HOWTO: Use RDO and ODBC Text Driver to Open a Delimited Text

ID: Q187670

The information in this article applies to:

Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0

SUMMARY

RDO may be used with the ODBC Text driver to open and browse a delimited text file.

MORE INFORMATION

The Text ODBC driver relies on the Microsoft Jet 32-bit IISAM driver (MSText35.dll) that provides the services required for accessing text files. You can either link/attach to a Microsoft Access database or directly open text files. Because RDO must use Jet to access the text file, you will incur the additional overhead associated with loading Jet.

NOTE: This requires a Schema.ini file in the same path as the delimited text file. You must change the columns in the Schema.ini file to correspond to your delimited file. Also, you must change the path in the connect string to the correct path for your file.

To create a schema.ini file, use a simple text editor such as Notepad. Below are the schema.ini entries for the SAMPLE2.TXT file listed at the bottom of this article:


   [SAMPLE2.TXT]
   ColNameHeader = False
   Format = CSVDelimited
   CharacterSet = ANSI
   Col1=ProductID short
   Col2=ProductName char width 30
   Col3=QuantityPerUnit char width 30
   Col4=UnitPrice currency
   Col5=Discontinued bit

For more information on Schema.ini, see the REFERENCES section of this article.

Step-by-Step Example

Open Visual Basic, and create a new Project. Form1 is created by default.

Set a reference to Microsoft Remote Data Object 2.0 with the Project-References menu selection.

Paste the following code in the Form-Load event:


      Dim cn As New RDO.rdoConnection
      Dim en As RDO.rdoEnvironment
      Dim rs As RDO.rdoResultset
      Dim fld As RDO.rdoColumn

      Set en = rdoEngine.rdoEnvironments(0)

      With cn
          .CursorDriver = rdUseOdbc
          'The DBQ parameter below, is the path to your
          'Comma Delimited file(s). You may open multiple files
          'on the same connection in this path.
          .Connect = "DRIVER={Microsoft Text Driver (*.txt;" & _
                  " *.csv)};DBQ=E:\Samples\Text\CommaDelimited;"
          .EstablishConnection rdDriverNoPrompt, False
      End With

      'Jet uses '.' internally as an identifier for table names,
      'such as database.table. Jet eliminates ambiguity by mapping '#'
      'as the delimiter for external files.
      Set rs = cn.OpenResultset("select * from [sample2#txt]")

      While Not rs.EOF
          For Each fld In rs.rdoColumns
              Debug.Print fld.Name & "=" & fld.Value
          Next fld
          rs.MoveNext
      Wend

NOTE: In the example above, DBQ is not a valid parameter of the RemoteData control or the rdoConnection object's Connect property. It is supported by the Microsoft Jet database engine, and not by the ODBC driver.

You could copy and paste the following delimited file example into Notepad and save it as Sample2.txt. You could then modify the DBQ path, above, to point to the comma delimited file Sample2.txt.

1,Chai,10 boxes x 20 bags,$18.00,False
2,Chang,24 - 12 oz bottles,$19.00,False
3,Aniseed Syrup,12 - 550 ml bottles,$10.00,False
4,Chef Anton's Cajun Seasoning,48 - 6 oz jars,$22.00,False
5,Chef Anton's Gumbo Mix,36 boxes,$21.35,True
6,Grandma's Boysenberry Spread,12 - 8 oz jars,$25.00,False
7,Uncle Bob's Organic Dried Pears,12 - 1 lb pkgs.,$30.00,False

(This will give you seven records to test with in the sample code.)

NOTE: Make sure when you paste it in Notepad that you do not leave any blank lines at the top of the file.

You may choose an alternative to the comma delimiter by indicating the delimiter in the Schema.ini file e.g. Format = Delimited(*). You can use any character for the delimiter except the double (") quotation mark.

This same technique can be applied to fixed-width files by indicating 'FixedLength' for the Format, such as Format = FixedLength.

REFERENCES

"Working with Text Files", MSDN

"Using DAO to Connect to ODBC Data Sources", MSDN.

"RDO Compared to Microsoft Jet/DAO", MSDN.

"Text Data Source Initialization Settings", MSDN.

"External ISAM Driver Components", MSDN.

"Understanding Schema.ini Files", MSDN.

For additional information, please see the following article in the Microsoft Knowledge Base:

Q155512 : ACC: How to Create a Schema.ini File Programmatically.

Additional query words: kbdse kbDSupport kbVBp500 kbvbp kbRDO kbODBC kbVBp600

Keywords : kbGrpVBDB
Version :
Platform : WINDOWS
Issue type : kbhowto