в 16:33, 26 мая 2010

2010-05-26T16:33:00Z

Admin: 1 версия

2010-05-26T12:46:42Z

1 версия

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==Configuration of LockType as a Property of the Recordset Object==



<source lang="vb">

Sub OptimisticRecordset()
Dim rst As ADODB.Recordset
Set rst = New ADODB.Recordset
rst.ActiveConnection = CurrentProject.Connection
rst.CursorType = adOpenStatic
rst.LockType = adLockOptimistic
rst.Open "Select * from Employees"
rst("City") = "Village"
rst.Update
Debug.Print rst("City")
rst.Close
Set rst = Nothing
End Sub
</source>

==Default Record Locking==



<source lang="vb">

Sub SetLocking()
Application.SetOption "Default Record Locking", 2
End Sub
</source>

==Set and get the lock type==



<source lang="vb">

Sub SetAndGetLocking(strLockType As String)
Dim intLockIndex As Integer
Dim strLockDesc As String
Select Case strLockType
Case "Optimistic"
intLockIndex = 6
Case "Exclusive"
intLockIndex = 1
Case "Pessimistic"
intLockIndex = 2
Case Else
intLockIndex = -1
End Select
If intLockIndex <> -1 Then
Application.SetOption "Default Record Locking", intLockIndex
End If
Select Case Application.GetOption("Default Record Locking")
Case 0
MsgBox "The default locking method is optimistic."
Case 1
MsgBox "The default locking method is exclusive."
Case 2
MsgBox "The default locking method is pessimistic."
End Select
End Sub
</source>

==Set Lock Type to adLockOptimistic==



<source lang="vb">

Sub SupportsMethod()
"Declare and instantiate a Recordset object
Dim rst As ADODB.Recordset
Set rst = New ADODB.Recordset

rst.ActiveConnection = CurrentProject.Connection
rst.CursorType = adOpenStatic
rst.LockType = adLockOptimistic
rst.CursorLocation = adUseServer
"Open the recordset, designating that the source
"is a SQL statement
rst.Open Source:="Select * from Employees ", _
Options:=adCmdText
"Determine whether the recordset supports certain features
Debug.Print "Bookmark " & rst.Supports(adBookmark)
Debug.Print "Update Batch " & rst.Supports(adUpdateBatch)
Debug.Print "Move Previous " & rst.Supports(adMovePrevious)
Debug.Print "Seek " & rst.Supports(adSeek)
rst.Close
Set rst = Nothing
End Sub
</source>

==use optimictic lock to open recordset==



<source lang="vb">

Private Sub Form_Open(Cancel As Integer)
Dim con As ADODB.Connection
Dim myRecordset As ADODB.Recordset
Dim strFrmNm As String

Set myRecordset = New ADODB.Recordset
Set con = New ADODB.Connection

con.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\store.mdb;"

myRecordset.Open "SELECT * FROM Employees", con, adOpenKeyset, adLockOptimistic
Set Me.Recordset = myRecordset

myRecordset.Close
con.Close
Set myRecordset = Nothing
Set con = Nothing
End Sub
</source>

==Use Row Level Locking==



<source lang="vb">

Sub SetGranularity()
Application.SetOption "Use Row Level Locking", True
End Sub
</source>

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VBA/Excel/Access/Word/Access/Lock - История изменений

в 16:33, 26 мая 2010

Admin: 1 версия