diff --git a/dba/patches/1.2.1.sql b/dba/patches/1.2.1.sql
new file mode 100644
index 00000000..60e7ac73
--- /dev/null
+++ b/dba/patches/1.2.1.sql
@@ -0,0 +1,74 @@
+
+-- This database update provides new tables for the Principal, for
+-- a consistent dav_resource which a principal, collection or calendar_item
+-- all inherit from.
+
+BEGIN;
+SELECT check_db_revision(1,1,12);
+
+-- Rename the caldav_data_dav_id_seq to dav_id_seq because we will use it
+-- for more tables than just caldav_data
+CREATE SEQUENCE dav_id_seq;
+SELECT setval('dav_id_seq', nextval('caldav_data_dav_id_seq'));
+ALTER TABLE caldav_data ALTER COLUMN dav_id SET DEFAULT nextval('dav_id_seq');
+ALTER TABLE calendar_item ALTER COLUMN dav_id SET DEFAULT nextval('dav_id_seq');
+
+CREATE or REPLACE FUNCTION sync_dav_id ( ) RETURNS TRIGGER AS '
+  DECLARE
+  BEGIN
+
+    IF TG_OP = ''DELETE'' THEN
+      -- Just let the ON DELETE CASCADE handle this case
+      RETURN OLD;
+    END IF;
+
+    IF NEW.dav_id IS NULL THEN
+      NEW.dav_id = nextval(''dav_id_seq'');
+    END IF;
+
+    IF TG_OP = ''UPDATE'' THEN
+      IF OLD.dav_id = NEW.dav_id THEN
+        -- Nothing to do
+        RETURN NEW;
+      END IF;
+    END IF;
+
+    IF TG_RELNAME = ''caldav_data'' THEN
+      UPDATE calendar_item SET dav_id = NEW.dav_id WHERE user_no = NEW.user_no AND dav_name = NEW.dav_name;
+    ELSE
+      UPDATE caldav_data SET dav_id = NEW.dav_id WHERE user_no = NEW.user_no AND dav_name = NEW.dav_name;
+    END IF;
+
+    RETURN NEW;
+
+  END
+' LANGUAGE 'plpgsql';
+
+-- CREATE TRIGGER caldav_data_sync_dav_id AFTER INSERT OR UPDATE ON caldav_data
+--     FOR EACH ROW EXECUTE PROCEDURE sync_dav_id();
+
+-- CREATE TRIGGER calendar_item_sync_dav_id AFTER INSERT OR UPDATE ON calendar_item
+--     FOR EACH ROW EXECUTE PROCEDURE sync_dav_id();
+
+
+-- Add a numeric collection_id to collection
+ALTER TABLE collection ADD COLUMN collection_id INT8;
+UPDATE collection SET collection_id = nextval('dav_id_seq');
+ALTER TABLE collection ALTER COLUMN collection_id SET DEFAULT nextval('dav_id_seq');
+ALTER TABLE collection DROP CONSTRAINT collection_pkey CASCADE;
+ALTER TABLE collection ADD UNIQUE (user_no,dav_name);
+ALTER TABLE collection ADD CONSTRAINT collection_pkey PRIMARY KEY (collection_id);
+
+ALTER TABLE calendar_item ADD COLUMN collection_id INT8;
+UPDATE calendar_item SET collection_id = collection.collection_id
+          FROM collection WHERE collection.dav_name = regexp_replace( calendar_item.dav_name, '/[^/]+$', '/');
+ALTER TABLE calendar_item ALTER COLUMN collection_id SET NOT NULL;
+ALTER TABLE calendar_item ADD CONSTRAINT
+       calendar_item_collection_id_fkey FOREIGN KEY (collection_id) REFERENCES collection(collection_id);
+CREATE INDEX calendar_item_collection_id_fkey ON calendar_item(collection_id,user_no);
+
+SELECT new_db_revision(1,2,1, 'Janvier' );
+
+COMMIT;
+ROLLBACK;
+