index 56121b91f8f5c969e8f8262f871a2890b3168bde..517adc9d51de26bcedea0a6c28ccbf9e1c1a2bb6 100644 (file)
<!--
-$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.83 2005年12月29日 04:02:32 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.84 2006年02月05日 02:47:53 momjian Exp $
-->
<chapter id="plpgsql">
@@ -3007,16 +3007,17 @@ CREATE OR REPLACE FUNCTION maint_sales_summary_bytime() RETURNS TRIGGER AS $main
END IF;
- -- Update the summary row with the new values.
- UPDATE sales_summary_bytime
- SET amount_sold = amount_sold + delta_amount_sold,
- units_sold = units_sold + delta_units_sold,
- amount_cost = amount_cost + delta_amount_cost
- WHERE time_key = delta_time_key;
+ -- Insert or update the summary row with the new values.
+ <<insert_update>>
+ LOOP
+ UPDATE sales_summary_bytime
+ SET amount_sold = amount_sold + delta_amount_sold,
+ units_sold = units_sold + delta_units_sold,
+ amount_cost = amount_cost + delta_amount_cost
+ WHERE time_key = delta_time_key;
+ EXIT insert_update WHEN found;
- -- There might have been no row with this time_key (e.g new data!).
- IF (NOT FOUND) THEN
BEGIN
INSERT INTO sales_summary_bytime (
time_key,
@@ -3029,20 +3030,15 @@ CREATE OR REPLACE FUNCTION maint_sales_summary_bytime() RETURNS TRIGGER AS $main
delta_units_sold,
delta_amount_cost
);
+
+ EXIT insert_update;
+
EXCEPTION
- --
- -- Catch race condition when two transactions are adding data
- -- for a new time_key.
- --
WHEN UNIQUE_VIOLATION THEN
- UPDATE sales_summary_bytime
- SET amount_sold = amount_sold + delta_amount_sold,
- units_sold = units_sold + delta_units_sold,
- amount_cost = amount_cost + delta_amount_cost
- WHERE time_key = delta_time_key;
-
+ -- do nothing
END;
- END IF;
+ END LOOP insert_update;
+
RETURN NULL;
END;
CREATE TRIGGER maint_sales_summary_bytime
AFTER INSERT OR UPDATE OR DELETE ON sales_fact
FOR EACH ROW EXECUTE PROCEDURE maint_sales_summary_bytime();
+
+INSERT INTO sales_fact VALUES(1,1,1,10,3,15);
+INSERT INTO sales_fact VALUES(1,2,1,20,5,35);
+INSERT INTO sales_fact VALUES(2,2,1,40,15,135);
+INSERT INTO sales_fact VALUES(2,3,1,10,1,13);
+SELECT * FROM sales_summary_bytime;
+DELETE FROM sales_fact WHERE product_key = 1;
+SELECT * FROM sales_summary_bytime;
+UPDATE sales_fact SET units_sold = units_sold * 2;
+SELECT * FROM sales_summary_bytime;
</programlisting>
</example>