diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index 9d58ae4456..89184bedf9 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -3217,7 +3217,6 @@ books_series_link      feeds
             if callable(callback):
                 if callback(''):
                     break
-
         return duplicates
 
     def add_custom_book_data(self, book_id, name, val):
@@ -3226,12 +3225,19 @@ books_series_link      feeds
             raise ValueError('add_custom_book_data: no such book_id %d'%book_id)
         # Do the json encode first, in case it throws an exception
         s = json.dumps(val, default=to_json)
-        self.conn.execute('DELETE FROM books_plugin_data WHERE book=? AND name=?',
-                          (book_id, name))
-        self.conn.execute('''INSERT INTO books_plugin_data(book, name, val)
+        self.conn.execute('''INSERT OR REPLACE INTO books_plugin_data(book, name, val)
                              VALUES(?, ?, ?)''', (book_id, name, s))
         self.commit()
 
+    def add_multiple_custom_book_data(self, name, vals, delete_first=False):
+        if delete_first:
+            self.conn.execute('DELETE FROM books_plugin_data WHERE name=?', (name, ))
+        self.conn.executemany(
+            'INSERT OR REPLACE INTO books_plugin_data (book, name, val) VALUES (?, ?, ?)',
+            [(book_id, name, json.dumps(val, default=to_json))
+                    for book_id, val in vals.iteritems()])
+        self.commit()
+
     def get_custom_book_data(self, book_id, name, default=None):
         try:
             s = self.conn.get('''select val FROM books_plugin_data
@@ -3243,11 +3249,29 @@ books_series_link      feeds
             pass
         return default
 
+    def get_all_custom_book_data(self, name, default=None):
+        try:
+            s = self.conn.get('''select book, val FROM books_plugin_data
+                    WHERE name=?''', (name,))
+            if s is None:
+                return default
+            res = {}
+            for r in s:
+                res[r[0]] = json.loads(r[1], object_hook=from_json)
+            return res
+        except:
+            pass
+        return default
+
     def delete_custom_book_data(self, book_id, name):
         self.conn.execute('DELETE FROM books_plugin_data WHERE book=? AND name=?',
                           (book_id, name))
         self.commit()
 
+    def delete_all_custom_book_data(self, name):
+        self.conn.execute('DELETE FROM books_plugin_data WHERE name=?', (name, ))
+        self.commit()
+
     def get_ids_for_custom_book_data(self, name):
         s = self.conn.get('''SELECT book FROM books_plugin_data WHERE name=?''', (name,))
         return [x[0] for x in s]