Exporting and Importing Data in Text Format

Exporting and Importing Data in Text Format.

This is exporting data as a continuous stream of characters in text format.  The text is then sent through the Internet as an E-mail attachment to the target remote location. A cost-effective, quick data exchange over the Internet. 

At the receiving end, the Text data is converted back into its original form, as per the predefined Table Structure, and added to an existing data table.  No field delimiters, field names, or other details are sent along with the actual data lines.  The Source and Target Tables should have identical Structures known only to end users.

Let us take a quick look at some sample data and how it appears when converted to Text Format.

Sample MS Access Table: Export

Right-click to open the large image in a new Tab or Window.

MS Access Table: Export text data-image, when exported into Text File: Export.txt.

Right-click to open the large image in a new Tab or Window.

As shown in the text image, each record in the Access table named Export is converted into a continuous stream of characters and written into a text file, with each record occupying a separate line. The text file is saved with the same name as the source table, using the .txt file extension (Export.txt).

The first two data fields in the Source Table are Text Fields (field size 15 characters each), the third field is Date type, and the next five fields are Numeric type.

Data Field details are given below:

Seq	Field	Type	Size
1.	LastName	Text	15
2.	FirstName	Text	15
3.	DofB	Date
4.	Height	Number	Integer
5.	Weight	Number	Long Integer
6.	H	Number	Single
7.	W	Number	Double
8.	Dcml	Number	Decimal

The VBA txtExport() Function Code

The VBA program below reads the MS Access Table record by record, converts it to text format, and writes it to a Text File with the same name as the source table.  The text file Export.txt is created in the Default Database Folder.  I have created the sample data Table Export for Demo purposes only.  You can use any Table from your database, but see that it doesn’t contain any field types other than text, date, or Number.

Public Function txtExport(ByVal tblName As String)
'-----------------------------------------------------
'Purpose: Export Data into Text Format
'Author : a.p.r.pillai
'Date   : June, 2013
'Remarks: All Rights Reserved by www.msaccesstips.com
'-----------------------------------------------------
'Data Types
'----------
'Text - 10 = Actual size
'Date - 8 = 10 characters
'Integer - 3
'Long Integer - 4
'Single - 6
'Double - 7
'Decimal - 20
'Numeric types 3,4,6,7 or 20 = 12 characters

Dim tblSize() As Variant
Dim db As Database, rst As Recordset
Dim fld As Field, fldCount As Integer
Dim j As Integer, tbldef As TableDef
Dim numSize As Integer, dtSize As Integer
Dim fmt As String, outTxt As String
Dim outFileName As String

On Error GoTo txtExport_Err

numSize = 12
dtSize = 10

'Exported Text Filename is same as Tablename with file-extension .Txt
outFileName = tblName & ".txt"

Set db = CurrentDb
Set tbldef = db.TableDefs(tblName)
fldCount = tbldef.Fields.Count - 1
'A singly dimensioned Array of Variant Type 
'is decalred for number of fields in the Table. 
ReDim tblSize(fldCount) 

'The Array is initialized with text data type 
'for appropriate size to hold text, date & Numeric Values 
For j = 0 To fldCount 
   Set fld = tbldef.Fields(j) 
   Select Case fld.Type 
      Case 3, 4, 6, 7, 20 'Numeric data type 
        tblSize(j) = String(numSize, "0") 
      Case 8 'Date Data type 
        tblSize(j) = String(dtSize, "0") 
      Case 10 'Text data type 
        tblSize(j) = String(fld.Size, "x") 'Actual Text Field-size 
    End Select Next 

'Open the Source Table 
    Set rst = db.OpenRecordset(tblName) 
    'Create and open the output text file in the same folder of the database 
    Open outFileName For Output As #1 
    'Read records till the end of Table and convert them into text format 
    Do While Not rst.EOF 
       For j = 0 To fldCount 
          Set fld = tbldef.Fields(j) 
          Select Case fld.Type 
             Case 3, 4, 6, 7, 20 
                fmt = "00000000.000" 
                'position data right-aligned into the text variable 
                RSet tblSize(j) = Format(rst.Fields(j).Value, fmt) 
             Case 8 
                fmt = "dd/mm/yyyy" 
                'position data right-aligned into the text variable 
                RSet tblSize(j) = Format(rst.Fields(j).Value, fmt) 
             Case 10 
                'position data left-aligned into the text variable 
                LSet tblSize(j) = rst.Fields(j).Value 
          End Select 
       Next 
       outTxt = "" 
       For j = 0 To fldCount 
          'join all text data variables into a single text line 
          outTxt = outTxt & tblSize(j) 
       Next 
          'Write into text file 
       Print #1, outTxt 
       'take next record to export 
   rst.MoveNext 
Loop 

'Close the Text File and other files 
Close #1 
rst.Close 
db.Close 

Set db = Nothing 
Set tbldef = Nothing 
Set fld = Nothing 

txtExport_Exit: 
Exit Function 

txtExport_Err: 
MsgBox Err & " : " & Err.Description, , "txtExport()" 
Resume txtExport_Exit 
End Function

Running the Code

You can run the Program directly from the Debug Window Command line:

Syntax: txtExport "Table Name"

txtExport "Export"

Or run it from a Command Button Click Event Procedure

Private Sub cmdRun_Click()
txtExport "Export"
End Sub

The Data Format Change.

1. When Text Type Field values are converted to output text, the actual field size is calculated, and the data is left-aligned, and the balance area is filled with spaces. If the field value is shorter than the field size, the blank positions are filled with spaces.
2. Date Field uses 10 characters (dd/mm/yyyy) when converted to text.
3. All Numeric Field Values are converted to a 12-character text type and positioned right-aligned in the output memory image, left-filled with zeroes.

NB: Date and Numeric Data text field sizes (Date=10, Number=12) are selected arbitrarily and can be modified if needed.  The MS Access Table should have only the three Data types (Text, Date & Number) Fields.

The Text File created from the MS Access Table can be sent via email attachment to the remote location.  The VBA Program below converts the Text File back into Access Data and appends it to the Table with the same structure as the Source Table.

Public Function txtImport(ByVal txtFileName As String)
'txtFileName is same as Tablename with file-extension .txt
'-----------------------------------------------------
'Purpose: Import Text-Data into Table
'Author : a.p.r.pillai
'Date   : June, 2013
'Remarks: All Rights Reserved by www.msaccesstips.com
'-----------------------------------------------------
'Data Types
'----------
'Text - 10 = Actual size
'Date - 8 = 10 characters
'Integer - 3
'Long Integer - 4
'Single - 6
'Double - 7
'Decimal - 20
'Numeric types 3,4,6,7 or 20 = 12 characters

Dim tblSize() As Variant
Dim db As Database, rst As Recordset
Dim fld As Field, fldCount As Integer
Dim j As Integer, tbldef As TableDef
Dim numSize As Integer, dtSize As Integer
Dim fmt As String, outTxt As String
Dim inputFileName As String, I As Integer, k As Integer

On Error GoTo txtImport_Err

numSize = 12
dtSize = 10

inputFileName = txtFileName & ".txt"
Set db = CurrentDb
Set tbldef = db.TableDefs(txtFileName)
fldCount = tbldef.Fields.Count - 1

'A singly dimensioned Array of Variant Type
'is decalred for number of fields in the Table.
ReDim tblSize(fldCount)

'The Array is initialized with text data type
'for appropriate size to hold text, date & Numeric Values
For j = 0 To fldCount
   Set fld = tbldef.Fields(j)
   Select Case fld.Type
      Case 3, 4, 6, 7, 20 'Numeric data type
          tblSize(j) = String(numSize, "0")
      Case 8 'Date data type
          tblSize(j) = String(dtSize, "0")
      Case 10 'Text Field
          tblSize(j) = String(fld.Size, "x") ' Actual Text Field-size
   End Select
Next

'Open the Target Table Export
Set rst = db.OpenRecordset(txtFileName)

'Open the input text file
Open inputFileName For Input As #1

'Read the Text file, convert and add the data to the Target Table
  Do While Not EOF(1)
   'Read text data line
   Input #1, outTxt
   I = 1 'first field value off-set
   'Add a new record into the table
   rst.AddNew

   For j = 0 To fldCount
      Set fld = tbldef.Fields(j)
      'read data size for extracting correct number of characters
      'from the text line
      k = Len(tblSize(j))
     
      Select Case fld.Type 'check the current field type
         Case 3, 4, 6, 7, 20 'if numeric data type then
          'Extract numeric data, convert and write into data field
            rst.Fields(j).Value = Val(Mid(outTxt, I, k))
            I = I + k 'increment to next field off-set
         Case 8 'if it is date then
          'Extract Date data, convert and write into data field
            rst.Fields(j).Value = CDate(Mid(outTxt, I, k))
            I = I + k 'increment to next field off-set
         Case 10 'Text data type
          'Extract Date data, convert and write into data field
            rst.Fields(j).Value = Mid(outTxt, I, k)
            I = I + k 'increment to next field off-set
       End Select
    Next
      rst.Update
      'initialize the variable to read the next line of text data
      outTxt = ""
Loop

'No more text data in the file
Close #1
rst.Close
db.Close
Set db = Nothing
Set tbldef = Nothing
Set fld = Nothing

txtImport_Exit:
Exit Function

txtImport_Err:
MsgBox Err & " : " & Err.Description, , "txtImport()"
Resume txtImport_Exit

End Function

Debug Window Command Line Run Syntax:

txtImport "Text File Name"

txtImport "Export"

NB: Text File Name is entered without the file extension (.TXT). The Target Table should have the same structure as the Source Table.

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