设置外键的命令

create table dept(
   dep_id int primary key,
   dep_name nvarchar(20) not null,
    dep_address nvarchar(50)
)
create table emp(
   emp_id int constraint pk_empl_id_first primary key,
   emp_name nvarchar(20) not null,
   emp_*** nchar(2),
   dep_id int constraint fk_dep_id_second foreign key references dep(dep_id)
)