extracting location info from string

A column contains location information, which may contain any of the
following:

1) null
2) country name (e.g. "France")
3) city name, region name (e.g. "Bonn, Nordrhein-Westfalen")
4) city name, Rg. region name (e.g. "Frankfurt, Rg. Hessen")
5) city name, Rg region name (e.g. "Frankfurt, Rg Hessen")

Using the tables below, I would like to derive COUNTRY.ID, REGION.CODE,
city name.




=====
CREATE TABLE person
( id integer NOT NULL, "name" character varying(256) NOT NULL, "location" character varying(256), CONSTRAINT
person_pkeyPRIMARY KEY (id)
 
);

CREATE TABLE country
( id character varying(3) NOT NULL, -- alpha-3 code "name" character varying(50) NOT NULL, CONSTRAINT country_pkey
PRIMARYKEY (id)
 
);

CREATE TABLE region
( country character varying(3) NOT NULL, code character varying(3) NOT NULL,"name" character varying(50) NOT NULL,
CONSTRAINTregion_pkey PRIMARY KEY (country, code), CONSTRAINT country_region_fk FOREIGN KEY (country)     REFERENCES
country(id) MATCH SIMPLE     ON UPDATE CASCADE ON DELETE RESTRICT
 
)


=====
System: PostgreSQL 8.4


-- 

Best Regards,
Tarlika Elisabeth Schmitz