postgresql sql批量更新记录

CREATE FUNCTION updateTchrNm() RETURNS void AS
$body$
DECLARE
rownum integer := 1;
BEGIN
while rownum = 1000 LOOP
    update t_tchr set tchr_nm = '田中愛子' || rownum, tchr_knm = 'タナカアイコ' || rownum, tchr_anm = 'tanaka' || rownum where tchr_cd = 'TCHR' || (1000000 + rownum);
    rownum := rownum + 1;
END LOOP;
return;
END;

$body$ LANGUAGE 'plpgsql';
select updateTchrNm();