NOT null constraint in SQL loader URGENT

[jothish chokkalingam]

hi all
I facing an issue in SQL loader i.e
my input data file is
name id age
------------------
P12
P 3
z89
it is a tab delimited file.
my table will be
CREATE TABLE data1(NAME VARCHAR2(10),id VARCHAR2(10),age NUMBER(3))
i want to include a constraint in ctrl file as
if in the input data if NAME is 'P' then we can't insert null value for id field in the table data1
if the input data for NAME is not equal to 'P' then we can insert null value for id field in the table data1
my sample ctrl file is

   LOAD DATA
   INFILE 'D:\Phase1\in.csv'
   APPEND
   INTO TABLE 
     data1
   FIELDS TERMINATED BY X'09' TRAILING NULLCOLS 
      (
  NAME  char,
  CASE ID 
  WHEN  NAME='P'
  THEN '0'
  ELSE ID,
   AGE INTEGER EXTERNAL
    )  

How can we handle this kind of constraint in SQL loader?

It is urgent.
Kindly help me out.

[ September 13, 2006: Message edited by: jothish chokkalingam ]
[ September 13, 2006: Message edited by: jothish chokkalingam ]