JAVA高级面试进阶训练营视频教程

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例子如下

set serveroutput on;

declare
   V_SQL VARCHAR2(255);
   errorCode number; --异常编码  
   errorMsg varchar2(1000); --异常信息
   out_return varchar2(1000);
    flag varchar2(10);
CURSOR TP IS
  SELECT TABLE_NAME,CONSTRAINT_NAME FROM USER_CONSTRAINTS  WHERE CONSTRAINT_TYPE = 'P';
begin
    FOR E IN TP LOOP
    BEGIN
    V_SQL := 'ALTER TABLE ' || E.TABLE_NAME || ' ' || 'DISABLE' ||'  '|| 'CONSTRAINT ' || E.CONSTRAINT_NAME;
    DBMS_OUTPUT.PUT_LINE(V_SQL);
    EXECUTE IMMEDIATE (V_SQL);
     EXCEPTION
     when others then
         errorCode := SQLCODE;    
          errorMsg := SUBSTR(SQLERRM, 1, 200);   
              flag := 'false';  
        out_return := 'flag=' || flag || ',errorCode=' || errorCode || ',errorMsg=' || errorMsg;
        dbms_output.put_line(out_return);
      null;
    END;
   END LOOP;
end;

 

注意问题

1、捕捉异常后继续下一次循环需用

     EXCEPTION
     when others then  null;

    这样的结构。

2、在for ...LOOP   ENDLOOP 循环中捕捉异常，必须用begin   end 包起来，否则会报错。在PLSQL中报

    PLS-00103: Encountered the symbol "EXCEPTION" when expecting one of the following
    Error: PLS-00103: Encountered the symbol "END" when expecting one of the following

  正确

    FOR E IN TP LOOP
    begin
      ......................
     EXCEPTION
     when others then  null;

   end;

   endloop;

 

错误用法：

FOR E IN TP LOOP
      ......................
     EXCEPTION
     when others then  null;

   endloop;