We are migrating our application from 32 bit to 64 bit platform. We
are unable to connect to SqlServer via OLEDB connection string. It
works on 32 bit perfectly. Could you please provide the the guide
lines on connecting 64 bit app to the database.

Thanks
Mubashir

Which language do use? In which way to you use OLE DB? ADO? OLE DB
Consumer templates? The raw API?

Which operating system does your application run on?

--
Erland Sommarskog, SQL Server MVP, esq...@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books...
Books Online for SQL Server 2000 at
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I ran into this problem when developing a C# app and I got a new machine
with 64bit OS.  I installed everything but it no longer ran because it
couldn't connect.  Problem was that I didn't have a 64 bit version of the
OLEDB driver.

There is not difference in your application in the connection string, but
you do need to have the 64 bit version of the OLEDB drivers installed.    I
proved that to myself by writing a little code (I looked and can no longer
find it for you) to get the entire list of drivers and display them to me.  I
then ran it in 64 bit and in 32 bit modes.  I got a different list ... MUCH
shorter in 64 bit mode.

My "solution" was to change my project to force it to run in x86 (i.e. 32
bit) mode and then everything worked fine during development.  I ship both a
32bit and 64bit exe and leave it up to the customer which to use and tell
them they need to have the appropriate OLEDB providers installed to use the
64 bit version.  So far most have just run the 32bit version and been happy
with it.  Only a couple needed the extra process memory space (using HUGE
tables) and went through the trouble to get and install a 64bit provider, and
then it did work just fine.

This is one of the advantages of managed code  ... same code can run in 32
or 64 bit.

Good Luck,
Scott