PostgreSQLでCodeigniterを使う場合のセッションテーブルを作るSQL

CREATE TABLE ci_sessions
(
 session_id character varying(40) NOT NULL DEFAULT 0,
 ip_address character varying(16) NOT NULL DEFAULT 0,
 user_agent character varying(120) NOT NULL,
 last_activity integer NOT NULL DEFAULT 0,
 user_data text NOT NULL,
 CONSTRAINT ci_sessions_pkey PRIMARY KEY (session_id)
)
WITH (
 OIDS=FALSE
);
ALTER TABLE ci_sessions
 OWNER TO postgres;
COMMENT ON TABLE ci_sessions
 IS 'セッション情報を格納';
CREATE INDEX ci_sessions_last_activity_idx
ON ci_sessions
 USING btree
 (last_activity);