Are your referring to the modification date as given by the file system, only the modification date as shown by digikam, or both?
In other words, is the problem that the modification date of the file is changed but this is not found by digikam, or is the problem that the modification date of the file is (intentionally) not changed when adjusting the metadata?

I am talking about the Modification date as shown by Digikam. I have not checked what the filesystem says yet.

Note: this is somewhat related to situation where indexable file doesn't have EXIF data. In such situations modification date (system date) which is usually real creation date may be earlier than digiKam creation date because in such situation digiKam takes for creation date date of import to database. Related fragments of mails from digikam-users:


Thomas (tzsnoopy):
since a few days I am using digiKam 0.10.0 and I have to say it is a
great piece of software!!
But now I am a bit confused about the dates shown in digiKam.

In the thumbnail view there are shown two dates below each image, the
creation date as well as the modification date. For all of my pictures
containing EXIF data the dates are like I would expect. But for movies
as well as images without EXIF data it's a bit confusing. There, the
modified date matches the date the movie was taken, but the creation
date seems to be not really related to the file. The sad thing for me is
that the creation date is used for the timeline and thus all my movies
appear at the wrong date.

Here an example:
PICT0003.mov
created: 12.08.2008 (I have no idea what I did with the file on this
day)
modified: 16.05.2004  (on this day the movie was taken)

The strange thing is that the date shown as "created" is not equal to
the mtime, ctime, or utime of the file (according to "ls -l", "ls -lc",
and "ls -lu").

So finally, here are my questions: 
- Where does the date that is taken as the creation date by digiKam come
from?
- And, is there any possibility to replace the date stored as "created"
by the date stored as "modified"? I have several hundred images and
movies without EXIF data, so adjusting the date for each image by hand
using the menu is not a real option.
------------------------------------------------------
And his final solution:

Still, I do not know where digikam gets the creation date from if there
is no metadata in the file. 
But "database" was a good hint. I could take the modifications dates
(which are in my case the real dates of taking the movies) and set them
as creation dates by directly modifying the digikam database.

For all people with a similar problem, here is the way I did it:
I opened the digikam database file (in my case: digikam4.db), which is a
sqlite database, with sqliteadmin running under wine. There I performed
the following SQL query:

UPDATE ImageInformation
SET creationDate = (SELECT Images.modificationDate FROM Images WHERE
ImageInformation.imageid = Images.id)
WHERE digitizationDate is null

The "WHERE digitizationDate is null" is used to adjust the creation date
only of those files without metadata.

For me this query worked fine. But of course someone should only try
this if he/she knows what this stuff is doing. Adapting the digikam
database directly could destroy it! So always make a backup before.
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Dotan: Modification date is the file system's modification date, nothing else. It is always in sync with the file system info. There is an option in digikam "Update file timestamp when metadata is saved" if the modification date shall be changed when changing metadata (normally is should, but people think changing metadata doesn't qualify as changes). The modification date is then changed to the date when you do the change, not the date you adjust the creation time to.
It may be possible to fool the filesystem info and adjust the modification date as well. So this is either a WISH or a WONTFIX.

Mikolaj: I think this bug has been fixed recently. We now use the oldest of ctime, mtime.

Dotan,

This file still valid using kipi-plugins 2.4 ?

Gilles Caulier

Modified file date is already managed by this tool...

Gilles Caulier