-- table to hold site arrays
CREATE TABLE site (
	id_site serial,
	site text[] NOT NULL
);

ALTER TABLE ONLY site
	ADD CONSTRAINT id_site PRIMARY KEY (id_site);
	ADD CONSTRAINT site_pkey PRIMARY KEY (id_site);

CREATE UNIQUE INDEX site_s ON site (usort(site));
CREATE UNIQUE INDEX site_u ON site (usort(site));

CREATE INDEX site_g ON site USING gin (site);

-- table to hold tag combinations
CREATE TABLE tag (
	id_tag serial,
	tag text[] NOT NULL
);

ALTER TABLE ONLY tag
	ADD CONSTRAINT tag_id PRIMARY KEY (id_tag);
	ADD CONSTRAINT tag_pkey PRIMARY KEY (id_tag);

CREATE UNIQUE INDEX tag_s ON tag (usort(tag));
CREATE UNIQUE INDEX tag_u ON tag (usort(tag));

CREATE INDEX tag_g ON tag USING gin (tag);

-- table to hold tag - site links
CREATE TABLE urls (
	date_added timestamp without time zone DEFAULT ('now'::text)::timestamp(0) without time zone NOT NULL,
	id_site smallint NOT NULL,