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 count(U_xtfidemp) into U_xtfidempCount from eas.T_user where U_xtfidemp is not null and U_xtfidemp=U_xtfidemp1 and u_id<>u_id1; IF u_xtempcodeCount>0 or U_xtfidempCount>0 THEN RAISE_APPLICATION_ERROR(-20001, 'eas.T_user u_xtempcode,U_xtfidemp,U_GZCode更新数据时有错误,有重复'); END IF; end;

出现错误时，是因为触发器在T_userupdateT在T_user上，触发器内部有读取了T_user所以有错误。

修改如下

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; PRAGMA AUTONOMOUS_TRANSACTION;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 count(U_xtfidemp) into U_xtfidempCount from eas.T_user where U_xtfidemp is not null and U_xtfidemp=U_xtfidemp1 and u_id<>u_id1; IF u_xtempcodeCount>0 or U_xtfidempCount>0 THEN RAISE_APPLICATION_ERROR(-20001, 'eas.T_user u_xtempcode,U_xtfidemp,U_GZCode更新数据时有错误,有重复'); END IF;COMMIT; end;

多了PRAGMA AUTONOMOUS_TRANSACTION;COMMIT;两句

以上这篇Oracle触发器表发生了变化 触发器不能读它的解决方法(必看)就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。