Technology dependencies view

* Added SQL view that lists dependencies of technologies as
comma-separated lists of identifiers

legacyworlds-server-data/db-structure/parts/040-functions/026-technology-dependencies.sql

@@ -311,4 +311,27 @@ CREATE TRIGGER tg_techdeps_ai
 
 REVOKE EXECUTE
 	ON FUNCTION defs.tgf_techdeps_ai( )
-	FROM PUBLIC;
+	FROM PUBLIC;
+
+
+/*
+ * Technology dependencies view
+ * -----------------------------
+ * 
+ * This view generates a parseable list of dependencies per technology.
+ * 
+ * Columns:
+ *		technology_name_id		The technology's name
+ *		technology_dependencies	A list of comma-separated technology name
+ *									identifiers
+ */
+DROP VIEW IF EXISTS defs.technology_dependencies_view CASCADE;
+CREATE VIEW defs.technology_dependencies_view
+	AS SELECT technology_name_id ,
+			array_to_string( array_agg( _name_str.name ) , ',' ) AS technology_dependencies
+		FROM defs.technologies _tech
+			LEFT OUTER JOIN defs.technology_dependencies
+				USING ( technology_name_id )
+			LEFT OUTER JOIN defs.strings _name_str
+				ON _name_str.id = technology_name_id_depends
+		GROUP BY technology_name_id;