ddl - How to add a new column with foreign key constraint in a single statement in oracle -

how add new column foreign key constraint in single statement in oracle.can 1 give example query.

alter table tab1 add c1 number(20) constraint tab1_c1_fk references tab2(c2) ; 

c1 - new column in table tab1 fk tab1_c1_fk on table tab2 column c2