Главная страница
Top.Mail.Ru    Яндекс.Метрика
Текущий архив: 2008.06.29;
Скачать: CL | DM;

Вниз

Database large object   Найти похожие ветки 

 
Jon ©   (2007-09-24 02:49) [0]

With KOLEdb to get FieldByNameAsHex how can I find the size of the returned data in bytes? (I have image stored or binary data)


 
thaddy   (2007-09-24 03:05) [1]

Use a memorystream and use memorystream.size ;-)


 
Jon ©   (2007-09-24 12:14) [2]

That is what I though but I cannot get the data into the stream.
This is the code that I am trying:

var
 Stream: PStream;
 Blob: Pointer;
 QR: PQuery;
begin
 ...
 Stream := NewMemoryStream;
 try
   Blob := QR.FieldByNameAsHex["picblob"];  // Stream.Write requires var parameter
   Stream.Write(Blob,????);   // Write(var Buffer; Count: DWord)
   Stream.SaveToFile("c:\blob.bin",0,Stream.Size);
 finally
   Stream.Free;
 end;
end;

I think that I am not understanding the technique correctly.
Is there a working example to help me please? Thank you.


 
Vladimir Kladov ©   (2007-09-24 18:09) [3]

I did not implement blobs in KOLEDb. Certainly this may be possible but changing code (may be a lot). It seems that this is not necessary for new DB engines like MS SQL 2000 / XP: there are no more restrictions for varchar field maximum size as earlier.


 
Jon ©   (2007-09-24 18:37) [4]

Thanks - I am glad that it is KOLEDb and not me.

I think that adding blob support would be very useful.

MySQL VARCHAR max length is 255 before MySQL 5.0.3, and 65535 in 5.0.3 and later versions.

I shall try to hack KOLEDb, unless another method is recommended.



Страницы: 1 вся ветка

Текущий архив: 2008.06.29;
Скачать: CL | DM;

Наверх




Память: 0.47 MB
Время: 0.02 c
2-1212223941
Pi:=3.14...
2008-05-31 12:52
2008.06.29
Код в программе


15-1210843226
User1
2008-05-15 13:20
2008.06.29
Приложения написанные на Delphi


15-1210838747
Игорь М.
2008-05-15 12:05
2008.06.29
проблемы с видеотображением


15-1210775089
Vlad Oshin
2008-05-14 18:24
2008.06.29
Впервые в команде. Думал, прикалываетесь.


3-1201071521
O.O
2008-01-23 09:58
2008.06.29
Изменение вычисляемого поля