How to default the datatype size for column referring in sql loader control file based on table colu

Hi ,

I need to know is there any way to default the datatype size for the column referring in sql loader control file based on the table column..

Ex ,,

I'm using a TABLE XX with column AA varchar2(300),BB varcahr2(50)

in control file instead of mentioning the value like

AA   char(300)  ,

...

Because , whenever i change the size of column in DB , i need to change the value in control file which needs manual effort to overcome this..

Is there anyway to default the size based on DB ..

Pls share your suggestions ..

Thanks,

Pavan