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Q272338: HOWTO: Use VFP and ADO Stream Object to Retrieve Binary Data

Article: Q272338
Product(s): Microsoft FoxPro
Version(s): WINDOWS:2.5,6.0; winnt:7.0
Operating System(s): 
Keyword(s): kbActiveX kbADO kbvfp600 kbSQLServ700 kbGrpDSFox kbDSupport kbADO250
Last Modified: 12-MAY-2001

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 6.0 
- ActiveX Data Objects (ADO), version 2.5 
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SUMMARY
=======

Visual FoxPro has the capability to handle Binary Large Object (BLOB) data from
providers like SQL Server by using ActiveX Data Objects (ADO) Stream objects and
recordsets.

A BLOB is a type of data column that contains binary data such as graphics,
sound, or compiled code. From the perspective of an application, this data is
"formless." In SQL Server, this data is commonly known as an "Image" data type.

MORE INFORMATION
================

The following code sample assumes that you have the necessary access and
privileges to a Microsoft SQL Server, and that you have the pub_info table in
the SQL Server 7.0 Pubs sample database.

1. In Visual FoxPro, create a new program.

2. Paste the following code into the new program:

  CLEAR
  CLEAR ALL
  RELEASE ALL
  #DEFINE LOC_SQLSERVERNAME	"MYSERVER"
  #DEFINE LOC_SQLUID		"SA"
  #DEFINE LOC_SQL_PWD	""

  LOCAL lcConnStr, lcSQL, loConnection, lcImageName, ;
  	loRecordSet, loADOStream

  lcConnStr="Provider=SQLOLEDB;" +;
  	"Data Source=" + LOC_SQLSERVERNAME + ";" +;
  	"Initial Catalog=PUBS;" +;
  	"UID=" + LOC_SQLUID + ";" +;
  	"Pwd=" + LOC_SQL_PWD

  lcSQL = "SELECT * FROM pub_info"

  *!* Creates the objects.
  loConnection = CREATEOBJECT("ADODB.Connection")
  loRecordSet = CREATEOBJECT("ADODB.Recordset")
  loADOStream = CREATEOBJECT("ADODB.Stream")

  *!* Open the connections.
  loConnection.OPEN(lcConnStr)
  loRecordSet.OPEN(lcSQL,loConnection,2,3)

  *!* Set Stream Object properties.
  loADOStream.TYPE = 1	&& 1=Binary Data, 2=Text Data.
  loADOStream.OPEN

  loADOStream.WRITE(loRecordSet.FIELDS("logo")) 	&& Pass data to the stream object.
  lcImageName = "BLOB.gif"                  		&& Sets the local file name.
  loADOStream.SaveToFile(lcImageName,2)         	&& Saves stream object to a file.
  @1,1 SAY CURDIR() + lcImageName BITMAP    		&& Displays image file

  *!* Close connections.
  loRecordSet.CLOSE
  loConnection.CLOSE
  loADOStream.CLOSE

  ERASE CURDIR() + "BLOB.gif"

3. Change the three #DEFINE statements to reflect your local setup, and then
  save and run the program.

4. Observe the image on the Visual FoxPro desktop.

(c) Microsoft Corporation 2000, All Rights Reserved. Contributions by Reinaldo
Torrales, Microsoft Corporation.


REFERENCES
==========

For additional information, click the article number below to view the article
in the Microsoft Knowledge Base:

  Q258038 HOWTO: Access and Modify SQL Server BLOB Data by Using the ADO Stream
  Object

Additional query words: BLOB, AppendChunk, GetChunk

======================================================================
Keywords          : kbActiveX kbADO kbvfp600 kbSQLServ700 kbGrpDSFox kbDSupport kbADO250 
Technology        : kbVFPsearch kbAudDeveloper kbADOsearch kbADO250 kbVFP600
Version           : WINDOWS:2.5,6.0; winnt:7.0
Issue type        : kbhowto

=============================================================================

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