Defining/Binding Blob Values

[Ivan Smahin]

Hello Thomas,

Thursday, August 14, 2008, 3:15:27 PM, you wrote:

> Hello all

> I'm using the C++-API and I'm unable to create Blob values and insert/update
> them via parameter binding (:1, :2, etc.). I have found solutions that are
> working with "DateTime" values (see source code below) and primitive data
> types (int, double, etc.) but found none for Blobs. I'm shure I'm missing
> something but I didn't find the right answer in the available valentina
> documentation.

> Here the code fragment: the problem is calling the function "put_Data" of an
> "I_ValueBinaryPtr" pointer returns always an null pointer. Is the use of
> I_ValueBinary correct in the context of blob handling? 

> Many thanks in advance and kind regards  -- Tom

> -- begin c++ - code --------------------------

> void test (void)
> {
>         //  ... valentina init ... .
>         
>         ArrayOfValues_Ptr pBinds = new ArrayOfValues();

>         // Working DateTime param binding
>         
>         struct tm dt = { 0, 0, 12, 25, 11, 99 };
>         I_Value_Ptr vdt = database->CreateValue (kTypeDateTime, fNone);
>         I_ValueDateTime_Ptr pvdt =
> fbl_dynamic_cast<I_ValueDateTime>(vdt); 
>         pvdt->put_DateTime (dt.tm_year + 1900, dt.tm_mon, dt.tm_mday,
> dt.tm_hour, 
>                                                            dt.tm_min,
> dt.tm_sec, 0);                                  
>         pBinds->AddItem (vdt);


>         // Not working Blob value binding

>         String blobData = "this is the blob data";
>         I_Value_Ptr vBlob = database->CreateValue (kTypeBLOB, fNone);
>         I_ValueBinary_Ptr pvbBlob =
> fbl_dynamic_cast<I_ValueBinary>(vBlob);

>         // --> Makes pBlob a null pointer 
>         pvbBlob->put_Data ((uchar*)blobData.getBuffer(), blobData.length());


>         // --> Throws an exception because pBlob is null.
>         pBinds->AddItem (vBlob);

>         // ... query execution  ...  e.g. "insert into table (fldDayTime,
> fldBlob) 
>         //                                 values (:1, :2)" ...
> }
> -- end c++ - code --------------------------

You should use kTypeFixedBinary instead of kTypeBLOB for vBlob value.
I_Value_Ptr vBlob = database->CreateValue (kTypeFixedBinary, fNone);
-- 
Best regards,
Ivan Smahin 
Senior Software Engineer
Paradigma Software, Inc
Valentina - The Ultra-Fast Database
http://www.valentina-db.com