🚀 go-pugleaf

"Chemile" <chemile@qwest.net> wrote in message
news:40fd95b4$1@newsgroups.borland.com...
> I've been trying to figure out how to read from a varbinary field
for quite
> some time without any luck.  Some of the symbols return as question
marks.
> I'm using Borload C++ Builder 6 and ADO components.  I did figure
out how to
> update a field in hexadecimal.
>
>     pQuery->Close();
>     pQuery->SQL->Clear();
>     pQuery->SQL->Add("insert into tablename (key,binfield) values
> ('1',0x"+hexVal+")");
>     pQuery->ExecSQL();
>
> I also figured a way around it that worked for a while.  I used
"IdHTTP1" to
> download a php webpage that returned the fields data.  But once a
field got
> larger then 256 bytes that stopped working.
>
> I've heard that blobs do not work with varbinary fields.  I'm not
sure if
> that is true, but I haven't been able to retrieve it as a blob.
>
> TADOBlobStream *Stream = new
> TADOBlobStream((TBlobField*)pQuery->Fields->Fields[0],bmRead);
>
> Is there a way to return a query in hexadecimal or in a stream so
that
> extended character info is saved?  Should I change components?
>
> Thanks

We read and write SQL Server VARBINARY and Oracle BLOB fields with the
same routines.  See below.

// Read a VARBINARY or BLOB.  The TADOQuery has been opened.
AnsiString varBin = q->FieldByName( "VarBinField" )->AsString;
// varBin.Length() is how many bytes were read.  Now, do whatever you
want with it.

// Write -
// The SQL is: "INSERT INTO ATable (VarBinField ) VALUES ( :vb )"
   TMemoryStream *MS = new TMemoryStream;
   MS->Write( myBlob, sizeof(myBlob) );
   MS->Seek( 0, soFromBeginning );
   q->Parameters->Items[0]->LoadFromStream( MS, ftBlob );
   delete MS;

I'm sure there are many other, possibly better ways of doing it.

HTH
- Arnie