create table firstnames (
 id integer primary key not null,
 firstname varchar(250),
 lastname_id integer
);

create table lastnames (
 id integer primary key not null,
 lastname varchar(250)
);

insert into firstnames (id,firstname,lastname_id) values (1,'Sam',1);
insert into firstnames (id,firstname,lastname_id) values (2,'Mike',2);
insert into firstnames (id,firstname,lastname_id) values (3,'John',0);
insert into firstnames (id,firstname,lastname_id) values (4,'Dan',null);

insert into lastnames (id,lastname) values (1,'Johnson');
-- insert into lastnames (id,lastname) values (2,'Peterson');
