create table tags
(
	id integer not null primary key default nextval('public.documents_id_seq'::text),
	ctime timestamp not null default now(),
	mtime timestamp not null default now(),
	class text not null,
	status smallint not null default 0,
	sections integer,
	name text,
	alias text,
	data text
);
create index tags_name on tags (name);
create index tags_alias on tags (alias) WHERE alias IS NOT NULL AND alias != '';