Add a column that shows the date when the metadata of a book record was alst modified in calibre. To see the column, right click on the column headers in calibre and select Show column->Modified

resources/default_tweaks.py

@@ -118,6 +118,7 @@ sort_columns_at_startup = None
 # timestamp default if not set: dd MMM yyyy
 gui_pubdate_display_format = 'MMM yyyy'
 gui_timestamp_display_format = 'dd MMM yyyy'
+gui_last_modified_display_format = 'dd MMM yyyy'
 
 #: Control sorting of titles and series in the library display
 # Control title and series sorting in the library view. If set to

src/calibre/gui2/library/delegates.py

@@ -97,18 +97,25 @@ class RatingDelegate(QStyledItemDelegate): # {{{
 
 class DateDelegate(QStyledItemDelegate): # {{{
 
+    def __init__(self, parent, tweak_name='gui_timestamp_display_format',
+            default_format='dd MMM yyyy', editor_format='dd MMM yyyy'):
+        QStyledItemDelegate.__init__(self, parent)
+        self.tweak_name = tweak_name
+        self.default_format = default_format
+        self.editor_format = editor_format
+
     def displayText(self, val, locale):
         d = val.toDate()
         if d <= UNDEFINED_QDATE:
             return ''
-        format = tweaks['gui_timestamp_display_format']
+        format = tweaks[self.tweak_name]
         if format is None:
-            format = 'dd MMM yyyy'
+            format = self.default_format
         return format_date(d.toPyDate(), format)
 
     def createEditor(self, parent, option, index):
         qde = QStyledItemDelegate.createEditor(self, parent, option, index)
-        qde.setDisplayFormat('dd MMM yyyy')
+        qde.setDisplayFormat(self.editor_format)
         qde.setMinimumDate(UNDEFINED_QDATE)
         qde.setSpecialValueText(_('Undefined'))
         qde.setCalendarPopup(True)

src/calibre/gui2/library/models.py

@@ -70,6 +70,7 @@ class BooksModel(QAbstractTableModel): # {{{
                         'publisher' : _("Publisher"),
                         'tags'      : _("Tags"),
                         'series'    : _("Series"),
+                        'last_modified' : _('Modified'),
     }
 
     def __init__(self, parent=None, buffer=40):
@@ -620,6 +621,8 @@ class BooksModel(QAbstractTableModel): # {{{
                                 idx=self.db.field_metadata['timestamp']['rec_index']),
                    'pubdate'  : functools.partial(datetime_type,
                                 idx=self.db.field_metadata['pubdate']['rec_index']),
+                   'last_modified': functools.partial(datetime_type,
+                                idx=self.db.field_metadata['last_modified']['rec_index']),
                    'rating'   : functools.partial(rating_type,
                                 idx=self.db.field_metadata['rating']['rec_index']),
                    'publisher': functools.partial(text_type,

src/calibre/gui2/library/views.py

@@ -76,6 +76,8 @@ class BooksView(QTableView): # {{{
         self.rating_delegate = RatingDelegate(self)
         self.timestamp_delegate = DateDelegate(self)
         self.pubdate_delegate = PubDateDelegate(self)
+        self.last_modified_delegate = DateDelegate(self,
+                tweak_name='gui_last_modified_display_format')
         self.tags_delegate = CompleteDelegate(self, ',', 'all_tags')
         self.authors_delegate = CompleteDelegate(self, '&', 'all_author_names', True)
         self.cc_names_delegate = CompleteDelegate(self, '&', 'all_custom', True)
@@ -296,6 +298,7 @@ class BooksView(QTableView): # {{{
         state = {}
         state['hidden_columns'] = [cm[i] for i in  range(h.count())
                 if h.isSectionHidden(i) and cm[i] != 'ondevice']
+        state['last_modified_injected'] = True
         state['sort_history'] = \
             self.cleanup_sort_history(self.model().sort_history)
         state['column_positions'] = {}
@@ -380,7 +383,7 @@ class BooksView(QTableView): # {{{
 
     def get_default_state(self):
         old_state = {
-                'hidden_columns': [],
+                'hidden_columns': ['last_modified'],
                 'sort_history':[DEFAULT_SORT],
                 'column_positions': {},
                 'column_sizes': {},
@@ -388,6 +391,7 @@ class BooksView(QTableView): # {{{
                     'size':'center',
                     'timestamp':'center',
                     'pubdate':'center'},
+                'last_modified_injected': True,
                 }
         h = self.column_header
         cm = self.column_map
@@ -398,7 +402,7 @@ class BooksView(QTableView): # {{{
                 old_state['column_sizes'][name] = \
                     min(350, max(self.sizeHintForColumn(i),
                         h.sectionSizeHint(i)))
-                if name == 'timestamp':
+                if name in ('timestamp', 'last_modified'):
                     old_state['column_sizes'][name] += 12
         return old_state
 
@@ -418,6 +422,13 @@ class BooksView(QTableView): # {{{
                         pass
                     if ans is not None:
                         db.prefs[name] = ans
+                else:
+                    if not ans.get('last_modified_injected', False):
+                        ans['last_modified_injected'] = True
+                        hc = ans.get('hidden_columns', [])
+                        if 'last_modified' not in hc:
+                            hc.append('last_modified')
+                        db.prefs[name] = ans
         return ans
 
 
@@ -459,7 +470,8 @@ class BooksView(QTableView): # {{{
     def database_changed(self, db):
         for i in range(self.model().columnCount(None)):
             if self.itemDelegateForColumn(i) in (self.rating_delegate,
-                    self.timestamp_delegate, self.pubdate_delegate):
+                    self.timestamp_delegate, self.pubdate_delegate,
+                    self.last_modified_delegate):
                 self.setItemDelegateForColumn(i, self.itemDelegate())
 
         cm = self.column_map

src/calibre/gui2/preferences/create_custom_column.py

@@ -63,7 +63,7 @@ class CreateCustomColumn(QDialog, Ui_QCreateCustomColumn):
         self.shortcuts.linkActivated.connect(self.shortcut_activated)
         text = '<p>'+_('Quick create:')
         for col, name in [('isbn', _('ISBN')), ('formats', _('Formats')),
-                ('last_modified', _('Modified Date')), ('yesno', _('Yes/No')),
+                ('yesno', _('Yes/No')),
                 ('tags', _('Tags')), ('series', _('Series')), ('rating',
                     _('Rating')), ('people', _("People's names"))]:
             text += ' <a href="col:%s">%s</a>,'%(col, name)
@@ -150,7 +150,6 @@ class CreateCustomColumn(QDialog, Ui_QCreateCustomColumn):
             'tags': _('My Tags'),
             'series': _('My Series'),
             'rating': _('My Rating'),
-            'last_modified':_('Modified Date'),
             'people': _('People')}[which])
         self.is_names.setChecked(which == 'people')
         if self.composite_box.isVisible():
@@ -158,9 +157,8 @@ class CreateCustomColumn(QDialog, Ui_QCreateCustomColumn):
                 {
                     'isbn': '{identifiers:select(isbn)}',
                     'formats': '{formats}',
-                    'last_modified':'''{last_modified:'format_date($, "dd MMM yyyy")'}'''
                     }[which])
-            self.composite_sort_by.setCurrentIndex(2 if which == 'last_modified' else 0)
+            self.composite_sort_by.setCurrentIndex(0)
 
     def datatype_changed(self, *args):
         try: