Blob field save AsString into DB

[question]

Hi,
I have a Bolb field 'CollectID' in the DB and i am saving the data into this Blob Field AsString in the following way,

Code:

QueryA.ParamByName('CollectID').AsString := QueryB.FieldByName('CollectID').AsString;

its working fine,but i am not sure is that okay or it can be problem in future

[Perlsau]

What does this blob field represent? If you would fill a TMemo or a TRichEdit with the contents of this blob field, it would be okay. But if you want do represent a picture, a wave form or something like this it could be a problem to write/read it as string. Normally you read and write blob data by TFileStream or TMemoryStream:

Delphi-Quellcode:

function TDatMod.File_To_Blob(FileName: String; BlobFeld: TField): Boolean;
VAR
   S         : TStream;
   FileS     : TFileStream;

begin
     Result := FALSE;
     IF NOT FileExists(FileName) THEN EXIT;

     S      := BlobFeld.DataSet.CreateBlobStream(BlobFeld, bmReadWrite);
     TRY
        FileS  := TFileStream.Create(FileName, fmOpenRead);
        S.CopyFrom(FileS, FileS.Size);
        Result := TRUE;
     FINALLY
        FileS.Free;
        S.Free;
     END;
end;

function TDatMod.Blob_To_File(FileName: String; BlobFeld: TField): Boolean;
VAR
   S         : TStream;
   FileS     : TFileStream;

begin
     Result := FALSE;
     IF BlobFeld.IsNull THEN EXIT;

     S := BlobFeld.DataSet.CreateBlobStream(BlobFeld, bmRead);
     TRY
        FileS := TFileStream.Create(FileName, fmCreate);
        FileS.CopyFrom(S, S.Size);
        Result   := TRUE;
     FINALLY
        S.Free;
        FileS.Free;
     END;
end;

[question]

it does not fill picture, it filled with binary text, in this situtation, is that okay to use it

Code:

QueryA.ParamByName('CollectID').AsString := QueryB.FieldByName('CollectID').AsString;

by the way, i have another problem, i have reinstalled the database and now the Blob field is not working in the whole application,dont know why,have you any suggestion?

[DeddyH]

Is the BLOB-field accessable using an administration-tool? If not, it is quite senseless to try to access it by your application and search for errors there.

[question]

Hi,
thanks for your important information
but there is no administration-tool to access the BLOB-field
in this situation,how can i overcome this problem?

[DeddyH]

Most administration-tools I know offer several options for BLOB-fields such as "view as text" or "view as picture". Maybe you have to search for them a little bit.

[mkinzler]

initiative of his/her own isn't questions kind. Thus he/she doesn't even try to understand answers and insits on his/her pov.

http://www.delphipraxis.net/176416-d...-new-post.html

@question If your solution works than be happy. We tried to told you several times that a blob isn't a normal field, and when you refuse to recognize it and not using an better solution than your easier but maybe buggy version, than do it on your own responsibility!