From 9aeac925415d728c897519bc8e435777a9328a97 Mon Sep 17 00:00:00 2001
From: chmnata <chmnata@gmail.com>
Date: Thu, 15 Feb 2024 21:36:07 +0000
Subject: [PATCH] #801 add latest mat view and trigger function

---
 .../sql/create_matview_centreline_latest.sql  | 19 +++++++++++++++++++
 .../sql/create_trigger_centreline_latest.sql  | 18 ++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 gis/centreline/sql/create_matview_centreline_latest.sql
 create mode 100644 gis/centreline/sql/create_trigger_centreline_latest.sql

diff --git a/gis/centreline/sql/create_matview_centreline_latest.sql b/gis/centreline/sql/create_matview_centreline_latest.sql
new file mode 100644
index 000000000..b126bd550
--- /dev/null
+++ b/gis/centreline/sql/create_matview_centreline_latest.sql
@@ -0,0 +1,19 @@
+CREATE MATERIALIZED VIEW gis_core.centreline_latest AS 
+SELECT *
+FROM gis_core.centreline
+WHERE version_date = (SELECT MAX(version_date) FROM gis_core.centreline); 
+
+CREATE TRIGGER refresh_trigger
+        AFTER INSERT OR UPDATE OR DELETE
+        ON gis_core.centreline
+        FOR EACH STATEMENT
+        EXECUTE PROCEDURE gis_core.centreline_latest_trigger(); 
+
+CREATE INDEX gis_core_centreline_latest_geom
+    ON gis_core.centreline_latest USING gist(geom);
+	
+ALTER MATERIALIZED VIEW gis_core.centreline_latest OWNER TO gis_admins;
+
+GRANT SELECT ON gis_core.centreline_latest TO bdit_humans;
+
+COMMENT ON MATERIALIZED VIEW gis_core.centreline_latest IS 'Materialized view containing the latest version of centreline, derived from gis_core.centreline.'
\ No newline at end of file
diff --git a/gis/centreline/sql/create_trigger_centreline_latest.sql b/gis/centreline/sql/create_trigger_centreline_latest.sql
new file mode 100644
index 000000000..a7641c8ac
--- /dev/null
+++ b/gis/centreline/sql/create_trigger_centreline_latest.sql
@@ -0,0 +1,18 @@
+CREATE OR REPLACE FUNCTION gis_core.centreline_latest_trigger()
+    RETURNS trigger 
+    LANGUAGE 'plpgsql'
+    COST 100
+    VOLATILE NOT LEAKPROOF SECURITY DEFINER
+AS $BODY$
+BEGIN
+
+REFRESH MATERIALIZED VIEW gis_core.centreline_latest;
+RETURN NULL;
+
+END;
+$BODY$;
+
+ALTER FUNCTION gis_core.centreline_latest_trigger() OWNER TO gis_admins;
+
+COMMENT ON FUNCTION gis_core.centreline_latest_trigger() IS 'Trigger fuction that refreshes the centreline_latest mat view after an update.';
+