create table vir_test 
( party_key varchar2(100),
  employee_key VARCHAR2(150 BYTE) GENERATED ALWAYS AS (w2_derived_value('E',party_key)) VIRTUAL VISIBLE
)

Error starting at line 1 in command:
create table vir_test 
( party_key varchar2(100),
  employee_key VARCHAR2(150 BYTE) GENERATED ALWAYS AS (w2_derived_value('E',party_key)) VIRTUAL VISIBLE
)
Error at Command Line:3 Column:56
Error report:
SQL Error: ORA-30553: The function is not deterministic
30553. 00000 -  "The function is not deterministic" 
*Cause:    The function on which the index is defined is not deterministic
*Action:   If the function is deterministic, mark it DETERMINISTIC.  If it
           is not deterministic (it depends on package state, database state,
           current time, or anything other than the function inputs) then
           do not create the index.  The values returned by a deterministic
           function should not change even when the function is rewritten or
           recompiled.

create or replace 
function w2_derived_value (v_exec_flg varchar2, v_exec_value varchar2)
        return varchar2
    AS
    
    v_ret_value varchar2(100);
    
  Begin
  
     if ( v_exec_flg = 'E' ) then
     
        Begin
        
            select rm into v_ret_value from ss_repo.party_info where party_key = trim(v_exec_value) ;
        
        Exception when no_data_found then
        
        v_ret_value := null;
        return v_ret_value;
        
        End;
        
        Return v_ret_value;
     
     End if;
  
  End w2_derived_value;

create or replace 
function w2_derived_value (v_exec_flg varchar2, v_exec_value varchar2)
        return varchar2 DETERMINISTIC
    iS
    
    v_ret_value varchar2(100);
    
  Begin
  
     if ( v_exec_flg = 'E' ) then
     
        Begin
        
            select rm into v_ret_value from ss_repo.party_info where party_key = trim(v_exec_value) ;
        
        Exception when no_data_found then
        
        v_ret_value := null;
        return v_ret_value;
        
        End;
        
        Return v_ret_value;
     
     End if;
  
  End w2_derived_value;

create table vir_test 
( party_key varchar2(100),
  employee_key VARCHAR2(4000 BYTE) GENERATED ALWAYS AS (ss_repo.w2_derived_value('E',party_key)) VIRTUAL VISIBLE
)