diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index 122e8c627f..bc503aef08 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -1320,7 +1320,6 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         if name:
             if not replace:
                 return False
-            self.conn.execute('DELETE FROM data WHERE book=? AND format=?', (id, format))
         name = self.construct_file_name(id)
         ext = ('.' + format.lower()) if format else ''
         dest = os.path.join(path, name+ext)
@@ -1333,7 +1332,7 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
                 shutil.copyfileobj(stream, f)
         stream.seek(0, 2)
         size=stream.tell()
-        self.conn.execute('INSERT INTO data (book,format,uncompressed_size,name) VALUES (?,?,?,?)',
+        self.conn.execute('INSERT OR REPLACE INTO data (book,format,uncompressed_size,name) VALUES (?,?,?,?)',
                           (id, format.upper(), size, name))
         self.conn.commit()
         self.refresh_ids([id])