diff --git a/src/calibre/ebooks/metadata/isbndb.py b/src/calibre/ebooks/metadata/isbndb.py
index 1f0dde3696..3cf5f92eaf 100644
--- a/src/calibre/ebooks/metadata/isbndb.py
+++ b/src/calibre/ebooks/metadata/isbndb.py
@@ -9,7 +9,7 @@ from urllib import urlopen, quote
 
 from calibre import setup_cli_handlers
 from calibre.utils.config import OptionParser
-from calibre.ebooks.metadata import MetaInformation
+from calibre.ebooks.metadata import MetaInformation, authors_to_sort_string
 from calibre.ebooks.BeautifulSoup import BeautifulStoneSoup
 
 BASE_URL = 'http://isbndb.com/api/books.xml?access_key=%(key)s&page_number=1&results=subjects,authors,texts&'
@@ -64,7 +64,8 @@ class ISBNDBMetadata(MetaInformation):
         try:
             self.author_sort = book.find('authors').find('person').string
         except:
-            pass
+            if self.authors:
+                self.author_sort = authors_to_sort_string(self.authors)
         self.publisher = book.find('publishertext').string
         
         summ = book.find('summary')
diff --git a/src/calibre/ebooks/mobi/reader.py b/src/calibre/ebooks/mobi/reader.py
index 1317ab92c2..6cc283be95 100644
--- a/src/calibre/ebooks/mobi/reader.py
+++ b/src/calibre/ebooks/mobi/reader.py
@@ -411,13 +411,12 @@ def get_metadata(stream):
     if mr.book_header.exth is None:
         mi = MetaInformation(mr.name, ['Unknown'])
     else:
-        tdir = tempfile.mkdtemp('mobi-meta', __appname__)
+        tdir = tempfile.mkdtemp('_mobi_meta', __appname__)
         atexit.register(shutil.rmtree, tdir)
         mr.extract_images([], tdir)
         mi = mr.create_opf('dummy.html')
         if mi.cover:
             cover =  os.path.join(tdir, mi.cover)
-            print cover
             if os.access(cover, os.R_OK):
                 mi.cover_data = ('JPEG', open(os.path.join(tdir, mi.cover), 'rb').read())
     return mi
diff --git a/src/calibre/gui2/main.py b/src/calibre/gui2/main.py
index 82cb9e7002..cd82710197 100644
--- a/src/calibre/gui2/main.py
+++ b/src/calibre/gui2/main.py
@@ -1178,6 +1178,7 @@ in which you want to store your books files. Any existing books will be automati
             try:
                 self.olddb = LibraryDatabase(self.database_path)
             except:
+                traceback.print_exc()
                 self.olddb = None
 
 
diff --git a/src/calibre/library/cli.py b/src/calibre/library/cli.py
index 532e8626dc..67f677e68a 100644
--- a/src/calibre/library/cli.py
+++ b/src/calibre/library/cli.py
@@ -51,7 +51,7 @@ XML_TEMPLATE = '''\
         <cover py:if="record['cover']">${record['cover']}</cover>
         <formats py:if="record['formats']">
         <py:for each="path in record['formats']">
-            <format>$path</format>
+            <format>${path}</format>
         </py:for>
         </formats>
     </record>
diff --git a/src/calibre/library/database.py b/src/calibre/library/database.py
index 59f1a65429..1d15c9f838 100644
--- a/src/calibre/library/database.py
+++ b/src/calibre/library/database.py
@@ -30,11 +30,21 @@ class Concatenate(object):
         if self.sep:
             return self.ans[:-len(self.sep)]
         return self.ans
+class Connection(sqlite.Connection):
+    
+    def get(self, *args, **kw):
+        ans = self.execute(*args)
+        if not kw.get('all', True):
+            ans = ans.fetchone()
+            if not ans:
+                ans = [None]
+            return ans[0]
+        return ans.fetchall()
 
 def _connect(path):
     if isinstance(path, unicode):
         path = path.encode('utf-8')
-    conn =  sqlite.connect(path, detect_types=sqlite.PARSE_DECLTYPES|sqlite.PARSE_COLNAMES)
+    conn =  sqlite.connect(path, factory=Connection, detect_types=sqlite.PARSE_DECLTYPES|sqlite.PARSE_COLNAMES)
     conn.row_factory = lambda cursor, row : list(row)
     conn.create_aggregate('concat', 1, Concatenate)
     title_pat = re.compile('^(A|The|An)\s+', re.IGNORECASE)
@@ -812,11 +822,11 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
     def user_version():
         doc = 'The user version of this database'
         def fget(self):
-            return self.conn.execute('pragma user_version;').next()[0]
+            return self.conn.get('pragma user_version;', all=False)
         return property(doc=doc, fget=fget)
 
     def is_empty(self):
-        return not self.conn.execute('SELECT id FROM books LIMIT 1').fetchone()
+        return not self.conn.get('SELECT id FROM books LIMIT 1', all=False)
 
     def refresh(self, sort_field, ascending):
         '''
@@ -846,14 +856,14 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
         else:
             sort += ',title '+order
 
-        self.cache = self.conn.execute('SELECT * from meta ORDER BY '+sort).fetchall()
+        self.cache = self.conn.get('SELECT * from meta ORDER BY '+sort)
         self.data  = self.cache
         self.conn.commit()
 
     def refresh_ids(self, ids):
         indices = map(self.index, ids)
         for id, idx in zip(ids, indices):
-            row = self.conn.execute('SELECT * from meta WHERE id=?', (id,)).fetchone()
+            row = self.conn.get('SELECT * from meta WHERE id=?', (id,), all=False)
             self.data[idx] = row
         return indices
 
@@ -905,7 +915,7 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
         if not index_is_id:
             return self.data[index][1]
         try:
-            return self.conn.execute('SELECT title FROM meta WHERE id=?',(index,)).fetchone()[0]
+            return self.conn.get('SELECT title FROM meta WHERE id=?',(index,), all=False)
         except:
             return _('Unknown')
 
@@ -917,73 +927,69 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
         if not index_is_id:
             return self.data[index][2]
         try:
-            return self.conn.execute('SELECT authors FROM meta WHERE id=?',(index,)).fetchone()[0]
+            return self.conn.get('SELECT authors FROM meta WHERE id=?',(index,), all=False)
         except:
             pass
 
     def isbn(self, idx, index_is_id=False):
         id = idx if index_is_id else self.id(idx)
-        return self.conn.execute('SELECT isbn FROM books WHERE id=?',(id,)).fetchone()[0]
+        return self.conn.get('SELECT isbn FROM books WHERE id=?',(id,), all=False)
 
     def author_sort(self, index, index_is_id=False):
         id = index if index_is_id else self.id(index)
-        return self.conn.execute('SELECT author_sort FROM books WHERE id=?', (id,)).fetchone()[0]
+        return self.conn.get('SELECT author_sort FROM books WHERE id=?', (id,), all=False)
 
     def publisher(self, index, index_is_id=False):
         if index_is_id:
-            return self.conn.execute('SELECT publisher FROM meta WHERE id=?', (index,)).fetchone()[0]
+            return self.conn.get('SELECT publisher FROM meta WHERE id=?', (index,), all=False)
         return self.data[index][3]
 
     def rating(self, index, index_is_id=False):
         if index_is_id:
-            return self.conn.execute('SELECT rating FROM meta WHERE id=?', (index,)).fetchone()[0]
+            return self.conn.get('SELECT rating FROM meta WHERE id=?', (index,), all=False)
         return self.data[index][4]
 
     def timestamp(self, index, index_is_id=False):
         if index_is_id:
-            return self.conn.execute('SELECT timestamp FROM meta WHERE id=?', (index,)).fetchone()[0]
+            return self.conn.get('SELECT timestamp FROM meta WHERE id=?', (index,), all=False)
         return self.data[index][5]
 
     def max_size(self, index, index_is_id=False):
         if index_is_id:
-            return self.conn.execute('SELECT size FROM meta WHERE id=?', (index,)).fetchone()[0]
+            return self.conn.get('SELECT size FROM meta WHERE id=?', (index,), all=False)
         return self.data[index][6]
 
     def cover(self, index, index_is_id=False):
         '''Cover as a data string or None'''
         id = index if index_is_id else self.id(index)
-        data = self.conn.execute('SELECT data FROM covers WHERE book=?', (id,)).fetchone()
-        if not data or not data[0]:
+        data = self.conn.get('SELECT data FROM covers WHERE book=?', (id,), all=False)
+        if not data:
             return None
-        return(decompress(data[0]))
+        return(decompress(data))
 
     def tags(self, index, index_is_id=False):
         '''tags as a comma separated list or None'''
         id = index if index_is_id else self.id(index)
-        matches = self.conn.execute('SELECT concat(name) FROM tags WHERE tags.id IN (SELECT tag from books_tags_link WHERE book=?)', (id,)).fetchall()
+        matches = self.conn.get('SELECT concat(name) FROM tags WHERE tags.id IN (SELECT tag from books_tags_link WHERE book=?)', (id,))
         if not matches or not matches[0][0]:
             return None
         matches = [t.lower().strip() for t in matches[0][0].split(',')]
         return ','.join(matches)
 
     def series_id(self, index, index_is_id=False):
-        id = index if index_is_id else self.id(index)
-        ans= self.conn.execute('SELECT series from books_series_link WHERE book=?', (id,)).fetchone()
-        if ans:
-            return ans[0]
+        id  = index if index_is_id else self.id(index)
+        return self.conn.get('SELECT series from books_series_link WHERE book=?', (id,), all=False)
 
     def series(self, index, index_is_id=False):
         id = self.series_id(index, index_is_id)
-        ans = self.conn.execute('SELECT name from series WHERE id=?', (id,)).fetchone()
-        if ans:
-            return ans[0]
-
+        return self.conn.get('SELECT name from series WHERE id=?', (id,), all=False)
+        
     def series_index(self, index, index_is_id=False):
         ans = None
         if not index_is_id:
             ans = self.data[index][10]
         else:
-            ans = self.conn.execute('SELECT series_index FROM books WHERE id=?', (index,)).fetchone()[0]
+            ans = self.conn.get('SELECT series_index FROM books WHERE id=?', (index,), all=False)
         try:
             return int(ans)
         except:
@@ -994,8 +1000,8 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
         Return an ordered list of all books in the series.
         The list contains book ids.
         '''
-        ans = self.conn.execute('SELECT book from books_series_link WHERE series=?',
-                                (series_id,)).fetchall()
+        ans = self.conn.get('SELECT book from books_series_link WHERE series=?',
+                                (series_id,))
         if not ans:
             return []
         ans = [id[0] for id in ans]
@@ -1014,41 +1020,35 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
     def comments(self, index, index_is_id=False):
         '''Comments as string or None'''
         id = index if index_is_id else self.id(index)
-        matches = self.conn.execute('SELECT text FROM comments WHERE book=?', (id,)).fetchall()
-        if not matches:
-            return None
-        return matches[0][0]
-
+        return self.conn.get('SELECT text FROM comments WHERE book=?', (id,), all=False)
+        
     def formats(self, index, index_is_id=False):
         ''' Return available formats as a comma separated list '''
         id = index if index_is_id else self.id(index)
-        matches = self.conn.execute('SELECT concat(format) FROM data WHERE data.book=?', (id,)).fetchall()
-        if not matches:
-            return None
-        return matches[0][0]
+        return self.conn.get('SELECT concat(format) FROM data WHERE data.book=?', (id,), all=False)
 
     def sizeof_format(self, index, format, index_is_id=False):
         ''' Return size of C{format} for book C{index} in bytes'''
         id = index if index_is_id else self.id(index)
         format = format.upper()
-        return self.conn.execute('SELECT uncompressed_size FROM data WHERE data.book=? AND data.format=?', (id, format)).fetchone()[0]
+        return self.conn.get('SELECT uncompressed_size FROM data WHERE data.book=? AND data.format=?', (id, format), all=False)
 
 
     def format(self, index, format, index_is_id=False):
         id = index if index_is_id else self.id(index)
-        return decompress(self.conn.execute('SELECT data FROM data WHERE book=? AND format=?', (id, format)).fetchone()[0])
+        return decompress(self.conn.get('SELECT data FROM data WHERE book=? AND format=?', (id, format), all=False))
 
     def all_series(self):
         return [ (i[0], i[1]) for i in \
-                self.conn.execute('SELECT id, name FROM series').fetchall()]
+                self.conn.get('SELECT id, name FROM series')]
 
     def all_tags(self):
-        return [i[0].strip() for i in self.conn.execute('SELECT name FROM tags').fetchall() if i[0].strip()]
+        return [i[0].strip() for i in self.conn.get('SELECT name FROM tags') if i[0].strip()]
 
     def conversion_options(self, id, format):
-        data = self.conn.execute('SELECT data FROM conversion_options WHERE book=? AND format=?', (id, format.upper())).fetchone()
+        data = self.conn.get('SELECT data FROM conversion_options WHERE book=? AND format=?', (id, format.upper()), all=False)
         if data:
-            return cPickle.loads(str(data[0]))
+            return cPickle.loads(str(data))
         return None
 
 
@@ -1108,9 +1108,9 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
 
     def set_conversion_options(self, id, format, options):
         data = sqlite.Binary(cPickle.dumps(options, -1))
-        oid = self.conn.execute('SELECT id FROM conversion_options WHERE book=? AND format=?', (id, format.upper())).fetchone()
+        oid = self.conn.get('SELECT id FROM conversion_options WHERE book=? AND format=?', (id, format.upper()), all=False)
         if oid:
-            self.conn.execute('UPDATE conversion_options SET data=? WHERE id=?', (data, oid[0]))
+            self.conn.execute('UPDATE conversion_options SET data=? WHERE id=?', (data, oid))
         else:
             self.conn.execute('INSERT INTO conversion_options(book,format,data) VALUES (?,?,?)', (id,format.upper(),data))
         self.conn.commit()
@@ -1125,9 +1125,9 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
             if not a:
                 continue
             a = a.strip()
-            author = self.conn.execute('SELECT id from authors WHERE name=?', (a,)).fetchone()
+            author = self.conn.get('SELECT id from authors WHERE name=?', (a,), all=False)
             if author:
-                aid = author[0]
+                aid = author
                 # Handle change of case
                 self.conn.execute('UPDATE authors SET name=? WHERE id=?', (a, aid))
             else:
@@ -1155,9 +1155,9 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
     def set_publisher(self, id, publisher):
         self.conn.execute('DELETE FROM books_publishers_link WHERE book=?',(id,))
         if publisher:
-            pub = self.conn.execute('SELECT id from publishers WHERE name=?', (publisher,)).fetchone()
+            pub = self.conn.get('SELECT id from publishers WHERE name=?', (publisher,), all=False)
             if pub:
-                aid = pub[0]
+                aid = pub
             else:
                 aid = self.conn.execute('INSERT INTO publishers(name) VALUES (?)', (publisher,)).lastrowid
             self.conn.execute('INSERT INTO books_publishers_link(book, publisher) VALUES (?,?)', (id, aid))
@@ -1169,15 +1169,14 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
         self.conn.commit()
 
     def is_tag_used(self, tag):
-        id = self.conn.execute('SELECT id FROM tags WHERE name=?', (tag,)).fetchone()
+        id = self.conn.get('SELECT id FROM tags WHERE name=?', (tag,), all=False)
         if not id:
             return False
-        return bool(self.conn.execute('SELECT tag FROM books_tags_link WHERE tag=?',(id[0],)).fetchone())
+        return bool(self.conn.get('SELECT tag FROM books_tags_link WHERE tag=?',(id,), all=False))
 
     def delete_tag(self, tag):
-        id = self.conn.execute('SELECT id FROM tags WHERE name=?', (tag,)).fetchone()
+        id = self.conn.get('SELECT id FROM tags WHERE name=?', (tag,), all=False)
         if id:
-            id = id[0]
             self.conn.execute('DELETE FROM books_tags_link WHERE tag=?', (id,))
             self.conn.execute('DELETE FROM tags WHERE id=?', (id,))
             self.conn.commit()
@@ -1188,9 +1187,9 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
 
     def unapply_tags(self, book_id, tags):
         for tag in tags:
-            id = self.conn.execute('SELECT id FROM tags WHERE name=?', (tag,)).fetchone()
+            id = self.conn.get('SELECT id FROM tags WHERE name=?', (tag,), all=False)
             if id:
-                self.conn.execute('DELETE FROM books_tags_link WHERE tag=? AND book=?', (id[0], book_id))
+                self.conn.execute('DELETE FROM books_tags_link WHERE tag=? AND book=?', (id, book_id))
         self.conn.commit()
 
     def set_tags(self, id, tags, append=False):
@@ -1204,14 +1203,14 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
             tag = tag.lower().strip()
             if not tag:
                 continue
-            t = self.conn.execute('SELECT id FROM tags WHERE name=?', (tag,)).fetchone()
+            t = self.conn.get('SELECT id FROM tags WHERE name=?', (tag,), all=False)
             if t:
-                tid = t[0]
+                tid = t
             else:
                 tid = self.conn.execute('INSERT INTO tags(name) VALUES(?)', (tag,)).lastrowid
 
-            if not self.conn.execute('SELECT book FROM books_tags_link WHERE book=? AND tag=?',
-                                        (id, tid)).fetchone():
+            if not self.conn.get('SELECT book FROM books_tags_link WHERE book=? AND tag=?',
+                                        (id, tid), all=False):
                 self.conn.execute('INSERT INTO books_tags_link(book, tag) VALUES (?,?)',
                               (id, tid))
         self.conn.commit()
@@ -1220,9 +1219,9 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
     def set_series(self, id, series):
         self.conn.execute('DELETE FROM books_series_link WHERE book=?',(id,))
         if series:
-            s = self.conn.execute('SELECT id from series WHERE name=?', (series,)).fetchone()
+            s = self.conn.get('SELECT id from series WHERE name=?', (series,), all=False)
             if s:
-                aid = s[0]
+                aid = s
             else:
                 aid = self.conn.execute('INSERT INTO series(name) VALUES (?)', (series,)).lastrowid
             self.conn.execute('INSERT INTO books_series_link(book, series) VALUES (?,?)', (id, aid))
@@ -1232,8 +1231,8 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
             self.data[row][9] = series
 
     def remove_unused_series(self):
-        for id, in self.conn.execute('SELECT id FROM series').fetchall():
-            if not self.conn.execute('SELECT id from books_series_link WHERE series=?', (id,)).fetchone():
+        for id, in self.conn.get('SELECT id FROM series'):
+            if not self.conn.get('SELECT id from books_series_link WHERE series=?', (id,)):
                 self.conn.execute('DELETE FROM series WHERE id=?', (id,))
         self.conn.commit()
 
@@ -1248,8 +1247,8 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
     def set_rating(self, id, rating):
         rating = int(rating)
         self.conn.execute('DELETE FROM books_ratings_link WHERE book=?',(id,))
-        rat = self.conn.execute('SELECT id FROM ratings WHERE rating=?', (rating,)).fetchone()
-        rat = rat[0] if rat else self.conn.execute('INSERT INTO ratings(rating) VALUES (?)', (rating,)).lastrowid
+        rat = self.conn.get('SELECT id FROM ratings WHERE rating=?', (rating,), all=False)
+        rat = rat if rat else self.conn.execute('INSERT INTO ratings(rating) VALUES (?)', (rating,)).lastrowid
         self.conn.execute('INSERT INTO books_ratings_link(book, rating) VALUES (?,?)', (id, rat))
         self.conn.commit()
 
@@ -1336,7 +1335,7 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
                 return i
 
     def get_feeds(self):
-        feeds = self.conn.execute('SELECT title, script FROM feeds').fetchall()
+        feeds = self.conn.get('SELECT title, script FROM feeds')
         for title, script in feeds:
             yield title, script
 
@@ -1386,7 +1385,7 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
         self.conn.commit()
 
     def all_ids(self):
-        return [i[0] for i in self.conn.execute('SELECT id FROM books').fetchall()]
+        return [i[0] for i in self.conn.get('SELECT id FROM books')]
 
     def export_to_dir(self, dir, indices, byauthor=False, single_dir=False,
                       index_is_id=False):
@@ -1395,8 +1394,8 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
         by_author = {}
         for index in indices:
             id = index if index_is_id else self.id(index)
-            au = self.conn.execute('SELECT author_sort FROM books WHERE id=?',
-                                   (id,)).fetchone()[0]
+            au = self.conn.get('SELECT author_sort FROM books WHERE id=?',
+                                   (id,), all=False)
             if not au:
                 au = self.authors(index, index_is_id=index_is_id)
                 if not au:
@@ -1540,10 +1539,10 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
 
 
     def has_book(self, mi):
-        return bool(self.conn.execute('SELECT id FROM books where title=?', (mi.title,)).fetchone())
+        return bool(self.conn.get('SELECT id FROM books where title=?', (mi.title,), all=False))
 
     def has_id(self, id):
-        return self.conn.execute('SELECT id FROM books where id=?', (id,)).fetchone() is not None
+        return self.conn.get('SELECT id FROM books where id=?', (id,), all=False) is not None
 
     def recursive_import(self, root, single_book_per_directory=True):
         root = os.path.abspath(root)
diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index 0267691275..ad203ecf4a 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -8,7 +8,6 @@ The database used to store ebook metadata
 '''
 import os, re, sys, shutil, cStringIO, glob, collections, textwrap, \
        operator, itertools, functools, traceback
-import sqlite3 as sqlite
 from itertools import repeat
 
 from PyQt4.QtCore import QCoreApplication, QThread, QReadWriteLock
@@ -16,9 +15,11 @@ from PyQt4.QtGui import QApplication, QPixmap, QImage
 __app = None
 
 from calibre.library.database import LibraryDatabase
+from calibre.library.sqlite import connect, IntegrityError
 from calibre.ebooks.metadata import string_to_authors, authors_to_string
 from calibre.constants import preferred_encoding, iswindows, isosx
 
+
 copyfile = os.link if hasattr(os, 'link') else shutil.copyfile
 filesystem_encoding = sys.getfilesystemencoding()
 if filesystem_encoding is None: filesystem_encoding = 'utf-8'
@@ -157,23 +158,6 @@ class CoverCache(QThread):
             self.load_queue.appendleft(id)
         self.load_queue_lock.unlock()
     
-class Concatenate(object):
-    '''String concatenation aggregator for sqlite'''
-    def __init__(self, sep=','):
-        self.sep = sep
-        self.ans = ''
-        
-    def step(self, value):
-        if value is not None:
-            self.ans += value + self.sep
-    
-    def finalize(self):
-        if not self.ans:
-            return None
-        if self.sep:
-            return self.ans[:-len(self.sep)]
-        return self.ans
-    
 class ResultCache(object):
     
     '''
@@ -226,7 +210,7 @@ class ResultCache(object):
     
     def refresh_ids(self, conn, ids):
         for id in ids:
-            self._data[id] = conn.execute('SELECT * from meta WHERE id=?', (id,)).fetchone()
+            self._data[id] = conn.get('SELECT * from meta WHERE id=?', (id,))[0]
         return map(self.row, ids)
     
     def books_added(self, ids, conn):
@@ -234,7 +218,7 @@ class ResultCache(object):
             return
         self._data.extend(repeat(None, max(ids)-len(self._data)+2))
         for id in ids:
-            self._data[id] = conn.execute('SELECT * from meta WHERE id=?', (id,)).fetchone()
+            self._data[id] = conn.get('SELECT * from meta WHERE id=?', (id,))[0]
         self._map[0:0] = ids
         self._map_filtered[0:0] = ids
     
@@ -246,7 +230,7 @@ class ResultCache(object):
         # Fast mapping from sorted, filtered row numbers to ids
         # At the moment it is the same as self._map
         self._map_filtered = list(self._map)
-        temp = db.conn.execute('SELECT * FROM meta').fetchall()
+        temp = db.conn.get('SELECT * FROM meta')
         # Fast mapping from ids to data. 
         # Can be None for ids that dont exist (i.e. have been deleted)
         self._data = list(itertools.repeat(None, temp[-1][0]+2)) if temp else []
@@ -285,53 +269,53 @@ class ResultCache(object):
                 self._map_filtered.remove(id)
     
     def sort_on_title(self, order, db):
-        return db.conn.execute('SELECT id FROM books ORDER BY sort ' + order).fetchall()
+        return db.conn.get('SELECT id FROM books ORDER BY sort ' + order)
     
     def sort_on_author_sort(self, order, db):
-        return db.conn.execute('SELECT id FROM books ORDER BY author_sort,sort ' + order).fetchall()
+        return db.conn.get('SELECT id FROM books ORDER BY author_sort,sort ' + order)
     
     def sort_on_timestamp(self, order, db):
-        return db.conn.execute('SELECT id FROM books ORDER BY id ' + order).fetchall()
+        return db.conn.get('SELECT id FROM books ORDER BY id ' + order)
     
     def sort_on_publisher(self, order, db):
-        no_publisher = db.conn.execute('SELECT id FROM books WHERE books.id NOT IN (SELECT book FROM books_publishers_link) ORDER BY books.sort').fetchall()
+        no_publisher = db.conn.get('SELECT id FROM books WHERE books.id NOT IN (SELECT book FROM books_publishers_link) ORDER BY books.sort')
         ans = []
-        for r in db.conn.execute('SELECT id FROM publishers ORDER BY name '+order).fetchall():
+        for r in db.conn.get('SELECT id FROM publishers ORDER BY name '+order):
             publishers_id = r[0]
-            ans += db.conn.execute('SELECT id FROM books WHERE books.id IN (SELECT book FROM books_publishers_link WHERE publisher=?) ORDER BY books.sort '+order, (publishers_id,)).fetchall()
+            ans += db.conn.get('SELECT id FROM books WHERE books.id IN (SELECT book FROM books_publishers_link WHERE publisher=?) ORDER BY books.sort '+order, (publishers_id,))
         ans = (no_publisher + ans) if order == 'ASC' else (ans + no_publisher)
         return ans 
         
 
     def sort_on_size(self, order, db): 
-        return db.conn.execute('SELECT id FROM meta ORDER BY size ' + order).fetchall()
+        return db.conn.get('SELECT id FROM meta ORDER BY size ' + order)
     
     def sort_on_rating(self, order, db): 
-        no_rating = db.conn.execute('SELECT id FROM books WHERE books.id NOT IN (SELECT book FROM books_ratings_link) ORDER BY books.sort').fetchall()
+        no_rating = db.conn.get('SELECT id FROM books WHERE books.id NOT IN (SELECT book FROM books_ratings_link) ORDER BY books.sort')
         ans = []
-        for r in db.conn.execute('SELECT id FROM ratings ORDER BY rating '+order).fetchall():
+        for r in db.conn.get('SELECT id FROM ratings ORDER BY rating '+order):
             ratings_id = r[0]
-            ans += db.conn.execute('SELECT id FROM books WHERE books.id IN (SELECT book FROM books_ratings_link WHERE rating=?) ORDER BY books.sort', (ratings_id,)).fetchall()
+            ans += db.conn.get('SELECT id FROM books WHERE books.id IN (SELECT book FROM books_ratings_link WHERE rating=?) ORDER BY books.sort', (ratings_id,))
         ans = (no_rating + ans) if order == 'ASC' else (ans + no_rating)
         return ans 
         
     
     def sort_on_series(self, order, db):
-        no_series = db.conn.execute('SELECT id FROM books WHERE books.id NOT IN (SELECT book FROM books_series_link) ORDER BY books.sort').fetchall()
+        no_series = db.conn.get('SELECT id FROM books WHERE books.id NOT IN (SELECT book FROM books_series_link) ORDER BY books.sort')
         ans = []
-        for r in db.conn.execute('SELECT id FROM series ORDER BY name '+order).fetchall():
+        for r in db.conn.get('SELECT id FROM series ORDER BY name '+order):
             series_id = r[0]
-            ans += db.conn.execute('SELECT id FROM books WHERE books.id IN (SELECT book FROM books_series_link WHERE series=?) ORDER BY books.series_index,books.id '+order, (series_id,)).fetchall()
+            ans += db.conn.get('SELECT id FROM books WHERE books.id IN (SELECT book FROM books_series_link WHERE series=?) ORDER BY books.series_index,books.id '+order, (series_id,))
         ans = (no_series + ans) if order == 'ASC' else (ans + no_series)
         return ans 
         
     
     def sort_on_tags(self, order, db):
-        no_tags = db.conn.execute('SELECT id FROM books WHERE books.id NOT IN (SELECT book FROM books_tags_link) ORDER BY books.sort').fetchall()
+        no_tags = db.conn.get('SELECT id FROM books WHERE books.id NOT IN (SELECT book FROM books_tags_link) ORDER BY books.sort')
         ans = []
-        for r in db.conn.execute('SELECT id FROM tags ORDER BY name '+order).fetchall():
+        for r in db.conn.get('SELECT id FROM tags ORDER BY name '+order):
             tag_id = r[0]
-            ans += db.conn.execute('SELECT id FROM books WHERE books.id IN (SELECT book FROM books_tags_link WHERE tag=?) ORDER BY books.sort '+order, (tag_id,)).fetchall()
+            ans += db.conn.get('SELECT id FROM books WHERE books.id IN (SELECT book FROM books_tags_link WHERE tag=?) ORDER BY books.sort '+order, (tag_id,))
         ans = (no_tags + ans) if order == 'ASC' else (ans + no_tags)
         return ans 
 
@@ -353,36 +337,25 @@ class LibraryDatabase2(LibraryDatabase):
     @apply
     def user_version():
         doc = 'The user version of this database'
+        
         def fget(self):
-            return self.conn.execute('pragma user_version;').next()[0]
+            return self.conn.get('pragma user_version;', all=False)
+        
         def fset(self, val):
             self.conn.execute('pragma user_version=%d'%int(val))
             self.conn.commit()
+        
         return property(doc=doc, fget=fget, fset=fset)
     
     def connect(self):
         if 'win32' in sys.platform and len(self.library_path) + 4*self.PATH_LIMIT + 10 > 259:
             raise ValueError('Path to library too long. Must be less than %d characters.'%(259-4*self.PATH_LIMIT-10))
         exists = os.path.exists(self.dbpath)
-        self.conn = sqlite.connect(self.dbpath, 
-                                detect_types=sqlite.PARSE_DECLTYPES|sqlite.PARSE_COLNAMES)
+        self.conn = connect(self.dbpath, self.row_factory)
         if exists and self.user_version == 0:
             self.conn.close()
             os.remove(self.dbpath)
-            self.conn = sqlite.connect(self.dbpath, 
-                                detect_types=sqlite.PARSE_DECLTYPES|sqlite.PARSE_COLNAMES)
-        self.conn.row_factory = sqlite.Row if self.row_factory else  lambda cursor, row : list(row)
-        self.conn.create_aggregate('concat', 1, Concatenate)
-        title_pat = re.compile('^(A|The|An)\s+', re.IGNORECASE)
-        
-        def title_sort(title):
-            match = title_pat.search(title)
-            if match:
-                prep = match.group(1)
-                title = title.replace(prep, '') + ', ' + prep
-            return title.strip()
-        
-        self.conn.create_function('title_sort', 1, title_sort)
+            self.conn = connect(self.dbpath, self.row_factory)
         if self.user_version == 0: 
             self.initialize_database()
     
@@ -453,7 +426,7 @@ class LibraryDatabase2(LibraryDatabase):
     def path(self, index, index_is_id=False):
         'Return the relative path to the directory containing this books files as a unicode string.'
         id = index if index_is_id else self.id(index)
-        path = self.conn.execute('SELECT path FROM books WHERE id=?', (id,)).fetchone()[0].replace('/', os.sep)
+        path = self.conn.get('SELECT path FROM books WHERE id=?', (id,), all=False).replace('/', os.sep)
         return path
     
     def abspath(self, index, index_is_id=False):
@@ -503,7 +476,7 @@ class LibraryDatabase2(LibraryDatabase):
         fname = self.construct_file_name(id)
         changed = False
         for format in formats:
-            name = self.conn.execute('SELECT name FROM data WHERE book=? AND format=?', (id, format)).fetchone()[0]
+            name = self.conn.get('SELECT name FROM data WHERE book=? AND format=?', (id, format), all=False)
             if name and name != fname:
                 changed = True
                 break
@@ -594,7 +567,7 @@ class LibraryDatabase2(LibraryDatabase):
             p.save(path)
             
     def all_formats(self):
-        formats = self.conn.execute('SELECT format from data').fetchall()
+        formats = self.conn.get('SELECT format from data')
         if not formats:
             return set([])
         return set([f[0] for f in formats])
@@ -604,8 +577,8 @@ class LibraryDatabase2(LibraryDatabase):
         id = index if index_is_id else self.id(index)
         path = os.path.join(self.library_path, self.path(id, index_is_id=True))
         try:
-            formats = self.conn.execute('SELECT format FROM data WHERE book=?', (id,)).fetchall()
-            name = self.conn.execute('SELECT name FROM data WHERE book=?', (id,)).fetchone()[0]
+            formats = self.conn.get('SELECT format FROM data WHERE book=?', (id,))
+            name = self.conn.get('SELECT name FROM data WHERE book=?', (id,), all=False)
             formats = map(lambda x:x[0], formats)
         except:
             return None
@@ -621,7 +594,7 @@ class LibraryDatabase2(LibraryDatabase):
         'Return absolute path to the ebook file of format `format`'
         id = index if index_is_id else self.id(index)
         path = os.path.join(self.library_path, self.path(id, index_is_id=True))
-        name = self.conn.execute('SELECT name FROM data WHERE book=? AND format=?', (id, format)).fetchone()[0]
+        name = self.conn.get('SELECT name FROM data WHERE book=? AND format=?', (id, format), all=False)
         if name:
             format = ('.' + format.lower()) if format else ''
             path = os.path.join(path, name+format)
@@ -645,7 +618,7 @@ class LibraryDatabase2(LibraryDatabase):
         id = index if index_is_id else self.id(index)
         if path is None:
             path = os.path.join(self.library_path, self.path(id, index_is_id=True))
-        name = self.conn.execute('SELECT name FROM data WHERE book=? AND format=?', (id, format)).fetchone()
+        name = self.conn.get('SELECT name FROM data WHERE book=? AND format=?', (id, format), all=False)
         if name:
             self.conn.execute('DELETE FROM data WHERE book=? AND format=?', (id, format))
         name = self.construct_file_name(id)
@@ -682,7 +655,7 @@ class LibraryDatabase2(LibraryDatabase):
     def remove_format(self, index, format, index_is_id=False):
         id = index if index_is_id else self.id(index)
         path = os.path.join(self.library_path, self.path(id, index_is_id=True))
-        name = self.conn.execute('SELECT name FROM data WHERE book=? AND format=?', (id, format)).fetchone()
+        name = self.conn.get('SELECT name FROM data WHERE book=? AND format=?', (id, format), all=False)
         name = name[0] if name else False
         if name:
             ext = ('.' + format.lower()) if format else ''
@@ -709,7 +682,7 @@ class LibraryDatabase2(LibraryDatabase):
     def get_categories(self, sort_on_count=False):
         categories = {}
         def get(name, category, field='name'):
-            ans = self.conn.execute('SELECT DISTINCT %s FROM %s'%(field, name)).fetchall()
+            ans = self.conn.get('SELECT DISTINCT %s FROM %s'%(field, name))
             ans = [x[0].strip() for x in ans]
             try:
                 ans.remove('')
@@ -718,16 +691,14 @@ class LibraryDatabase2(LibraryDatabase):
             tags = categories[category]
             if name != 'data':
                 for tag in tags:
-                    id = self.conn.execute('SELECT id FROM %s WHERE %s=?'%(name, field), (tag,)).fetchone()
-                    if id:
-                        id = id[0]
+                    id = self.conn.get('SELECT id FROM %s WHERE %s=?'%(name, field), (tag,), all=False)
                     tag.id = id
                 for tag in tags:
                     if tag.id is not None:
-                        tag.count = self.conn.execute('SELECT COUNT(id) FROM books_%s_link WHERE %s=?'%(name, category), (tag.id,)).fetchone()[0]
+                        tag.count = self.conn.get('SELECT COUNT(id) FROM books_%s_link WHERE %s=?'%(name, category), (tag.id,), all=False)
             else:
                 for tag in tags:
-                    tag.count = self.conn.execute('SELECT COUNT(format) FROM data WHERE format=?', (tag,)).fetchone()[0]
+                    tag.count = self.conn.get('SELECT COUNT(format) FROM data WHERE format=?', (tag,), all=False)
             tags.sort(reverse=sort_on_count, cmp=(lambda x,y:cmp(x.count,y.count)) if sort_on_count else cmp)
         for x in (('authors', 'author'), ('tags', 'tag'), ('publishers', 'publisher'), 
                   ('series', 'series')):
@@ -785,6 +756,8 @@ class LibraryDatabase2(LibraryDatabase):
             self.set_tags(id, mi.tags, notify=False)
         if mi.comments:
             self.set_comment(id, mi.comments)
+        if mi.isbn and mi.isbn.strip():
+            self.set_isbn(id, mi.isbn)
         self.set_path(id, True)
         self.notify('metadata', [id])
         
@@ -800,16 +773,16 @@ class LibraryDatabase2(LibraryDatabase):
             a = a.strip().replace(',', '|')
             if not isinstance(a, unicode):
                 a = a.decode(preferred_encoding, 'replace')
-            author = self.conn.execute('SELECT id from authors WHERE name=?', (a,)).fetchone()
+            author = self.conn.get('SELECT id from authors WHERE name=?', (a,), all=False)
             if author:
-                aid = author[0]
+                aid = author
                 # Handle change of case
                 self.conn.execute('UPDATE authors SET name=? WHERE id=?', (a, aid))
             else:
                 aid = self.conn.execute('INSERT INTO authors(name) VALUES (?)', (a,)).lastrowid
             try:
                 self.conn.execute('INSERT INTO books_authors_link(book, author) VALUES (?,?)', (id, aid))
-            except sqlite.IntegrityError: # Sometimes books specify the same author twice in their metadata
+            except IntegrityError: # Sometimes books specify the same author twice in their metadata
                 pass
         self.set_path(id, True)
         self.notify('metadata', [id])
@@ -829,9 +802,9 @@ class LibraryDatabase2(LibraryDatabase):
         if publisher:
             if not isinstance(publisher, unicode):
                 publisher = publisher.decode(preferred_encoding, 'replace')
-            pub = self.conn.execute('SELECT id from publishers WHERE name=?', (publisher,)).fetchone()
+            pub = self.conn.get('SELECT id from publishers WHERE name=?', (publisher,), all=False)
             if pub:
-                aid = pub[0]
+                aid = pub
             else:
                 aid = self.conn.execute('INSERT INTO publishers(name) VALUES (?)', (publisher,)).lastrowid
             self.conn.execute('INSERT INTO books_publishers_link(book, publisher) VALUES (?,?)', (id, aid))
@@ -852,14 +825,14 @@ class LibraryDatabase2(LibraryDatabase):
                 continue
             if not isinstance(tag, unicode):
                 tag = tag.decode(preferred_encoding, 'replace')
-            t = self.conn.execute('SELECT id FROM tags WHERE name=?', (tag,)).fetchone()
+            t = self.conn.get('SELECT id FROM tags WHERE name=?', (tag,), all=False)
             if t:
-                tid = t[0]
+                tid = t
             else:
                 tid = self.conn.execute('INSERT INTO tags(name) VALUES(?)', (tag,)).lastrowid
 
-            if not self.conn.execute('SELECT book FROM books_tags_link WHERE book=? AND tag=?',
-                                        (id, tid)).fetchone():
+            if not self.conn.get('SELECT book FROM books_tags_link WHERE book=? AND tag=?',
+                                        (id, tid), all=False):
                 self.conn.execute('INSERT INTO books_tags_link(book, tag) VALUES (?,?)',
                               (id, tid))
         self.conn.commit()
@@ -872,9 +845,9 @@ class LibraryDatabase2(LibraryDatabase):
         if series:
             if not isinstance(series, unicode):
                 series = series.decode(preferred_encoding, 'replace')
-            s = self.conn.execute('SELECT id from series WHERE name=?', (series,)).fetchone()
+            s = self.conn.get('SELECT id from series WHERE name=?', (series,), all=False)
             if s:
-                aid = s[0]
+                aid = s
             else:
                 aid = self.conn.execute('INSERT INTO series(name) VALUES (?)', (series,)).lastrowid
             self.conn.execute('INSERT INTO books_series_link(book, series) VALUES (?,?)', (id, aid))
@@ -904,7 +877,7 @@ class LibraryDatabase2(LibraryDatabase):
     def add_books(self, paths, formats, metadata, uris=[], add_duplicates=True):
         '''
         Add a book to the database. The result cache is not updated.
-        @param paths: List of paths to book files of file-like objects
+        @param paths: List of paths to book files or file-like objects
         '''
         formats, metadata, uris = iter(formats), iter(metadata), iter(uris)
         duplicates = []
@@ -965,7 +938,7 @@ class LibraryDatabase2(LibraryDatabase):
         
     def move_library_to(self, newloc, progress=None):
         header = _(u'<p>Copying books to %s<br><center>')%newloc
-        books = self.conn.execute('SELECT id, path, title FROM books').fetchall()
+        books = self.conn.get('SELECT id, path, title FROM books')
         if progress is not None:
             progress.setValue(0)
             progress.setLabelText(header)
@@ -1047,6 +1020,7 @@ class LibraryDatabase2(LibraryDatabase):
                     x['formats'].append(path%fmt.lower())
                     x['fmt_'+fmt.lower()] = path%fmt.lower()
                 x['available_formats'] = [i.upper() for i in formats.split(',')]
+            
         return data
     
     def migrate_old(self, db, progress):
@@ -1056,7 +1030,7 @@ class LibraryDatabase2(LibraryDatabase):
         QCoreApplication.processEvents()
         db.conn.row_factory = lambda cursor, row : tuple(row)
         db.conn.text_factory = lambda x : unicode(x, 'utf-8', 'replace')
-        books = db.conn.execute('SELECT id, title, sort, timestamp, uri, series_index, author_sort, isbn FROM books ORDER BY id ASC').fetchall()
+        books = db.conn.get('SELECT id, title, sort, timestamp, uri, series_index, author_sort, isbn FROM books ORDER BY id ASC')
         progress.setAutoReset(False)
         progress.setRange(0, len(books))
         
@@ -1072,7 +1046,7 @@ books_ratings_link
 books_series_link      feeds
 '''.split()
         for table in tables:
-            rows = db.conn.execute('SELECT * FROM %s ORDER BY id ASC'%table).fetchall() 
+            rows = db.conn.get('SELECT * FROM %s ORDER BY id ASC'%table) 
             for row in rows:
                 self.conn.execute('INSERT INTO %s VALUES(%s)'%(table, ','.join(repeat('?', len(row)))), row)
                 
diff --git a/src/calibre/library/server.py b/src/calibre/library/server.py
new file mode 100644
index 0000000000..d1d48145f7
--- /dev/null
+++ b/src/calibre/library/server.py
@@ -0,0 +1,43 @@
+#!/usr/bin/env  python
+__license__   = 'GPL v3'
+__copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
+__docformat__ = 'restructuredtext en'
+
+'''
+HTTP server for remote access to the calibre database.
+'''
+
+import sys
+from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler
+
+from calibre.constants import __version__
+
+class Server(HTTPServer):
+    pass
+
+class DBHandler(BaseHTTPRequestHandler):
+    
+    server_version = 'calibre/'+__version__
+    
+    def set_db(self, db):
+        self.db = db
+        
+    
+def server(db, port=80):
+    server = Server(('', port), DBHandler)
+
+def main(args=sys.argv):
+    from calibre.utils.config import prefs
+    from calibre.library.database2 import LibraryDatabase2
+    db = LibraryDatabase2(prefs['library_path'])
+    try:
+        print 'Starting server...'
+        s = server()
+        s.server_forever()
+    except KeyboardInterrupt:
+        print 'Server interrupted'
+        s.socket.close()
+    return 0
+
+if __name__ == '__main__':
+    sys.exit(main())
\ No newline at end of file
diff --git a/src/calibre/library/sqlite.py b/src/calibre/library/sqlite.py
new file mode 100644
index 0000000000..15d85dd362
--- /dev/null
+++ b/src/calibre/library/sqlite.py
@@ -0,0 +1,156 @@
+from __future__ import with_statement
+__license__   = 'GPL v3'
+__copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
+__docformat__ = 'restructuredtext en'
+
+'''
+Wrapper for multi-threaded access to a single sqlite database connection. Serializes
+all calls.
+'''
+import sqlite3 as sqlite, traceback, re, time
+from sqlite3 import IntegrityError
+from threading import Thread
+from Queue import Queue
+
+
+class Concatenate(object):
+    '''String concatenation aggregator for sqlite'''
+    def __init__(self, sep=','):
+        self.sep = sep
+        self.ans = ''
+        
+    def step(self, value):
+        if value is not None:
+            self.ans += value + self.sep
+    
+    def finalize(self):
+        if not self.ans:
+            return None
+        if self.sep:
+            return self.ans[:-len(self.sep)]
+        return self.ans
+
+class Connection(sqlite.Connection):
+    
+    def get(self, *args, **kw):
+        ans = self.execute(*args)
+        if not kw.get('all', True):
+            ans = ans.fetchone()
+            if not ans:
+                ans = [None]
+            return ans[0]
+        return ans.fetchall()
+ 
+
+class DBThread(Thread):
+    
+    CLOSE = '-------close---------'
+    
+    def __init__(self, path, row_factory):
+        Thread.__init__(self)
+        self.setDaemon(True)
+        self.path = path
+        self.unhandled_error = (None, '')
+        self.row_factory = row_factory
+        self.requests = Queue(1)
+        self.results  = Queue(1)
+        self.conn = None
+        
+    def connect(self):
+        self.conn = sqlite.connect(self.path, factory=Connection, 
+                                   detect_types=sqlite.PARSE_DECLTYPES|sqlite.PARSE_COLNAMES)
+        self.conn.row_factory = sqlite.Row if self.row_factory else  lambda cursor, row : list(row)
+        self.conn.create_aggregate('concat', 1, Concatenate)
+        title_pat = re.compile('^(A|The|An)\s+', re.IGNORECASE)
+        
+        def title_sort(title):
+            match = title_pat.search(title)
+            if match:
+                prep = match.group(1)
+                title = title.replace(prep, '') + ', ' + prep
+            return title.strip()
+    
+        self.conn.create_function('title_sort', 1, title_sort)
+    
+    def run(self):
+        try:
+            self.connect()
+            while True:
+                func, args, kwargs = self.requests.get()
+                if func == self.CLOSE:
+                    self.conn.close()
+                    break
+                func = getattr(self.conn, func)
+                try:
+                    ok, res = True, func(*args, **kwargs)
+                except Exception, err:
+                    ok, res = False, (err, traceback.format_exc())
+                self.results.put((ok, res))
+        except Exception, err:
+            self.unhandled_error = (err, traceback.format_exc())
+
+class DatabaseException(Exception):
+    
+    def __init__(self, err, tb):
+        tb = '\n\t'.join(('\tRemote'+tb).splitlines())
+        msg = unicode(err) +'\n' + tb
+        Exception.__init__(self, msg)
+        self.orig_err = err
+        self.orig_tb  = tb
+
+def proxy(fn):
+    ''' Decorator to call methods on the database connection in the proxy thread '''
+    def run(self, *args, **kwargs):
+        if self.proxy.unhandled_error[0] is not None:
+            raise DatabaseException(*self.proxy.unhandled_error)
+        self.proxy.requests.put((fn.__name__, args, kwargs))
+        ok, res = self.proxy.results.get()
+        if not ok:
+            if isinstance(res[0], IntegrityError):
+                raise IntegrityError(unicode(res[0]))
+            raise DatabaseException(*res)
+        return res
+    return run
+            
+
+class ConnectionProxy(object):
+    
+    def __init__(self, proxy):
+        self.proxy = proxy
+    
+    def close(self):
+        if self.proxy.unhandled_error is None:
+            self.proxy.requests.put((self.proxy.CLOSE, [], {}))
+    
+    @proxy
+    def get(self, query, all=True): pass
+    
+    @proxy        
+    def commit(self): pass
+    
+    @proxy
+    def execute(self): pass
+    
+    @proxy
+    def executemany(self): pass
+    
+    @proxy
+    def executescript(self): pass
+    
+    @proxy
+    def create_aggregate(self): pass
+    
+    @proxy
+    def create_function(self): pass
+    
+    @proxy
+    def cursor(self): pass
+    
+def connect(dbpath, row_factory=None):
+    conn = ConnectionProxy(DBThread(dbpath, row_factory))
+    conn.proxy.start()
+    while conn.proxy.unhandled_error[0] is None and conn.proxy.conn is None:
+        time.sleep(0.01)
+    if conn.proxy.unhandled_error[0] is not None:
+        raise DatabaseException(*conn.proxy.unhandled_error)
+    return conn
\ No newline at end of file
diff --git a/src/calibre/library/test.py b/src/calibre/library/test.py
new file mode 100644
index 0000000000..3065e4eec0
--- /dev/null
+++ b/src/calibre/library/test.py
@@ -0,0 +1,90 @@
+#!/usr/bin/env  python
+__license__   = 'GPL v3'
+__copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
+__docformat__ = 'restructuredtext en'
+
+'''
+Unit tests for database layer.
+'''
+
+import sys, unittest, os
+from itertools import repeat
+
+from calibre.ptempfile import PersistentTemporaryDirectory
+from calibre.library.database2 import LibraryDatabase2
+from calibre.ebooks.metadata import MetaInformation
+
+class DBTest(unittest.TestCase):
+    
+    img = '\xff\xd8\xff\xe0\x00\x10JFIF\x00\x01\x01\x01\x00d\x00d\x00\x00\xff\xdb\x00C\x00\x05\x03\x04\x04\x04\x03\x05\x04\x04\x04\x05\x05\x05\x06\x07\x0c\x08\x07\x07\x07\x07\x0f\x0b\x0b\t\x0c\x11\x0f\x12\x12\x11\x0f\x11\x11\x13\x16\x1c\x17\x13\x14\x1a\x15\x11\x11\x18!\x18\x1a\x1d\x1d\x1f\x1f\x1f\x13\x17"$"\x1e$\x1c\x1e\x1f\x1e\xff\xdb\x00C\x01\x05\x05\x05\x07\x06\x07\x0e\x08\x08\x0e\x1e\x14\x11\x14\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\x1e\xff\xc0\x00\x11\x08\x00\x01\x00\x01\x03\x01\x11\x00\x02\x11\x01\x03\x11\x01\xff\xc4\x00\x14\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\xff\xc4\x00\x14\x10\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xc4\x00\x14\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x06\xff\xc4\x00\x14\x11\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xff\xda\x00\x0c\x03\x01\x00\x02\x11\x03\x11\x00?\x00p\xf9+\xff\xd9'
+    
+    def setUp(self):
+        self.tdir    = PersistentTemporaryDirectory('_calibre_dbtest')
+        self.db      = LibraryDatabase2(self.tdir)
+        f = open(os.path.join(self.tdir, 'test.txt'), 'w+b')
+        f.write('test')
+        paths = list(repeat(f, 3))
+        formats = list(repeat('txt', 3))
+        m1 = MetaInformation('Test Ebook 1', ['Test Author 1'])
+        m1.tags = ['tag1', 'tag2']
+        m1.publisher = 'Test Publisher 1'
+        m1.rating = 2
+        m1.series = 'Test Series 1'
+        m1.series_index = 3
+        m1.author_sort = 'as1'
+        m1.isbn = 'isbn1'
+        m1.cover_data = ('jpg', self.img)
+        m2 = MetaInformation('Test Ebook 2', ['Test Author 2'])
+        m2.tags = ['tag3', 'tag4']
+        m2.publisher = 'Test Publisher 2'
+        m2.rating = 3
+        m2.series = 'Test Series 2'
+        m2.series_index = 1
+        m2.author_sort = 'as1'
+        m2.isbn = 'isbn1'
+        self.db.add_books(paths, formats, [m1, m2, m2], add_duplicates=True)
+        self.m1, self.m2 = m1, m2
+        
+    def testAdding(self):
+        m1, m2 = self.db.get_metadata(1, True), self.db.get_metadata(2, True)
+        for p in ('title', 'authors', 'publisher', 'rating', 'series', 
+                  'series_index', 'author_sort', 'isbn', 'tags'):
+            
+            def ga(mi, p):
+                val = getattr(mi, p)
+                if isinstance(val, list):
+                    val = set(val)
+                return val
+            
+            self.assertEqual(ga(self.m1, p), ga(m1, p))
+            self.assertEqual(ga(self.m2, p), ga(m2, p))
+        
+        self.assertEqual(self.db.format(1, 'txt', index_is_id=True), 'test')
+        self.assertNotEqual(self.db.cover(1, index_is_id=True), None)
+        self.assertEqual(self.db.cover(2, index_is_id=True), None)
+        
+    def testMetadata(self):
+        self.db.refresh('timestamp', True)
+        for x in ('title', 'author_sort', 'series', 'publisher', 'isbn', 'series_index', 'rating'):
+            val = 3 if x in ['rating', 'series_index'] else 'dummy'
+            getattr(self.db, 'set_'+x)(3, val)
+            self.db.refresh_ids([3])
+            self.assertEqual(getattr(self.db, x)(2), val)
+            
+        self.db.set_authors(3, ['new auth'])
+        self.assertEqual(self.db.format(3, 'txt', index_is_id=True), 'test')
+        
+    
+def suite():
+    return unittest.TestLoader().loadTestsFromTestCase(DBTest)
+    
+def test():
+    unittest.TextTestRunner(verbosity=2).run(suite())
+
+
+def main(args=sys.argv):
+    test()
+    return 0
+
+if __name__ == '__main__':
+    sys.exit(main())
\ No newline at end of file