2) You will see Some changes to the data (edited/deleted records only) by other users since you

opened the recordset.

adOpenDynamic


2) You will see All changes to the data (added/edited/deleted records) by other users since

you opened the recordset.

Lock Type

The lock type also determines two things:

1) whether you can make changes to the data (add/edit/delete),

2) how other users will be stopped from editing the same record as you.

adLockReadOnly

This is the default. It has the least amount of effect on other users, and is better in terms of

speed/memory/network usage.

1) You cannot add/edit/delete data, you can only read it.

2) You do not block other users from editing records in the table.

adLockOptimistic

1) You can add/edit/delete data.

2) When you edit a record, another user can edit it at the same time - but if you both try to

write the data, one of you will get an error when the .Update occurs.

adLockPessimistic

1) You can add/edit/delete data.

2) When you edit a record, it is immediately blocked from other users. An error will occur as

soon as any values are altered in the recordset (eg: objRs.Fields("Field1").Value = 10 ).

Depending on the database you are using, this may block multiple records, rather than just the

one you are editing!

Option:

kMNt;TMrg; Object EdlRtUv)an Open

man adCmdText ebI Source Ca SQL Select Statement

adCmdTable if Source is table,

adCmdStoredProcedure if source is stored procedure



and adCmdUnknown if unspecified object type .

]TahrN_

Private Sub Command1_Click()

Dim rst As New ADODB.Recordset

Dim sql As String

'sql = "select * from tblproduct"

'rst.Open sql, cnn

rst.Open ("select * from tblproduct"), cnn

Me.Text2.Text = rst(2)

End Sub

Disconnect recordset.

Set rs1.ActiveConnection = Nothing

3.3 Methods sMxan;²rbs; RecordSet

Methods sMxan;²rbs; ADODB.RecordSet manRbhak;RbEhleTAnwg DAO.RecordSet

MoveNext MovePrevious

MoveLast

MoveFirst

AddNew

Update

Delete

Close

edIm,IEk Record kñúg Database, ADO Kµan Method Edit eT dUcenHebIRtUvkarEk eyIgEk RYc

Update EtmþgeTA.



sMnYr niglMhat;

1> etIGVICa Data Access Object ? etIvamantYnaTIdUcemþcxøH?

2> cUrelakGñksresr Syntax edIm,IebIk Database File edayeRbI DAO?

3> etIGVICa RecordSet Object rbs; DAO?

4> cUrelakGñksresr SyntaxmYy edIm,IbBa©ÚlTinñn½yeTAkñúg Table edayeRbI RecordSet rbs; DAO ?

5> cUrelakGñksresr SyntaxmYy edIm,IGanTinñn½yecjBI Table edayeRbI RecordSet rbs; DAO ?

6> etI BOF mantYnaTIdUcemþcxøH?

7> etI MoveFirst mantYnaTIdUcemþcxøH?

8> etI MoveLast mantYnaTIdUcemþcxøH?

9> etI MoveNext mantYnaTIdUcemþcxøH?



10> etI MovePrevious mantYnaTIdUcemþcxøH?

11> etI EOF mantYnaTIdUcemþcxøH?

12> etI RecordCount mantYnaTIdUcemþcxøH?

lMhat;³ ]bmafaelakGñkman Database mYysßitenAkñúg “D:\Student.accdb” nigman Table

mYy eQµaHfa tblStudent(StudentID,StudentName,Phone) nigmanTRmg; Form

dUcrUbPaBxageRkam³

Y Source Code .

Option Explicit


Dim Rs As DAO.Recordset ………………………………………………………………………………………………………………………………….



Sub AddColumHeader(Lvw As ListView, ParamArray Col())

Dim I As Integer

For I = 0 To UBound(Col)

Lvw.ColumnHeaders.Add , , Col(I)

Next

Lvw.View = lvwReport

Lvw.FullRowSelect = True

Lvw.GridLines = True

End Sub ………………………………………………………………………………………………………………………………….

Sub addDataToLvw(Lvw As ListView, ParamArray Data())

Dim Litem As ListItem, I As Integer

Set Litem = Lvw.ListItems.Add(, , Data(0))

For I = 1 To UBound(Data)

Litem.SubItems(I) = Data(I)

Next

End Sub ………………………………………………………………………………………………………………………………….

Private Sub Timer1_Timer()

Dim X1 As String, X2 As String

X1 = Left(Me.Caption, 1)

X2 = Right(Me.Caption, Len(Me.Caption) - 1)

Me.Caption = X2 + X1

End Sub ………………………………………………………………………………………………………………………………….

Sub ShowInTextBox()

If Rs.BOF = True Then MsgBox "No data in table!", vbInformation: Exit Sub

Me.txtID.Text = Rs(0)

Me.txtName.Text = Rs(1)

Me.txtPhone.Text = Rs(2)

End Sub ………………………………………………………………………………………………………………………………….

Function AutoID() As String

Dim Rs1 As Recordset

Set Rs1 = DB.OpenRecordset("Select Max(studentID) from tblstudent")

Dim N As Long

If IsNull(Rs1(0)) Then

N = 1

Else

N = Right(Rs1(0), 4) + 1

End If

Set Rs1 = Nothing

AutoID = "S" & Format(N, "0000")

End Function ………………………………………………………………………………………………………………………………….




Set DB = DAO.OpenDatabase(Application.Path & "\Student.accdb", False,

False)

Set Rs = DB.OpenRecordset("select * from tblstudent order by studentid")

Me.txtID.Text = AutoID

Me.txtID.Enabled = False

Me.cmdSave.Caption = "New"

Call ShowInTextBox

Call AddColumHeader(Me.ListView1, "StudentID", "StudentName", "Phone")

Timer1.Enabled = True

Timer1.Interval = 250

End Sub ………………………………………………………………………………………………………………………………….

Private Sub cmdShow_Click()


ListView1.ListItems.Clear

Rs.MoveFirst

Do While Not Rs.EOF

Me.addDataToLvw ListView1, Rs(0), Rs(1), Rs(2)

Rs.MoveNext

Loop

Rs.MoveFirst

End Sub ………………………………………………………………………………………………………………………………….

Sub UnEnableButton()

Dim Ctl As Control

For Each Ctl In Me.Controls

If TypeOf Ctl Is CommandButton Then

Ctl.Enabled = False

End If

Next

Me.cmdSave.Enabled = True

End Sub ………………………………………………………………………………………………………………………………….

Sub EnableButton()

Dim Ctl As Control

For Each Ctl In Me.Controls

If TypeOf Ctl Is CommandButton Then

Ctl.Enabled = True

End If

Next

End Sub ………………………………………………………………………………………………………………………………….

Sub AddtoRecordset()

Rs(0) = Me.txtID.Text

Rs(1) = Me.txtName.Text



Rs(2) = Me.txtPhone.Text

End Sub ………………………………………………………………………………………………………………………………….

Private Sub cmdSave_Click()

If Me.cmdSave.Caption = "New" Then

txtID.Text = AutoID

txtName.Text = ""

txtPhone.Text = ""

txtName.SetFocus

Me.cmdSave.Caption = "Save"

Call UnEnableButton

Else

If Trim(txtName.Text) = "" Then

MsgBox "Please, input name of student!", vbInformation

txtName.SetFocus

Else

Rs.AddNew

Call AddtoRecordset

Rs.Update

Call cmdShow_Click

txtID.Text = AutoID

txtName.Text = ""

txtPhone.Text = ""

Me.cmdSave.Caption = "New"

Call EnableButton

End If

End If

End Sub ………………………………………………………………………………………………………………………………….

Private Sub cmdSearch_Click()

Dim SID As String

SID = InputBox("Please, input a StudentID for searching!")

If Trim(SID) = "" Then

MsgBox "Please, input a StudentID again!", vbInformation

Exit Sub

Else

Rs.MoveFirst

Rs.FindFirst "StudentID='" & Trim(SID) & "'"

If Rs.NoMatch = True Then

MsgBox "Not Found!", vbInformation

Else

Call ShowInTextBox

End If

End If

End Sub ………………………………………………………………………………………………………………………………….



Private Sub cmdDelete_Click()

Dim SID As String

SID = InputBox("Please, input a studentID for deleting!")

If Trim(SID) = "" Then

MsgBox "Please, input a studentID again!", vbInformation

Exit Sub

Else

Rs.MoveFirst

Rs.FindFirst "StudentID='" & Trim(SID) & "'"

If Rs.NoMatch = True Then

MsgBox "Not Found!", vbInformation

Else

Dim B As Variant

B = MsgBox("Are you sure, to delete this record!", vbYesNo)

If B = vbYes Then

Rs.Delete

MsgBox SID & " was deleted!", vbInformation

Call cmdShow_Click

End If

End If

End If

End Sub ………………………………………………………………………………………………………………………………….

Private Sub cmdUpdate_Click()

If Trim(txtID.Text) = "" Then

MsgBox "Please input StudentID!", vbInformation

txtID.SetFocus

ElseIf Trim(txtName.Text) = "" Then

MsgBox "Please input name of student!", vbInformation

txtName.SetFocus

Else

Dim B As Variant

B = MsgBox("Are you sure, to update this record!", vbYesNo)

If B = vbYes Then

Rs.Edit

Call AddtoRecordset

Rs.Update

Call cmdShow_Click

End If

End If

End Sub ………………………………………………………………………………………………………………………………….

Private Sub cmdFirst_Click()


Rs.MoveFirst

Call ShowInTextBox



Me.txtNo.Text = Rs.AbsolutePosition + 1

End Sub ………………………………………………………………………………………………………………………………….

Private Sub cmdLast_Click()


Rs.MoveLast

Call ShowInTextBox


End Sub …………………………………………………………………………………………………………………………………. Private Sub cmdNext_Click()


Rs.MoveNext


Rs.MoveLast

MsgBox "This is the last record!", vbInformation

Else

Call ShowInTextBox


End If

End Sub ………………………………………………………………………………………………………………………………….

Private Sub cmdPrevious_Click()


Rs.MovePrevious


Rs.MoveFirst

MsgBox "This is the first record!", vbInformation

Else

Call ShowInTextBox


End If

End Sub ………………………………………………………………………………………………………………………………….

rrrhsss

Visual Basic 6.0 IT.khmer9.Net

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