Oracle join on 2 int fields vs. char or float field

Does anyone know whether it is faster to left join on two integer fields or one text field or one float field? CHAR select t1.f1, t2.f1 ... from t1, t2 where t1.char_field_1 = t2.char_field_1(+) and .... The char field would be something like 12345-9876543 OR FLOAT select t1.f1, t2.f1 ... from t1, t2 where t1.float_field_1 = t2.float_field_1(+) and .... The float field would be something like 12345.9876543 OR 2 INTEGERS select t1.f1, t2.f1 ... from t1, t2 where t1.int_field_1 = t2.int_field_1(+) and t1.int_field_2 = t2.int_field_2(+) and .... The integer fields would be 12345 and 9876543 Thanks, Dan