select b.table_name Child_table,a.table_name parent_table ,b.constraint_name,b.r_constraint_name
from user_constraints b,user_constraints a
where a.constraint_type='P' And
a.constraint_name=b.r_constraint_name
order by b.table_name;

Try this query. It will give the child table_name,parent table_name,constraint_name,r_constraint_name. It will give order by Child table.