对自定义函数建立索引时抛异常--ORA-30553: 函数不能确定（ORA-30553: The function is not deterministic）解决方法

 对自定义函数建立索引时抛异常--ORA-30553: 函数不能确定（ORA-30553: The function is not deterministic）解决方法
问题描述：
SQL> create or replace function f_16turnto10(
  2    str_16char  in varchar2
  3  )return integer
  4  is
  5    i_number number(10);
  6   i_int  int;
  7  begin
  8    i_int := length(str_16char)+10;
  9    i_number := to_number(str_16char,rpad('x',i_int,'x'));
 10   return i_number;
 11  end;
 12  /
 
Function created
 
SQL> create table t_16turn10 as select username,'4D' as psw  from dba_users;
 
Table created
 
SQL> create index i_16turn10 on t_16turn10 (f_16turnto10(psw));
 
create index i_16turn10 on t_16turn10 (f_16turnto10(psw))
 
ORA-30553: 函数不能确定
解决如下：
如果需要创建基于自定义函数的索引,那么我们需要指定deterministic参数，在函数建立的时候指定该参数问题可解决。
SQL> create or replace function f_16turnto10(
  2    str_16char  in varchar2
  3  )return integer deterministic
  4  is
  5    i_number number(10);
  6   i_int  int;
  7  begin
  8    i_int := length(str_16char)+10;
  9    i_number := to_number(str_16char,rpad('x',i_int,'x'));
 10   return i_number;
 11  end;
 12  /
Function created

SQL> create table t_16turn10 as select username,'4D' as psw  from dba_users;
 
Table created
 
SQL> create index i_16turn10 on t_16turn10 (f_16turnto10(psw));
 
Index created