CREATE TABLE ADDRESSES
(
address_id  NUMBER
        CONSTRAINT addresses_address_id_pk PRIMARY KEY,
city        VARCHAR2 (100)
        CONSTRAINT addresses_city_nn NOT NULL,
postcode    VARCHAR2 (9)
        CONSTRAINT addresses_postcode_nn NOT NULL,
geometry    MDSYS.SDO_GEOMETRY
        CONSTRAINT addresses_geometry_nn NOT NULL
);

CREATE SEQUENCE seq_addresses_address_id
START WITH 1
INCREMENT BY 1
NOCACHE;

CREATE OR REPLACE TRIGGER trg_addresses_address_id
BEFORE INSERT ON addresses FOR EACH ROW
BEGIN
    :NEW.address_id := seq_addresses_address_id.NEXTVAL;
END;