Cascade Delete is not work - postgresql

Question

I am not able to delete record from parent table of PostGres DB.. Any one of you can get me an idea on this.
-- Table: tbl_patient
-- DROP TABLE tbl_patient;
CREATE TABLE tbl_patient
(
patient_id bigserial NOT NULL,
date_of_birth date NOT NULL,
fathers_name character varying(255) NOT NULL,
first_name character varying(255) NOT NULL,
last_name character varying(255),
marital_status character varying(255),
mobile_number character varying(255) NOT NULL,
occupation character varying(255),
phone_number character varying(255),
pregnancy_status character varying(255),
sex character varying(255) NOT NULL,
CONSTRAINT tbl_patient_pkey PRIMARY KEY (patient_id)
)
WITH (
OIDS=FALSE
);
ALTER TABLE tbl_patient
OWNER TO postgres;
-- Table: tbl_address
CREATE TABLE tbl_address
(
address_id bigserial NOT NULL,
address_line_1 character varying(255) NOT NULL,
address_line_2 character varying(255),
city character varying(255),
country character varying(255),
district character varying(255) NOT NULL,
pincode character varying(255) NOT NULL,
state character varying(255),
street character varying(255),
patient_id bigint,
CONSTRAINT tbl_address_pkey PRIMARY KEY (address_id),
CONSTRAINT fk_slc6pgeimmox5buka8bydy6c4 FOREIGN KEY (patient_id)
REFERENCES tbl_patient (patient_id) MATCH SIMPLE
ON UPDATE NO ACTION ON DELETE NO ACTION
)
WITH (
OIDS=FALSE
);
ALTER TABLE tbl_address
OWNER TO postgres;
//-------------------------------------------------------------------
When I put this command
DELETE FROM tbl_patient
WHERE patient_id = 1;
I got this error below
ERROR: update or delete on table "tbl_patient" violates foreign key
constraint "fk_slc6pgeimmox5buka8bydy6c4" on table "tbl_address" SQL
state: 23503 Detail: Key (patient_id)=(1) is still referenced from
table "tbl_address".

Answer 1

You write DELETE NO ACTION and you wanting actions:) Just need to change to
REFERENCES tbl_patient (patient_id) MATCH SIMPLE
ON UPDATE NO ACTION ON DELETE CASCADE
NO ACTION means that server wont do anything with referenced rows if they exists. Since they exists and you specified also MATCH SIMPLE to one-column-foreign key then PostgreSQL cannot perform deletion because of that referenced rows.