出现原因，是因为在更新的的表和读取的表是同一个表。

CREATE or replace TRIGGER T_userupdateT BEFORE update ON T_user REFERENCING OLD AS old NEW AS N_ROW FOR EACH ROW
DECLARE U_xtfidemp1 varchar(36);
u_xtempcode1 varchar(20);
u_xtempcodeCount int:=0;
U_xtfidempCount int:=0;
u_id1 int:=0;
BEGIN
U_xtfidemp1:=:N_ROW.U_xtfidemp;
u_xtempcode1:=:N_ROW.u_xtempcode;
u_id1:=:N_ROW.u_id;
select count(u_xtempcode) into u_xtempcodeCount from eas.T_user where u_xtempcode is not null and u_xtempcode=u_xtempcode1 and u_id<>u_id1;
select coun..