Make the sql rerunnable without error

layers/place/merge_state_rank.sql

@@ -3,7 +3,7 @@ ALTER TABLE osm_state_point DROP CONSTRAINT IF EXISTS osm_state_point_rank_const
 -- etldoc: ne_10m_admin_1_states_provinces_shp   -> osm_state_point
 -- etldoc: osm_state_point                       -> osm_state_point
 
-CREATE FUNCTION update_osm_state_point() RETURNS VOID AS $$
+CREATE OR REPLACE FUNCTION update_osm_state_point() RETURNS VOID AS $$
 BEGIN
 
   WITH important_state_point AS (
@@ -39,7 +39,7 @@ CREATE INDEX IF NOT EXISTS osm_state_point_rank_idx ON osm_state_point("rank");
 
 -- Handle updates
 
-CREATE SCHEMA place_state;
+CREATE SCHEMA IF NOT EXISTS place_state;
 
 CREATE TABLE IF NOT EXISTS place_state.updates(id serial primary key, t text, unique (t));
 CREATE OR REPLACE FUNCTION place_state.flag() RETURNS trigger AS $$
@@ -60,6 +60,9 @@ CREATE OR REPLACE FUNCTION place_state.refresh() RETURNS trigger AS
   $BODY$
 language plpgsql;
 
+DROP TRIGGER IF EXISTS trigger_flag ON osm_state_point;
+DROP TRIGGER IF EXISTS trigger_refresh ON place_state.updates;
+
 CREATE TRIGGER trigger_flag
     AFTER INSERT OR UPDATE OR DELETE ON osm_state_point
     FOR EACH STATEMENT