SELECT fieldA, fieldB, fielbC
INTO temp_table
FROM dblink('dbname=dbname port=5432 host=a.b.c.d user=user password=pw',
E'SELECT fieldA, fieldB, fieldC FROM data_table')
AS temp_table(fieldA integer, fieldB integer, fieldC integer);

CREATE OR REPLACE FUNCTION archive() RETURNS trigger AS $$
DECLARE
BEGIN

    execute
    '
SELECT fieldA, fieldB, fielbC
INTO temp_table
FROM dblink(''dbname=dbname port=5432 host=a.b.c.d user=user password=pw'',
E''SELECT fieldA, fieldB, fieldC FROM data_table'')
AS temp_table(fieldA integer, fieldB integer, fieldC integer);
    ';

    return new;
END;
$$ LANGUAGE plpgsql;