How store/retrieve BLOB in VB5 and SQl Server7

How store/retrieve BLOB in VB5 and SQl Server7

Post by Vincent Lo » Tue, 19 Jan 1999 04:00:00



I tried to implement by adding in RDO control , I did all the
AppendChunk() & GetChunk(), it seems no changes in SQL Server 7. No
error receive from the server.
 
 
 

1. Edit/Store/Retrieve/Submit SQL Server Blobs via XML

Hi all,

I'm looking for advices about designing a "document server"

application. I'm developing n-tiers solutions in VB and I need to

provide all my applications a way to retrieve, edit and store any

kind of documents as BLOBs in a SQL Database. These documents could

be either Word or Excel Documents, as well as large binary files or

images. I used to do that using "regular" client-server techniques

(ADO recordsets), but now that we've switched to a multi-tier

architecture, the client software does not have any mean to access

ADO methods. Following the strict rules of this architecture, my

client applications know only how to parse a XML document.

I'd like your advice about the following : I've built up a COM+ Data

Object which extracts the data from the BLOB (through a stored

procedure), saves it as XML in a stream (ADO 2.5) and sends it back

to the client as a string. On the client-side, I simply parse this

XML string and extract the "node.typedvalue" for the binary field. I

then decode it and serialize it on the local disk to let the user

access it. It works but I then face two major problems :

1) this way of proceeding is particularly slow and I don't really

see how I could improve it. The size of the XML document generated

by ADO is about twice to third bigger than the original binary file

(due to the non-binary encoding). I could rely on my own algorithms

to extract the BLOB and binary-encode it but I'm affraid it could be

even slower (?).

2) What could be the best way to do the contrary, i.e. upload a

local file to the server to store it into the database ? I was

thinking about finding a good encoding for the data before sending

it to the server as a string, but maybe it's not the most efficient

to way to proceed ?

Has anybody already done that before ? Any idea about the best

encoding / uploading techniques ? Do you see any flaw in the general

architecture I've just described ?

Thx for your helps and advices,

Olivier

2. SQL Anywhere & Delphi 2....

3. SQL Server7 linking to another SQL Server7 database.

4. BCP OUT Fixed-Length Record: Truncated Length

5. SQL Mail to SMTP Server?

6. DAO350.DLL page fault error - VB5 odbc connection to local SQL Server7

7. join indices

8. Store and Retrieve image file to and from MSSQL BLOB

9. retrieving documents stored in BLOB fields

10. How do you store / retrieve a blob?

11. Storing/Retrieving Blobs

12. storing/retrieving blobs in Access 2000