-- Cannot alter type of a column used in a trigger definition
DROP TRIGGER waterway_axis_wtwaxs_unique ON waterway.waterway_axis;

ALTER TABLE waterway.waterway_axis
    ALTER wtwaxs TYPE geography(MULTILINESTRING, 4326)
        USING ST_Multi(CAST(wtwaxs AS geometry));

-- Re-create trigger
CREATE CONSTRAINT TRIGGER waterway_axis_wtwaxs_unique
    AFTER INSERT OR UPDATE OF wtwaxs ON waterway.waterway_axis
    FOR EACH ROW EXECUTE FUNCTION prevent_st_equals('wtwaxs');