[SQL] Referencing a view?

[James Orr]

Hi,   Is there anyway that you can reference a column in a view for referential integrity?  The problem is with the unique thing, obviously I can't create a unique index on a view.  Here is what I have: CREATE SEQUENCE "addresses_id_seq" start 1 increment 1 maxvalue 2147483647 minvalue 1  cache 1 ;   CREATE TABLE "org_addresses" (  "id" integer DEFAULT nextval('addresses_id_seq'::text) NOT NULL,  "orgid" integer references orgs on delete cascade,  "name" character varying(255),  "street1" character varying(255),  "street2" character varying(100),  "city" character varying(100),  "state" character(2),  "zip" character(10),  Constraint "org_addresses_pkey" Primary Key ("id") );   CREATE TABLE "user_addresses" (  "id" integer DEFAULT nextval('addresses_id_seq'::text) NOT NULL,  "userid" integer references users on delete cascade,  "name" character varying(255),  "street1" character varying(255),  "street2" character varying(100),  "city" character varying(100),  "state" character(2),  "zip" character(10),  Constraint "user_addresses_pkey" Primary Key ("id") );   CREATE VIEW "addresses" as SELECT user_addresses.id, user_addresses.userid, user_addresses.name, user_addresses.street1, user_addresses.street2, user_addresses.city, user_addresses.state, user_addresses.zip FROM user_addresses UNION SELECT org_addresses.id, NULL::unknown, org_addresses.name, org_addresses.street1, org_addresses.street2, org_addresses.city, org_addresses.state, org_addresses.zip FROM org_addresses; So this gives me a view with every address, each with a unique id as I used the same sequence in both tables.  Now what I want to do is something like this :   CREATE TABLE orders (     id serial primary key,     shipping_address int references addresses(id), . . );   Which of course doesn't work because addresses as a view can't have a unique index.  Any way around this?   - James