PL SQL 中的 WHILE 循环有什么问题？

Question

我正在 PL/SQL 上练习集合，现在我编写了一个简单的 WHILE 循环，用于在屏幕上打印稀疏关联数组的值。我收到以下错误：Oracle 错误 -06502：PL/SQL：数字或值错误：NULL 索引 table 键值。结果打印在屏幕上，但也有 oracle 错误。谢谢

SET SERVEROUTPUT ON

DECLARE

  TYPE type_football_players IS TABLE OF VARCHAR2(45)
       INDEX BY PLS_INTEGER;

  v_costademarfil_2006 type_football_players;

  v_counter PLS_INTEGER;
BEGIN

  v_costademarfil_2006(9)  := 'Kone';
  v_costademarfil_2006(10) := 'Yapi Yapo';
  v_costademarfil_2006(11) := 'Drogba';
  v_costademarfil_2006(14) := 'Kone';
  v_costademarfil_2006(15) := 'Dindane';
  v_costademarfil_2006(19) := 'Toure';
  v_costademarfil_2006(21) := 'Eboue';

  v_counter := v_costademarfil_2006.FIRST;

  WHILE v_costademarfil_2006(v_counter) IS NOT NULL
  LOOP
        DBMS_OUTPUT.PUT_LINE(v_costademarfil_2006(v_counter));

        v_counter := v_costademarfil_2006.NEXT(v_counter);
  END LOOP;
END;

Informe de error - ORA-06502: PL/SQL: numeric or value error: NULL index table key value ORA-06512: at line 48 06502. 00000 - "PL/SQL: numeric or value error%s" *Cause: An arithmetic, numeric, string, conversion, or constraint error occurred. For example, this error occurs if an attempt is made to assign the value NULL to a variable declared NOT NULL, or if an attempt is made to assign an integer larger than 99 to a variable declared NUMBER(2). *Action: Change the data, how it is manipulated, or how it is declared so that values do not violate constraints.

Kone Yapi Yapo Drogba Kone Dindane Toure Eboue

Answer 1

您的 WHILE 循环条件不正确。

您需要检查 v_counter 是否为 NULL，而不是 v_costademarfil_2006(v_counter) 是否为 NULL。

循环的最后一次，v_counter 为 NULL，因此计算 v_costademarfil_2006( NULL )。这导致打印所有名称后出现错误。

PL SQL 中的 WHILE 循环有什么问题？

What is wrong with the WHILE Loop on PLSQL?

oracle

plsql

while-loop

sparse-matrix