Blob in C++ Valentina ADK

[Ruslan Zasukhin]

On 7/3/13 4:58 PM, "Leo van Rijswijk" <leov at qmatix.com> wrote:

> Hi Ruslan
>  
> Thanks, yes I still need the help on yesterdays email.
>  
> While waiting for that I have begun setting up a test for blobsŠ
> Documentation is not always easy as I found VBLOB, but without sample code not
> simple to find the c++ equivalents.

Our WIKI's  API  Reference for ADKs  is targeted all rest languages except
C++


For C++ developers we very hope on ability to read headers :)

Major point is:  learn    publ/Interaces  folder,
 all this are entry points.



==========
About BLOBs

Very important to understand for Valentina

* BLOB is mostly unlimited by size

* SegmentSize of BLOB field defines just segment size,
 but can be many segments in one blob value.

* size of segment should be from 128 bytes and more ...

* it should be in ideal near to AVERAGE size of blob values in THIS column.

* different columns can have different segment sizes


* Valentina keep blob as 2 fileds:

   1)  ULONG column in table itself
   2) SegmentFile that keep that segments with blob values.

ULONG column keep pointer to the first segment


So it is obvious that when you go to some record in table

   table.RecID = xx

Blob value is NOT loaded
Only   

  blob->ReadData() 

Will load it from disk






-- 
Best regards,

Ruslan Zasukhin
VP Engineering and New Technology
Paradigma Software, Inc

Valentina - Joining Worlds of Information
http://www.paradigmasoft.com

[I feel the need: the need for speed]