Error: PLS-00201: 必须声明标识符 'EVEN'

1、错误描述

Compilation errors for FUNCTION SCOTT.ODD

Error: PLS-00201: 必须声明标识符 ‘EVEN‘
Line: 4
Text: Result := not Even(Value);

Error: PL/SQL: Statement ignored
Line: 4
Text: Result := not Even(Value);

create or replace function Odd(Value in integer) return boolean is 
    Result boolean;
   begin 
    Result := not Even(Value);
    return (Result);
   end Odd; 

3、解决办法

create or replace function Even(Value in integer) return boolean is
    Result boolean;
   begin
     Result := (Value mod 2 = 0);
     return (Result);
   end Even;

Error: PLS-00201: 必须声明标识符 'EVEN'

原文：http://blog.csdn.net/you23hai45/article/details/50302215