Initial materialized views and triggers

layers/water_name/water_lakeline.sql

@@ -1,9 +1,7 @@
 
-DROP TABLE IF EXISTS osm_water_lakeline CASCADE;
-
 -- etldoc:  osm_water_polygon ->  osm_water_lakeline
 -- etldoc:  lake_centerline  ->  osm_water_lakeline
-CREATE TABLE IF NOT EXISTS osm_water_lakeline AS (
+CREATE MATERIALIZED VIEW osm_water_lakeline AS (
 	SELECT wp.osm_id,
 		ll.wkb_geometry AS geometry,
 		name, name_en, ST_Area(wp.geometry) AS area
@@ -11,5 +9,20 @@ CREATE TABLE IF NOT EXISTS osm_water_lakeline AS (
     INNER JOIN lake_centerline ll ON wp.osm_id = ll.osm_id
     WHERE wp.name <> ''
 );
-
 CREATE INDEX IF NOT EXISTS osm_water_lakeline_geometry_idx ON osm_water_lakeline USING gist(geometry);
+
+-- Triggers
+
+CREATE OR REPLACE FUNCTION refresh_osm_water_lakeline() RETURNS trigger AS
+  $BODY$
+  BEGIN
+    REFRESH MATERIALIZED VIEW osm_water_lakeline CONCURRENTLY;
+      RETURN null;
+  END;
+  $BODY$
+language plpgsql
+
+CREATE TRIGGER trigger_refresh_osm_water_lakeline
+    AFTER INSERT OR UPDATE OR DELETE ON osm_water_polygon
+    FOR EACH STATEMENT
+    EXECUTE PROCEDURE refresh_osm_water_lakeline