ora-06502

今天使用到动态的sql：
用的方法是：
用if else 拼出sql文，然后用
“open cursor for sql”来执行。
-- 大概代码如下
create or replace....
is
    var_sql    varchar2(4000);
    TYPE typCur IS REF CURSOR;
    cur typCur;
    rec aType.aRecord%type;       -- aRecord是一个record
begin
    var_sql := '';
    if...then
        var_sql :=var_sql|| 'select a, b, c'..||..||..;
    elsif... then
        var_sql :=var_sql||..||..||..;
    end if;
   
    if...then
        var_sql := var_sql||'..';
    end if;
   
    open cur for var_sql
        loop fetch cur into rec
        exit when cur%notfound;
        ...
    end loop;
    close cur;
exception
    when others then
        close cur;
end;
/*
* 1. 由于拼的东西sql文太长，当我将拼好的var_sql塞给var_sql时，会报06502的错，如果定义时将var_sql定义为varchar2(32000)
*     【oracle db里面varchar2最长为4000bytes，而plsql在处理时，能处理的最长的是32000bytes】
*2. 1的问题完了之后，程序能执行到“fetch cur into rec”，rec在定义的时候定义的type与select检索到的不一致，比如是b,a,c
*/




ORA-06502 PL/SQL: numeric or value error string

    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.