Posts tagged VBA

A function to reverse a string

Aug16
2007 1 Comment Written by admin

Very simple, uses the VBA function StrReverse to reverse the input string.

‘A function to reverse a string provided as input
‘For example, the string “abcd” will become “dcba”
‘Uses the VBA function StrReverse
Public Function ReverseString(sInputString As String) As String
On Error GoTo ReverseString_Error
    
ReverseString = StrReverse(sInputString)
    Exit Function

ReverseString_Error:
    ReverseString = “#ERROR#”
End Function

Posted in String Operations, Useful Procedures - Tagged ,

Concatenate function

Jul24
2007 Leave a Comment Written by admin

Oh, man, I can’t tell how useful that concatenate function is.

One repetitive use I found is to create OR/AND conditions for Access queries. I copy-paste the field values of a column from Access, do some filtering and my conditions are ready. Then I use this concatfunc to create a string to use in my Access query.

For example, look at this print screen:

The Range A1:A4 houses the string condition I want to use in my Access query to restrict the fruits from my data. In cell B1 I have the formula

=PERSONAL.XLS!concatfunc(A1:A4,CHAR(34) & ” or ” & CHAR(34))

, and the return string from this function is listed in cell B1.

Now, all you have to do is copy and paste this in Access criteria and put a quotation mark at the start and at the end of this string.

I have found one more use of this when I want to store some values in an Array, using the Array function in VBA.

One more print screen:

In this example, I insert a comma (CHAR(44) instead of string OR, and this function returns a string that I can use in VBA to store these values in an array using Array function, after adding a quotation mark, of course, at the start and at the end.

Posted in String Operations, Useful Procedures - Tagged ,

Access VBA: Convert Access tables to arff format

Jul18
2007 2 Comments Written by admin

Weka, an open source data mining software, uses arff input data format. You can use this code to convert any Access table to arff format. Download the Access database with code: Convert2Arff.mdb

This can very well be designed using forms, but this should get one started. Use Alt + F11 to see the code, then execute procedure ConvertTbl2Arff to convert a table.

Some highlights of this procedure
- Takes care of spaces in Attribute name and data values
- Finds unique values of nominal variables
- Assigns equivalent ARFF datatype
- Replaces missing values with question marks

Posted in Access, Useful Procedures - Tagged

Access VBA: Export Access tables using ODBC

Jul18
2007 3 Comments Written by admin

If you want to export Access tables using ODBC/DSN connections, use the following code. This procedure uses the File DSN and ODBC connection to export Access tables using DAO object TableDef.

Sub ExportTbls()

Dim sTblNm As String
Dim sTypExprt As String
Dim sCnxnStr As String, vStTime As Variant
Dim db As Database, tbldef As DAO.TableDef

On Error GoTo ExportTbls_Error

sTypExprt = “ODBC Database” ‘Export Type
sCnxnStr = “ODBC;DSN=DSNName;UID=userID;PWD=password” ‘Create the connection string

vStTime = Timer
Application.Echo False, “Visual Basic code is executing.”

Set db = CurrentDb()

‘need a reference to Microsoft DAO 3.x library
For Each tbldef In db.TableDefs
‘Don’t export System and temporary tables
If Left(tbldef.Name, 4) “MSys” And Left(tbldef.Name, 4) “~TMP” Then
‘Debug.Print tbldef.Name
sTblNm = tbldef.Name
DoCmd.TransferDatabase acExport, sTypExprt, sCnxnStr, acTable, sTblNm, sTblNm
End If
Next tbldef

MsgBox “Done! Time taken=” & Timer – vStTime

On Error GoTo 0
SmoothExit_ExportTbls:
Set db = Nothing
Application.Echo True
Exit Sub

ExportTbls_Error:
MsgBox “Error ” & Err.Number & ” (” & Err.Description & “) in procedure ExportTblsODST”
Resume SmoothExit_ExportTbls
End Sub

Posted in Access, Useful Procedures - Tagged ,

Access VBA: Delete tables from Access database

Jul18
2007 Leave a Comment Written by admin

If you want to delete all or some of the tables from your Access database, you can use this DAO approach. You would need a reference to Microsoft DAO 3.x object library. As shown in the example, you can use an array to store the table names, which you want to keep or delete.

Sub DelteTbls()
Dim sTblNm As String
Dim db As Database, tbldef As DAO.TableDef
Dim i As Integer, Arr As Variant

On Error GoTo DelteTbls_Error
‘You can use an array if you want to delete or not delete specific tables
‘Arr = Array(“Table1″,”Table2″,”Table3″)

Set db = CurrentDb() ‘Set the database object

‘Set the warnings off to suppress messages
DoCmd.SetWarnings False

‘For i = 0 To UBound(Arr)
    For Each tbldef In db.TableDefs
        ‘here you can use equal to or not equal to delete or keep specific tables
        ‘If Left(tbldef.Name, 4) = Arr(i) Then
        ‘Don’t delete System or temporary tables
        If Left(tbldef.Name, 4) “MSys” And Left(tbldef.Name, 1) “~” Then
              Debug.Print tbldef.Name
              sTblNm = tbldef.Name
              ‘Delete table
              DoCmd.DeleteObject acTable, sTblNm
        End If
    Next tbldef
‘Next i

MsgBox “Done!”

On Error GoTo 0

SmoothExit_DelteTbls:
    Set db = Nothing
    DoCmd.SetWarnings True
    Exit Sub

DelteTbls_Error:
    MsgBox “Error ” & Err.Number & ” (” & Err.Description & “) in procedure DelteTbls”
    Resume SmoothExit_DelteTbls
End Sub

Posted in Access, Useful Procedures - Tagged
« Older Entries Newer Entries »