Add 'DB/DBLab3/' from commit '5fc082aed9b5eb584269e5f3498fa35b669125b7'

git-subtree-dir: DB/DBLab3
git-subtree-mainline: 71fa30ebd9
git-subtree-split: 5fc082aed9

DB/DBLab3/trigger.sql

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+CREATE TYPE ftimes AS (creation_time DATE, disposal_time DATE);
+
+CREATE FUNCTION check_frames()
+RETURNS TRIGGER AS $$
+DECLARE
+	all_times ftimes[];
+	element ftimes;
+	flag BOOL := false;
+BEGIN
+	SELECT ARRAY(
+		SELECT DISTINCT row(frame.creation_time, frame.disposal_time)::ftimes FROM frame
+        	JOIN galaxy ON frame.galaxy_name = galaxy.galaxy_name
+        	JOIN nebula ON nebula.galaxy_name = galaxy.galaxy_name
+        	JOIN star ON star.nebula_name = nebula.nebula_name
+        	JOIN human ON human.passport_id = frame.human
+		WHERE NEW.star_name = star.star_name AND NEW.human = human.passport_id
+	) INTO all_times;
+
+	FOREACH element IN ARRAY all_times LOOP
+        	IF (NEW.collision_time BETWEEN element.creation_time AND element.disposal_time) THEN
+			flag = true;
+		END IF;
+    	END LOOP;
+
+	IF NOT flag AND (TG_OP = 'INSERT' OR TG_OP = 'UPDATE') THEN
+		RAISE EXCEPTION 'Запись не может быть создана или изменена, так как данное взаимодействие не было замечено в установленной раме';
+	END IF;
+
+	RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER register_collision_time
+BEFORE INSERT OR UPDATE ON star_collision
+FOR EACH ROW
+EXECUTE FUNCTION check_frames();
+
+