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CompareBookmarks Method Example (VB)

This example demonstrates the CompareBookmarks method. The relative value of bookmarks is seldom needed unless a particular bookmark is somehow special.

Designate a random row of a Recordset derived from the Authors table as the target of a search. Then display the position of each row relative to that target.

'BeginCompareBookmarksVB

    'To integrate this code
    'replace the data source and initial catalog values
    'in the connection string
    
Public Sub Main()
    On Error GoTo ErrorHandler
    
     ' recordset and connection variables
    Dim rstAuthors As ADODB.Recordset
    Dim Cnxn As ADODB.Connection
    Dim strSQLAuthors As String
    Dim strCnxn As String
    
     ' comparison variables
    Dim count As Integer
    Dim target As Variant
    Dim result As Long
    Dim strAnswer As String
    Dim strTitle As String
    strTitle = "CompareBookmarks Example"
    
    ' Open a connection
    Set Cnxn = New ADODB.Connection
    strCnxn = "Provider='sqloledb';Data Source='MySqlServer';" & _
        "Initial Catalog='Pubs';Integrated Security='SSPI';"
    Cnxn.Open strCnxn

     ' Open recordset as a static cursor type recordset
    Set rstAuthors = New ADODB.Recordset
    strSQLAuthors = "SELECT * FROM Authors"
    rstAuthors.Open strSQLAuthors, Cnxn, adOpenStatic, adLockReadOnly, adCmdText
    
    count = rstAuthors.RecordCount
    Debug.Print "Rows in the Recordset = "; count
    
     ' Exit if an empty recordset
    If count = 0 Then Exit Sub
    
     ' Get position between 0 and count -1
    Randomize
    count = (Int(count * Rnd))
    Debug.Print "Randomly chosen row position = "; count
     ' Move row to random position
    rstAuthors.Move count, adBookmarkFirst
     ' Remember the mystery row
    target = rstAuthors.Bookmark
    
    count = 0
    rstAuthors.MoveFirst
         ' Loop through recordset
    Do Until rstAuthors.EOF
       result = rstAuthors.CompareBookmarks(rstAuthors.Bookmark, target)
       
       If result = adCompareNotEqual Then
          Debug.Print "Row "; count; ": Bookmarks are not equal."
       ElseIf result = adCompareNotComparable Then
          Debug.Print "Row "; count; ": Bookmarks are not comparable."
       Else
          Select Case result
             Case adCompareLessThan
                strAnswer = "less than"
             Case adCompareEqual
                strAnswer = "equal to"
             Case adCompareGreaterThan
                strAnswer = "greater than"
             Case Else
                strAnswer = "in error comparing to"
          End Select
            'show the results row-by-row
          Debug.Print "Row position " & count & " is " & strAnswer & " the target."
       End If
       
       count = count + 1
       rstAuthors.MoveNext
    Loop
    
    ' clean up
    rstAuthors.Close
    Cnxn.Close
    Set rstAuthors = Nothing
    Set Cnxn = Nothing
    Exit Sub
    
ErrorHandler:
    ' clean up
    If Not rstAuthors Is Nothing Then
        If rstAuthors.State = adStateOpen Then rstAuthors.Close
    End If
    Set rstAuthors = Nothing
    
    If Not Cnxn Is Nothing Then
        If Cnxn.State = adStateOpen Then Cnxn.Close
    End If
    Set Cnxn = Nothing
    
    If Err <> 0 Then
        MsgBox Err.Source & "-->" & Err.Description, , "Error"
    End If
    
End Sub
'EndCompareBookmarksVB
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