Old Problem: saving images by SQL. Save and read it again. It is found that the stream size is inconsistent. Although old, no results are found.

Old Problem: saving images by SQL. Save and read it again. It is found that the stream size is inconsistent. Although old, no results are found. Delphi/Windows SDK/API
Http://www.delphi2007.net/DelphiDB/html/delphi_20061217121231255.html
Tclientdataset
Save as follows
VaR
Tempclient: tclientdataset;
Tempjpeg: tsf-image;
Tempstream: tmemorystream;
....
Begin
....
Tempjpeg. loadfromfile ('d: \ 1.jpg ');
Tempjpeg. savetostream (tempstream );
Tempclient. commandtext: = 'insert into mytest (imageid, imagesize, image) values (: ID,: Size,: imagedata )';
Tempclient. Params. parambyname ('id'). asinteger: = tempid;
Tempclient. Params. parambyname ('SIZE'). asinteger: = tempstream. size;
Tempclient. Params. parambyname ('imagedata'). loadfromstream (tempstream, ftgraphic );
// The size of the corresponding streaming is the same as that of 1.jpg. The stream size is 447244
Tempclient. Execute;
....
End;

Read
VaR
Tempclient: tclientdataset;
Begin
Tempclient: = tclientdataset. Create (NiL );
Try
Tempclient. commandtext: = 'select imagesize, image from mytest where id = 1 ';
Tempclient. open;
If not tempclient. fieldbyname ('image'). isnull then
Begin
Tblobfield (tempclient. fieldbyname ('image'). savetostream (tempstream );
// The size of the tempsteam file I read is different from that of the original JPEG file. Save the stream to a file and find that the data is not correct at all. The size of the original file is 447244, and the size of the stream obtained from the database is 550262.
End;
Fianlly
...
End;
End;

The database is SQL 2000 and uses ADO connection.

Try to save and read them directly.
Tempclient. Params. parambyname ('imagedata'). loadfromfile ('d: \ 1.jpg ');

Tblobfield (tempclient. fieldbyname ('image'). savetofile ('d: \ 1.jpg ');

Thank you.

The result of returning xxmmmx (kicking) () Direct loadfromefile is the same as that of savetofile.
The new files saved by the savetofile are still larger. Data also changed

I tested it. No problem. However, I use adoquery;

VaR
Tempjpeg: tsf-image;
Tempstream: tmemorystream;
Begin
Tempstream: = tmemorystream. Create;
Tempjpeg: = tsf-image. Create;
Tempjpeg. loadfromfile ('C: \ 1.jpg '); // the size of the original file is 148884 bytes.
Tempjpeg. savetostream (tempstream );
Showmessage (floattostr (tempstream. Size); // 148884 bytes
Tempquery. SQL. Text: = 'insert into timage (imagesize, image) values (: Size,: imagedata )';
Tempquery. Parameters. parambyname ('SIZE'). Value: = tempstream. size;
Tempquery. Parameters. parambyname ('imagedata'). loadfromstream (tempstream, ftgraphic );
Tempquery. execsql;
End;

Procedure tformdemo. bexportclick (Sender: tobject );
VaR
Tempjpeg: tsf-image;
Tempstream: tmemorystream;
Begin
Tempstream: = tmemorystream. Create;
Tempquery. SQL. Text: = 'select image from timage where imageid = 1 ';
Tempquery. open;
Tblobfield (tempquery. fieldbyname ('image'). savetostream (tempstream );
Showmessage (floattostr (tempstream. Size); // 148884 bytes
End;

In addition, I tested the xxmmmx recommendation.

Write
Tempquery. Parameters. parambyname ('imagedata'). loadfromfile ('C: \ 1. jpg ', ftblob );

Read
Tblobfield (tempquery. fieldbyname ('image'). savetofile ('C: \ 2. jpg ');

The results are exactly the same. ('C: \ 1. jpg 'and 'C: \ 2. jpg' are exactly the same)

You can use tclientdataset.
I use tclientdataset.

Is tclientdataset not supported? Tclientdataset is used in the project. Dizzy.

It's okay if I use it like this.
Ado + datasetprovider + tclientdataset

For example:
Save
If cdserfiles. isempty then
Begin
Cdserfiles. append;
Cdserfiles. fieldbyname ('recid'). asstring: = trim (owexaminerepairid. Text );
Cdserfiles. fieldbyname ('state'). asinteger: = 0;
Cdserfiles. fieldbyname ('type'). asinteger: = 0;
End else
Cdserfiles. Edit;
Cdserfiles. fieldbyname ('filename'). asstring: = extractfilename (opendialog. filename );
Tblobfield (cdserfiles. fieldbyname ('filecontent'). loadfromfile (opendialog. filename );

Cdserfiles. applyupdates (0 );

Read and save as a file:
Sfilename: = sfilename + '\' + cdserfiles. fieldbyname ('filename'). asstring;

Tblobfield (cdserfiles. fieldbyname ('filecontent'). savetofile (sfilename );
If fileexists (sfilename) then
ShellExecute (handle, 'open', pchar (sfilename), nil, nil, sw_shownormal)