Please ignore my previous message on this topic. The error was being raised by a trigger. My apologies for cluttering the list. RobR On Thursday, August 9, 2018, 3:07:03 PM EDT, Rob Richardson <interrob...@yahoo.com> wrote: Please see the attached image. As you can see, a not-null constraint error is being raised for a field that actually is not null. Please explain this. Here's the table definition: -- Table: public.alarm_history -- DROP TABLE public.alarm_history; CREATE TABLE public.alarm_history( alarm_history_pkey bigint NOT NULL, area character varying(32) COLLATE pg_catalog."default" NOT NULL DEFAULT 'All'::character varying, device character varying(32) COLLATE pg_catalog."default", alarm_number smallint NOT NULL DEFAULT 0, tag character varying(32) COLLATE pg_catalog."default", state smallint NOT NULL, message text COLLATE pg_catalog."default", alarm_date timestamp with time zone, charge integer, ack_date timestamp with time zone, ack_state integer NOT NULL DEFAULT 0, furnace character varying(32) COLLATE pg_catalog."default", cooling_cover character varying(32) COLLATE pg_catalog."default", heating integer, base character varying(32) COLLATE pg_catalog."default", CONSTRAINT alarm_history_pk PRIMARY KEY (alarm_history_pkey), CONSTRAINT alarm_history_base_fk FOREIGN KEY (area, base) REFERENCES public.bases (area, base) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION, CONSTRAINT alarm_history_charge_fk FOREIGN KEY (charge) REFERENCES public.charges (charge) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION, CONSTRAINT alarm_history_cooler_fk FOREIGN KEY (cooling_cover, area) REFERENCES public.cooling_covers (cover, area) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION, CONSTRAINT alarm_history_device_fk FOREIGN KEY (device) REFERENCES public.bases (alarm_device) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION, CONSTRAINT alarm_history_furnace_fk FOREIGN KEY (furnace, area) REFERENCES public.furnaces (furnace, area) MATCH SIMPLE ON UPDATE NO ACTION ON DELETE NO ACTION)WITH ( OIDS = FALSE)TABLESPACE pg_default; ALTER TABLE public.alarm_history OWNER to caps;