SQL Snippets ™: Tutorials for Oracle Developers

create table t
(
  key  number       primary key
, val  varchar2(5)
) ;

insert into t values ( 1, 'a'  );
insert into t values ( 2, 'b'  );
insert into t values ( 3, 'c'  );
insert into t values ( 4, null );

commit;

create table t_backup as
  select * from t
;

create table t2
(
  key    number  primary key
, t_key  number  not null references t
, amt    number  not null
) ;

insert into t2 values ( 10, 1, 100 ) ;
insert into t2 values ( 20, 1, 300 ) ;
insert into t2 values ( 30, 1, 200 ) ;
insert into t2 values ( 40, 2, 250 ) ;
insert into t2 values ( 50, 2, 150 ) ;
commit;

create table t2_backup as
  select * from t2
;