-- these triggers are dedicated to HPHC of RI who
-- decided that my kid's name was william not willem, and
-- vigorously resisted all efforts at correction.  they have
-- since gone bankrupt...
CREATE FUNCTION users_insert() returns trigger
	AS
'if TD["new"]["fname"] == None or TD["new"]["lname"] == None:
	return "SKIP"
if TD["new"]["username"] == None:
	TD["new"]["username"] = TD["new"]["fname"][:1] + "_" + TD["new"]["lname"]
	rv = "MODIFY"
else:
	rv = None
if TD["new"]["fname"] == "william":
	TD["new"]["fname"] = TD["args"][0]
	rv = "MODIFY"
return rv'
	LANGUAGE plpythonu;
CREATE FUNCTION users_update() returns trigger
	AS
'if TD["event"] == "UPDATE":
	if TD["old"]["fname"] != TD["new"]["fname"] and TD["old"]["fname"] == TD["args"][0]:
		return "SKIP"
return None'
	LANGUAGE plpythonu;
CREATE FUNCTION users_delete() RETURNS trigger
	AS
'if TD["old"]["fname"] == TD["args"][0]:
	return "SKIP"
return None'
	LANGUAGE plpythonu;
CREATE TRIGGER users_insert_trig BEFORE INSERT ON users FOR EACH ROW
	EXECUTE PROCEDURE users_insert ('willem');
CREATE TRIGGER users_update_trig BEFORE UPDATE ON users FOR EACH ROW
	EXECUTE PROCEDURE users_update ('willem');
CREATE TRIGGER users_delete_trig BEFORE DELETE ON users FOR EACH ROW
	EXECUTE PROCEDURE users_delete ('willem');
-- quick peek at the table
--
SELECT * FROM users;
 fname  | lname | username | userid 
--------+-------+----------+--------
 jane   | doe   | j_doe    |      1
 john   | doe   | johnd    |      2
 willem | doe   | w_doe    |      3
 rick   | smith | slash    |      4
(4 rows)

-- should fail
--
UPDATE users SET fname = 'william' WHERE fname = 'willem';
-- should modify william to willem and create username
--
INSERT INTO users (fname, lname) VALUES ('william', 'smith');
INSERT INTO users (fname, lname, username) VALUES ('charles', 'darwin', 'beagle');
SELECT * FROM users;
  fname  | lname  | username | userid 
---------+--------+----------+--------
 jane    | doe    | j_doe    |      1
 john    | doe    | johnd    |      2
 willem  | doe    | w_doe    |      3
 rick    | smith  | slash    |      4
 willem  | smith  | w_smith  |      5
 charles | darwin | beagle   |      6
(6 rows)

-- dump trigger data
CREATE TABLE trigger_test
	(i int, v text );
CREATE FUNCTION trigger_data() returns trigger language plpythonu as $$

if TD.has_key('relid'):
	TD['relid'] = "bogus:12345"

skeys = TD.keys()
skeys.sort()
for key in skeys:
	val = TD[key]
	plpy.notice("TD[" + key + "] => " + str(val))

return None  

$$;
CREATE TRIGGER show_trigger_data_trig 
BEFORE INSERT OR UPDATE OR DELETE ON trigger_test
FOR EACH ROW EXECUTE PROCEDURE trigger_data(23,'skidoo');
insert into trigger_test values(1,'insert');
NOTICE:  ("TD[args] => ['23', 'skidoo']",)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[event] => INSERT',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[level] => ROW',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[name] => show_trigger_data_trig',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ("TD[new] => {'i': 1, 'v': 'insert'}",)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[old] => None',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[relid] => bogus:12345',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[table_name] => trigger_test',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[table_schema] => public',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[when] => BEFORE',)
CONTEXT:  PL/Python function "trigger_data"
update trigger_test set v = 'update' where i = 1;
NOTICE:  ("TD[args] => ['23', 'skidoo']",)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[event] => UPDATE',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[level] => ROW',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[name] => show_trigger_data_trig',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ("TD[new] => {'i': 1, 'v': 'update'}",)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ("TD[old] => {'i': 1, 'v': 'insert'}",)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[relid] => bogus:12345',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[table_name] => trigger_test',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[table_schema] => public',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[when] => BEFORE',)
CONTEXT:  PL/Python function "trigger_data"
delete from trigger_test;
NOTICE:  ("TD[args] => ['23', 'skidoo']",)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[event] => DELETE',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[level] => ROW',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[name] => show_trigger_data_trig',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[new] => None',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ("TD[old] => {'i': 1, 'v': 'update'}",)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[relid] => bogus:12345',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[table_name] => trigger_test',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[table_schema] => public',)
CONTEXT:  PL/Python function "trigger_data"
NOTICE:  ('TD[when] => BEFORE',)
CONTEXT:  PL/Python function "trigger_data"
      
DROP TRIGGER show_trigger_data_trig on trigger_test;
      
DROP FUNCTION trigger_data();