Not Null problems

[sambavan]

 SELECT table_name,column_name
    FROM user_tab_columns 
  WHERE nullable = 'N';

You can either spool them and modify them and run that script once or, you can create the script on the fly using the above statements and then edit them and then run

  eg: 
        SPOOL alter_table_column.sql

        SELECT 'ALTER TABLE '||table_name||'MODIFY ('||column_name||' NULL); '
         FROM user_tab_columns
        WHERE nullable = 'N';

        SPOOL OFF;

Remeber to edit the above script to remove those which has the key constraints enforced.

Sam