3.0->3.1 client question

[Ivan Smahin]

Hello Thorsten,

Monday, July 2, 2007, 11:31:39 AM, you wrote:

> Hi,

> On 2007-07-02, at 10:16, Barry G. Sumpter wrote:

>> Any VDB v3.0 opened with any v3.1 kernel will update the database.
>> Not just VS.  i.e. thru code as well.
>>
>> BOTH VDK 3.1 AND VSTUDIO 3.1 are available for download.

> What happened if a deployed server is running on a VServer 3.0.x and  
> a REALbasic-Client connected to it, where  V4RB 3.1 is used?  
> Especially when I don't want or better don't be able to update the  
> server but want to provide the new client for newly installed 3.1  
> VServer.

No, you can't use 3.1 VClient against 3.0.x VServer and vice versa.
Starting from 3.1 passwords are sent as MD5 digests.
But  note, it fixes VClient-VServer communication - it does not depend
on the VKernel.

Well,  generally,  VClient  component  does not depend on VKernel
issues  at  all. Using VClient you call some special implementations of
database public interfaces ("pass" call info throw network to the
server  which, in turn, works with VKernel).
So VClient compatibility is defined by ability of VServer
to receive packets of particular version only.

Generally there are 3 cases when VClient becomes incompatible with early VServer
versions:

1.  Some  interface  changes are introduced. (We know, it is not good practice
but possible scenario)
2. Optimization issues in  VClient which requires to change format of
packets.
3. VClient bug fixing may require to change packet structure.

Also,  note, we are supporting "partly-incompatibility" wherever it is
possible.  I  mean  -  you can use new VClient against old VServer or
otherwise till you don't get into incompatible  area.

Logon  procedure  is  most  common  place,  so  VClient version 3.1 is
"fully-incompatible" with early versions.





-- 
Best regards,
Ivan Smahin 
Senior Software Engineer
Paradigma Software, Inc
Valentina - The Ultra-Fast Database
http://www.valentina-db.com