TABLES
	alert_codes 
	(
	alert_type_cd varchar(5) NOT NULL,
	alert_description varchar(50),
	CONSTRAINT alerts_pk PRIMARY KEY (alert_type_cd)
	);

	customers
	(
	cust_id	serial NOT NULL,
	cust_name varchar(30),
	CONSTRAINT customers_pk PRIMARY KEY(cust_id)
	);
	
	locations
	(
	cust_id bigint NOT NULL,
	location_id serial NOT NULL,
	location_desc varchar(50) NOT NULL,
	location_city varchar(40) NOT NULL,
	CONSTRAINT locations_pk PRIMARY KEY (cust_id, location_id)
	);
	
	equipment
	(
	cust_id bigint NOT NULL,
	equipment_id varchar(20) NOT NULL,
	equipment_desc varchar(50),
	CONSTRAINT equipment_pk PRIMARY KEY (cust_id, equipment_id),
	CONSTRAINT fk_equip_cust FOREIGN KEY (cust_id)
		REFERENCES customers(cust_id),
	CONSTRAINT fk_equip_loc FOREIGN KEY (location_id)
		REFERENCES locations(location_id)
	);
	
	alerts
	(alert_id serial NOT NULL,
	 cust_id bigint NOT NULL,
	 location_id bigint NOT NULL,
	 equipment_id varchar(20) NOT NULL,
	 alert_type_cd varchar(5) NOT NULL,
	 alert_time timestamp NOT NULL,
	 CONSTRAINT alerts_pk PRIMARY KEY (alert_id),
	 CONSTRAINT fk_alerts_cust FOREIGN KEY (cust_id)
		REFERENCES customers(cust_id),
	 CONSTRAINT fk_equip_cust FOREIGN KEY (cust_id)
		REFERENCES customers(cust_id),
	 CONSTRAINT fk_equip_loc FOREIGN KEY (location_id)
		REFERENCES locations(location_id),
	 CONSTRAINT fk_equip FOREIGN KEY (equipment_id)
		REFERENCES equipment(equipment_id)
	);
	
	schedule
	(
	cust_id bigint NOT NULL,
	equipment_id varchar(20) NOT NULL,
	activedays varchar(5)  NOT NULL,  -- AD = all days, WD = mon-fri, Mn,Tu,Wd,Th,Fr
	active_start timestamp NOT NULL,
	active_end timestamp NOT NULL,
	CONSTRAINT fk_sched_cust FOREIGN KEY (cust_id)
		REFERENCES customers(cust_id),
	CONSTRAINT fk_equip FOREIGN KEY (equipment_id)
		REFERENCES equipment(equipment_id)
	);
	
	holidays
	(
	cust_id bigint NOT NULL,
	location_id bigint NOT NULL,
	holiday date NOT NULL,
	CONSTRAINT holiday_pk PRIMARY KEY (cust_id, location_id, holiday)
	);