Hello,
I have a question about inherited tables w/r to triggers... Hopefully
this will make some sense... (I'll try to keep the schema example as
simple as possible):
Given the follow schema/tables:
-- public stuff
SET search_path = public, pg_catalog;
CREATE TABLE customer(
customer_id SERIAL,
customer_notification INTEGER,
CONSTRAINT customer_notification CHECK ((((notification = 0) OR
(notification = 1)) OR (notification = 2))),
);
CREATE TABLE shipto (
trans_id INTEGER
);
CREATE FUNCTION del_customer() RETURNS "trigger"
AS '
begin
delete from shipto where trans_id = old.id;
return NULL;
end;
'
LANGUAGE plpgsql;
-- test schema
CREATE SCHEMA test;
SET search_path = test, pg_catalog;
CREATE TABLE customer () INHERITS (public.customer);
CREATE TABLE proposals (
proposal_id PRIMARY KEY,
user_id INTEGER REFERENCES customer(name)
);
-- test2 schema
CREATE SCHEMA test2;
SET search_path = test2, pg_catalog;
CREATE TABLE customer () INHERITS (test.customer);
CREATE TABLE proposals () INHERITS (test.proposals);
Here are some questions:
#1. With regards to inserts/update/deletes on test.customer and
test2.customer, will the trigger on public.customer fire? In this case
the shipto table does not exist in either schema test or test2, but I
need to make sure the trigger will fire when modifications are made to
the customer table in those schemas.
#2. Will inserts on the inherited table increment the user_id in the
public.customer table? (I'm fairly sure that it will, just wnat to be
certain.)
#3. With regards to the constraint, will it applied to the inherited
tables (I.E. only able to insert customer_notification when it contains a
value of 0, 1, or 2?) (I am fairly certain it will, but want to be sure!)
#4. This is where I get really confused.. :-( With regards to the
REFERENCES customer(name), does this apply to test2.proposals with
regards to the test2.customer table? Would it be possible to insert a
proposal that contained a user_id contained in test.customer, but not
test2.customer?.... I just don't understand the documentation on this
issue of foreign keys and what is actually inherited...
Is there someplace I can look for a more thorough explanation of how
postgres handles inheritance?
Thanks as always!
- Greg
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