Reset event serial ids after re-import.

When the database is recreated, the sequences
used in the events_timed and events_seq tables
will be at their initial values, which will
almost certainly conflict with existing data
when it is imported via COPY.

With this commit, we set the current value for
those sequences to something usable.

Fixes #33.

bin/system_imports.py

@@ -46,5 +46,7 @@ if __name__ == '__main__':
 
 			# If we don't commit the data does not actually get copied
 			db.conn.commit()
+			# Update the sequences that generate event ids
+			cur.execute("SELECT reset_events_serials();")
 
 	print("Done")

etc/db/schema-template.sql

@@ -90,6 +90,22 @@ All values are returned as being of type "text" and need casting before use.
 ';
 
 
+--
+-- Name: reset_events_serials(); Type: FUNCTION; Schema: _SURVEY__TEMPLATE_; Owner: postgres
+--
+
+CREATE FUNCTION _SURVEY__TEMPLATE_.reset_events_serials() RETURNS void
+    LANGUAGE plpgsql
+    AS $$
+BEGIN
+PERFORM setval('events_timed_id_seq', (SELECT max(id)+1 FROM events_timed));
+PERFORM setval('events_seq_id_seq', (SELECT max(id)+1 FROM events_seq));
+END;
+$$;
+
+
+ALTER FUNCTION _SURVEY__TEMPLATE_.reset_events_serials() OWNER TO postgres;
+
 --
 -- Name: to_binning_grid(public.geometry); Type: FUNCTION; Schema: _SURVEY__TEMPLATE_; Owner: postgres
 --