I'm pumping data from a Firebird database into a dbISAM database and ran
into a problem:

I have a picture (jpg/tif/...) in a MemoryStream and I need to put it
into a new record in a table.
Will I have to use a query like
  QRY.ParamByName(GRAPHICFIELD).LoadFromStream(STRM,ftGraphix);
I could not see such a method with
  TBL.FieldByName(GRAPHICFIELD).xxx
Is there a way using Assign ?

I have defined the field type as "Graphic" - is this ok?  Should I use
Blob (and ftBlob) or Bytes (and ft????) or something else?


dbISAM 4.22 Build 6
Delphi/2006-Pro


TiA
Aage J.

Aage

TMEMOFIELD( TBL.FieldByName(GRAPHICFIELD)).Assign


Roy Lambert

Roy Lambert wrote:
>
> TMEMOFIELD( TBL.FieldByName(GRAPHICFIELD)).Assign
>

I cannot assign a MemoryStream here, something TPersistent is required.
I tried:
  TMemoField(TBL.FieldByName('Bilde')).Assign(BILDE);
This resulted in:
  Incompatible types: 'TPersistent' and "TMemoryStream'

I had already tried:
  TBL.FieldByName('Bilde').Assign(BILDE);
with the same result.

What will I need to change?


Also, any comment on using the fieldtypes Graphic _or_ Blob?


--
Aage J.

Aage,

>   QRY.ParamByName(GRAPHICFIELD).LoadFromStream(STRM,ftGraphix);
> I could not see such a method with
>   TBL.FieldByName(GRAPHICFIELD).xxx

TBlobField(Table.FieldByName('Photo')).LoadFromStream(AStream);

> I have defined the field type as "Graphic" - is this ok?  Should I use
> Blob (and ftBlob) or Bytes (and ft????) or something else?

I would use ftBlob. ftGraphic is really just an alias for ftBlob to
support TDBImage, but that component only supports BMPs so it is no use
to you in this case anyway.

Eryk

Eryk Bottomley wrote:
> Aage,
>
>>   QRY.ParamByName(GRAPHICFIELD).LoadFromStream(STRM,ftGraphix);
>> I could not see such a method with
>>   TBL.FieldByName(GRAPHICFIELD).xxx
>
> TBlobField(Table.FieldByName('Photo')).LoadFromStream(AStream);
>
>> I have defined the field type as "Graphic" - is this ok?  Should I use
>> Blob (and ftBlob) or Bytes (and ft????) or something else?
>
> I would use ftBlob. ftGraphic is really just an alias for ftBlob to
> support TDBImage, but that component only supports BMPs so it is no use
> to you in this case anyway.
>
> Eryk


Thank you!

--
Aage J.

Aage


OK - that was me just picking up on assign in your post and going off memory

  TMemoField(TBL.FieldByName('Bilde')).LoadFromStream(BILDE);

You might have to use TGRPAHICFIELD or whatever it is - never used them always just used memo.

Roy Lambert

Aage Johansen wrote:
> Eryk Bottomley wrote:
>>
>> TBlobField(Table.FieldByName('Photo')).LoadFromStream(AStream);
>>
>>
>> I would use ftBlob. ftGraphic is really just an alias for ftBlob to
>> support TDBImage, but that component only supports BMPs so it is no
>> use to you in this case anyway.


Well.  It did work fine, BUT I ran into something else:
The table has default BLOB Block Size (512).  The pictures have an
average size of approx. 32KB.  After slightly more than 7000 records
(one picture per record) the table tried to exceed 4GB - not successful.
My test database holds 12000+ pictures, but the real one has 60.000 (and
growing).  The Firebird (test) db is about 500MB.
The pictures that got into the dbISAM table shows just fine - no evident
problems (like duplicated pictures).
I emptied the table and imported about 1000 pictures - the table was
about 280MB.

There must be something that I miss.  What?


--
Aage J.

> ...
> There must be something that I miss.  What?
>

I failed on using the MemoryStream correctly.
Sigh.
But things are looking brighter now.


--
Aage J.

Aage

> Well.  It did work fine, BUT I ran into something else:
> The table has default BLOB Block Size (512).  The pictures have an
<snip>
> I emptied the table and imported about 1000 pictures - the table was
> about 280MB.
>
> There must be something that I miss.  What?


The only thing that comes to mind is that the stream is a LOT bigger
than you think it is ...as would happen if you were decoding the JPG and
accidentally ended up grabbing it as a BMP from a TBitmap or something.

Eryk

Aage,

<< There must be something that I miss.  What? >>

Did you verify that the images were saved as JPGs in the database ?  If so,
then you should try bumping up the BLOB block size for the table to at least
1-2k.

--
Tim Young
Elevate Software
www.elevatesoft.com