Add database schema

diff --git a/m_librarian/db.py b/m_librarian/db.py
new file mode 100755 (executable)
index 0000000..e78f8f1
--- /dev/null
+++ b/m_librarian/db.py
@@ -0,0 +1,62 @@
+#! /usr/bin/env python
+
+import os
+from sqlobject import SQLObject, StringCol, UnicodeCol, IntCol, \
+    connectionForURI, sqlhub
+from .config import ml_conf
+
+try:
+    db_uri = ml_conf.get('database', 'URI')
+except:
+    db_uri = None
+
+db_dirs = []
+if not db_uri:
+    if 'XDG_CACHE_HOME' in os.environ:
+        db_dirs.append(os.environ['XDG_CACHE_HOME'])
+    home_cache = os.path.expanduser('~/.cache')
+    if home_cache not in db_dirs:
+        db_dirs.append(home_cache)
+
+    for d in db_dirs:
+        db_file = os.path.join(d, 'm_librarian.sqlite')
+        if os.path.exists(db_file):
+            break
+    else:
+        # octal; -rw-------;
+        # make the database file/directory readable/writeable only by the user
+        os.umask(0066)
+        db_dir = db_dirs[0]
+        try:
+            os.makedirs(db_dir)
+        except OSError:  # Perhaps already exists
+            pass
+        db_file = os.path.join(db_dir, 'm_librarian.sqlite')
+        db_uri = 'sqlite://%s' % db_file.replace(os.sep, '/')
+
+sqlhub.processConnection = connectionForURI(db_uri)
+
+
+class Author(SQLObject):
+    name = UnicodeCol()
+    count = IntCol()
+
+
+class Book(SQLObject):
+    name = UnicodeCol()
+
+
+class Extension(SQLObject):
+    name = StringCol()
+    count = IntCol()
+
+
+class Language(SQLObject):
+    name = StringCol()
+    count = IntCol()
+
+
+if __name__ == '__main__':
+    print "DB dirs:", db_dirs
+    if db_uri:
+        print "DB URI:", db_uri