如何给Sqlite添加复合主键

sqlite> create table t2 (
   ...>         id1     int ,
   ...>         id2 int,
   ...>         col     varchar(20),
   ...>         constraint pk_t2 primary key (id1,id2)
   ...> );
sqlite>
如果是双主键如下：
sqlite> create table t1 (
   ...>         id      int primary key,
   ...>         col     varchar(20)
   ...> );
sqlite> create unique index uk_t1 on t1 (col);