How to load the file dynamic file structure, but in my scenario structure(Metadata) changing frequently

Hi Experts,

How to load the file dynamic file , but in my scenario structure(Metadata) changing  file to file.

For Example :

FILE-1 :

EMP_ID     EMP_NAME     SAL

FILE-2 :

EMP_ID     EMP_NAME     SAL     ADDRESS

in this scenario how load the data into respective target table.

Thanks in Advance.