diff --git a/etiquette/constants.py b/etiquette/constants.py
index a42ee70..46e7e84 100644
--- a/etiquette/constants.py
+++ b/etiquette/constants.py
@@ -41,7 +41,7 @@ ffmpeg = _load_ffmpeg()
 
 # Database #########################################################################################
 
-DATABASE_VERSION = 22
+DATABASE_VERSION = 23
 
 DB_INIT = f'''
 CREATE TABLE IF NOT EXISTS albums(
@@ -135,6 +135,7 @@ CREATE INDEX IF NOT EXISTS index_users_username on users(username COLLATE NOCASE
 CREATE TABLE IF NOT EXISTS album_associated_directories(
     albumid INT NOT NULL,
     directory TEXT NOT NULL COLLATE NOCASE,
+    created INT,
     FOREIGN KEY(albumid) REFERENCES albums(id)
 );
 CREATE INDEX IF NOT EXISTS index_album_associated_directories_albumid on
@@ -145,6 +146,8 @@ CREATE INDEX IF NOT EXISTS index_album_associated_directories_directory on
 CREATE TABLE IF NOT EXISTS album_group_rel(
     parentid INT NOT NULL,
     memberid INT NOT NULL,
+    created INT,
+    PRIMARY KEY(parentid, memberid),
     FOREIGN KEY(parentid) REFERENCES albums(id),
     FOREIGN KEY(memberid) REFERENCES albums(id)
 );
@@ -154,20 +157,19 @@ CREATE INDEX IF NOT EXISTS index_album_group_rel_memberid on album_group_rel(mem
 CREATE TABLE IF NOT EXISTS album_photo_rel(
     albumid INT NOT NULL,
     photoid INT NOT NULL,
+    created INT,
+    PRIMARY KEY(albumid, photoid),
     FOREIGN KEY(albumid) REFERENCES albums(id),
     FOREIGN KEY(photoid) REFERENCES photos(id)
 );
 CREATE INDEX IF NOT EXISTS index_album_photo_rel_albumid on album_photo_rel(albumid);
 CREATE INDEX IF NOT EXISTS index_album_photo_rel_photoid on album_photo_rel(photoid);
 ----------------------------------------------------------------------------------------------------
-CREATE TABLE IF NOT EXISTS id_numbers(
-    tab TEXT NOT NULL,
-    last_id TEXT NOT NULL
-);
-----------------------------------------------------------------------------------------------------
 CREATE TABLE IF NOT EXISTS photo_tag_rel(
     photoid INT NOT NULL,
     tagid INT NOT NULL,
+    created INT,
+    PRIMARY KEY(photoid, tagid),
     FOREIGN KEY(photoid) REFERENCES photos(id),
     FOREIGN KEY(tagid) REFERENCES tags(id)
 );
@@ -178,6 +180,8 @@ CREATE INDEX IF NOT EXISTS index_photo_tag_rel_photoid_tagid on photo_tag_rel(ph
 CREATE TABLE IF NOT EXISTS tag_group_rel(
     parentid INT NOT NULL,
     memberid INT NOT NULL,
+    created INT,
+    PRIMARY KEY(parentid, memberid),
     FOREIGN KEY(parentid) REFERENCES tags(id),
     FOREIGN KEY(memberid) REFERENCES tags(id)
 );
@@ -186,7 +190,8 @@ CREATE INDEX IF NOT EXISTS index_tag_group_rel_memberid on tag_group_rel(memberi
 ----------------------------------------------------------------------------------------------------
 CREATE TABLE IF NOT EXISTS tag_synonyms(
     name TEXT NOT NULL,
-    mastername TEXT NOT NULL
+    mastername TEXT NOT NULL,
+    created INT
 );
 CREATE INDEX IF NOT EXISTS index_tag_synonyms_name on tag_synonyms(name);
 '''
diff --git a/etiquette/objects.py b/etiquette/objects.py
index e3af592..43b1e59 100644
--- a/etiquette/objects.py
+++ b/etiquette/objects.py
@@ -122,6 +122,7 @@ class GroupableMixin(metaclass=abc.ABCMeta):
         data = {
             'parentid': self.id,
             'memberid': member.id,
+            'created': helpers.now().timestamp(),
         }
         self.photodb.insert(table=self.group_table, pairs=data)
 
@@ -332,7 +333,11 @@ class Album(ObjectBase, GroupableMixin):
             return
 
         log.info('Adding directory "%s" to %s.', path.absolute_path, self)
-        data = {'albumid': self.id, 'directory': path.absolute_path}
+        data = {
+            'albumid': self.id,
+            'directory': path.absolute_path,
+            'created': helpers.now().timestamp(),
+        }
         self.photodb.insert(table='album_associated_directories', pairs=data)
 
     @decorators.required_feature('album.edit')
@@ -375,7 +380,11 @@ class Album(ObjectBase, GroupableMixin):
 
     def _add_photo(self, photo):
         log.info('Adding photo %s to %s.', photo, self)
-        data = {'albumid': self.id, 'photoid': photo.id}
+        data = {
+            'albumid': self.id,
+            'photoid': photo.id,
+            'created': helpers.now().timestamp(),
+        }
         self.photodb.insert(table='album_photo_rel', pairs=data)
 
     @decorators.required_feature('album.edit')
@@ -965,7 +974,8 @@ class Photo(ObjectBase):
 
         data = {
             'photoid': self.id,
-            'tagid': tag.id
+            'tagid': tag.id,
+            'created': helpers.now().timestamp(),
         }
         self.photodb.insert(table='photo_tag_rel', pairs=data)
         data = {
@@ -1661,6 +1671,7 @@ class Tag(ObjectBase, GroupableMixin):
         data = {
             'name': synname,
             'mastername': self.name,
+            'created': helpers.now().timestamp(),
         }
         self.photodb.insert(table='tag_synonyms', pairs=data)
 
diff --git a/utilities/database_upgrader.py b/utilities/database_upgrader.py
index 7dce720..2f20bb3 100644
--- a/utilities/database_upgrader.py
+++ b/utilities/database_upgrader.py
@@ -888,6 +888,117 @@ def upgrade_21_to_22(photodb):
     photodb.execute('DROP INDEX IF EXISTS index_photos_override_filename')
     photodb.execute('CREATE INDEX IF NOT EXISTS index_photos_basename on photos(basename COLLATE NOCASE)')
 
+def upgrade_22_to_23(photodb):
+    '''
+    In this version, the rel tables received explicit primary keys and
+    a `created` column.
+    '''
+    m = Migrator(photodb)
+
+    m.tables['album_associated_directories']['create'] = '''
+    CREATE TABLE IF NOT EXISTS album_associated_directories(
+        albumid INT NOT NULL,
+        directory TEXT NOT NULL COLLATE NOCASE,
+        created INT,
+        FOREIGN KEY(albumid) REFERENCES albums(id)
+    );
+    '''
+    m.tables['album_associated_directories']['transfer'] = '''
+    INSERT INTO album_associated_directories SELECT
+        albumid,
+        directory,
+        (SELECT created FROM albums WHERE id=albumid)
+    FROM album_associated_directories_old;
+    '''
+
+    m.tables['album_group_rel']['create'] = '''
+    CREATE TABLE IF NOT EXISTS album_group_rel(
+        parentid INT NOT NULL,
+        memberid INT NOT NULL,
+        created INT,
+        PRIMARY KEY(parentid, memberid),
+        FOREIGN KEY(parentid) REFERENCES albums(id),
+        FOREIGN KEY(memberid) REFERENCES albums(id)
+    );
+    '''
+    m.tables['album_group_rel']['transfer'] = '''
+    INSERT INTO album_group_rel SELECT
+        parentid,
+        memberid,
+        MAX((SELECT created FROM albums WHERE id=parentid), (SELECT created FROM albums WHERE id=memberid))
+    FROM album_group_rel_old;
+    '''
+
+    m.tables['album_photo_rel']['create'] = '''
+    CREATE TABLE IF NOT EXISTS album_photo_rel(
+        albumid INT NOT NULL,
+        photoid INT NOT NULL,
+        created INT,
+        PRIMARY KEY(albumid, photoid),
+        FOREIGN KEY(albumid) REFERENCES albums(id),
+        FOREIGN KEY(photoid) REFERENCES photos(id)
+    );
+    '''
+    m.tables['album_photo_rel']['transfer'] = '''
+    INSERT INTO album_photo_rel SELECT
+        albumid,
+        photoid,
+        MAX((SELECT created FROM albums WHERE id=albumid), (SELECT created FROM photos WHERE id=photoid))
+    FROM album_photo_rel_old;
+    '''
+
+    m.tables['photo_tag_rel']['create'] = '''
+    CREATE TABLE IF NOT EXISTS photo_tag_rel(
+        photoid INT NOT NULL,
+        tagid INT NOT NULL,
+        created INT,
+        PRIMARY KEY(photoid, tagid),
+        FOREIGN KEY(photoid) REFERENCES photos(id),
+        FOREIGN KEY(tagid) REFERENCES tags(id)
+    );
+    '''
+    m.tables['photo_tag_rel']['transfer'] = '''
+    INSERT INTO photo_tag_rel SELECT
+        photoid,
+        tagid,
+        MAX((SELECT created FROM photos WHERE id=photoid), (SELECT created FROM tags WHERE id=tagid))
+    FROM photo_tag_rel_old;
+    '''
+
+    m.tables['tag_group_rel']['create'] = '''
+    CREATE TABLE IF NOT EXISTS tag_group_rel(
+        parentid INT NOT NULL,
+        memberid INT NOT NULL,
+        created INT,
+        PRIMARY KEY(parentid, memberid),
+        FOREIGN KEY(parentid) REFERENCES tags(id),
+        FOREIGN KEY(memberid) REFERENCES tags(id)
+    );
+    '''
+    m.tables['tag_group_rel']['transfer'] = '''
+    INSERT INTO tag_group_rel SELECT
+        parentid,
+        memberid,
+        MAX((SELECT created FROM tags WHERE id=parentid), (SELECT created FROM tags WHERE id=memberid))
+    FROM tag_group_rel_old;
+    '''
+
+    m.tables['tag_synonyms']['create'] = '''
+    CREATE TABLE IF NOT EXISTS tag_synonyms(
+        name TEXT NOT NULL,
+        mastername TEXT NOT NULL,
+        created INT
+    );
+    '''
+    m.tables['tag_synonyms']['transfer'] = '''
+    INSERT INTO tag_synonyms SELECT
+        name,
+        mastername,
+        (SELECT COALESCE(created, 0) FROM tags WHERE tags.name=name)
+    FROM tag_synonyms_old;
+    '''
+    m.go()
+
 def upgrade_all(data_directory):
     '''
     Given the directory containing a phototagger database, apply all of the