oracle触发器

create or replace trigger InsertAISyn 
after update ON REQ_PROC
   FOR EACH ROW
DECLARE
OLDSTATUS VARCHAR2(64);
NEWSTATUS VARCHAR2(64);
STUDYUID  VARCHAR2(64);
STUDYID  VARCHAR2(64);
PATIENTID  VARCHAR2(64);
Modality  VARCHAR2(64);
StudyDesc  VARCHAR2(64);
BEGIN
NEWSTATUS :=:new.STATUS;
OLDSTATUS := :old.STATUS;
STUDYUID:=:new.STUDY_INS_UID;
Modality:=:new.MODALITY;
STUDYID:=:new.REQ_PROC_ID;
StudyDesc:=:new.PARTOFCHECK;










IF NEWSTATUS ='已检查' AND OLDSTATUS<>NEWSTATUS then
BEGIN
     delete hhpacs.SynAIStaus where STUDYUID= STUDYUID;
if(Modality = 'CT') then
   BEGIN
    insert into hhpacs.SynAIStaus(STUDYUID,STUDYID,PATIENTID,Modality,StudyDesc,SynStatus)
values(STUDYUID,STUDYID,PATIENTID,Modality,StudyDesc,0);
   END;
    end if;
END;
end if;
END;