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在表中找不到给定记录时,如何处理游标中的异常

oracle10g plsql oracle

P Prad · 技术社区 · 7 年前

我正在更新 emp3 (与emp表相同)使用游标进行循环,

DECLARE 
   CURSOR incr_cur IS SELECT * FROM emp3 FOR UPDATE OF sal;
   v_job emp3.job%TYPE := '&ENTER_Job';
   v_cnt INTEGER := 0;
BEGIN
  FOR r_l IN incr_cur LOOP
    IF v_job IN (r_l.job) THEN
      UPDATE emp3 SET sal = sal + 100 WHERE CURRENT OF incr_cur;
    END IF;
 END LOOP;

 FOR r_l IN incr_cur LOOP
    IF v_job IN (r_l.job) THEN
      v_cnt := v_cnt + 1;
      DBMS_OUTPUT.PUT_LINE('The Salary of ' || r_l.ename || ' is Incremented by 100 and the Updated Salary is: $' || r_l.sal);
    END IF;
 END LOOP;

     DBMS_OUTPUT.PUT_LINE('The Salary of '|| v_cnt ||' Employees are Updated');
END;

当执行PL/SQL块时,它将请求作业, 我给 MANAGER ,然后是 经理 增加100。这个 emp3 表有5个工作类别 CLERK ,则, 经理 ,则, ANALYST ,则, SALESMAN 和 PRESIDENT 。然后如何显示消息 作业未列出,因此无法更新。 ,如果用户输入的作业不在表中,例如 DEVELOPER 。我尝试了异常处理,但无法使其正常工作。

2 回复 | 直到 7 年前

William Robertson 7 年前

不需要单独的步骤。只需尝试更新,如果没有行被更新,请这样说。如果您希望它是一个例外,那么使用 raise_application_error 。

假设这是一个学习练习,这就是为什么你不想做一个普通的 update ,您可以这样做:

declare 
    k_job constant emp3.job%type := '&JOB';

    cursor employees_cur is
        select * from emp3
        where  job = k_job
        for update of sal;

    v_update_count integer := 0;
    v_payroll_increase integer := 0;
begin
    for r in employees_cur loop
        update emp3 set sal = sal + 100 where current of employees_cur;
        dbms_output.put_line('Salary for ' || r.ename || ' is incremented by $100 from $' || r.sal || ' to $' || (r.sal +100));
        v_update_count := v_update_count + 1;
        v_payroll_increase := v_payroll_increase + 100;
    end loop;

    if v_update_count = 0 then
        dbms_output.put_line('No staff are currently employed as ' || k_job ||'. Payroll is unchanged.');
    else
        dbms_output.put_line('Updated salary of '|| v_update_count ||' employee' || case when v_update_count <> 1 then 's' end||'.');
        dbms_output.put_line('Payroll increased by $'||v_payroll_increase||'.');
    end if;
end;
/

Enter value for job: SALESMAN
Salary for ALLEN is incremented by $100 from $1600 to $1700
Salary for WARD is incremented by $100 from $1250 to $1350
Salary for MARTIN is incremented by $100 from $1250 to $1350
Salary for TURNER is incremented by $100 from $1500 to $1600
Updated salary of 4 employees.
Payroll increased by $400.

PL/SQL procedure successfully completed.

对于一个不存在的工作,您可以得到:

Enter value for job: ASTRONAUT
No staff are currently employed as ASTRONAUT. Payroll is unchanged.

(在本例中, v_payroll_increase 总是100次 v_update_count ,但如果你想加薪10%或按部门等不同的幅度加薪,可能会更有用。)

Littlefoot 7 年前

这里有一个选项:检查这样的工作是否存在;否则,查询将返回 NO_DATA_FOUND 您可以使用适当的消息处理并引发异常。否则,请继续 UPDATE 。

SQL> declare
  2    l_job emp.job%type;
  3  begin
  4    begin
  5      select job
  6        into l_job
  7        from emp
  8        where job = '&ENTER_Job'
  9          and rownum = 1;
 10    exception
 11      when no_data_found then
 12        raise_application_error(-20000, 'That job does not exist');
 13    end;
 14
 15    -- Job exists, so - go on with the update
 16  end;
 17  /
Enter value for enter_job: MANAGER

PL/SQL procedure successfully completed.

SQL> /
Enter value for enter_job: DEVELOPER
declare
*
ERROR at line 1:
ORA-20000: That job does not exist
ORA-06512: at line 12


SQL>

P、我更喜欢通过存储过程(接受作业名称作为参数)而不是匿名PL/SQL块来完成这样的工作。