Live ORACLE

DECLARE
TYPE population_type IS TABLE OF NUMBER INDEX BY VARCHAR2(64);
country_population population_type;
continent_population population_type;
howmany NUMBER;
which VARCHAR2(64);
BEGIN
country_population('Greenland') := 100000; -- Creates new entry
country_population('Iceland') := 750000; -- Creates new entry
-- Looks up value associated with a string
howmany := country_population('Greenland');
continent_population('Australia') := 30000000;
continent_population('Antarctica') := 1000; -- Creates new entry
continent_population('Antarctica') := 1001; -- Replaces previous value
-- Returns 'Antarctica' as that comes first alphabetically.
which := continent_population.FIRST;
-- Returns 'Australia' as that comes last alphabetically.
which := continent_population.LAST;
-- Returns the value corresponding to the last key, in this
-- case the population of Australia.
howmany := continent_population(continent_population.LAST);
END;
/

Declaring Collection Types