oracle数据库查询的含义是什么：主键引用t_name（col_name）？

create table books
( 
    bid   number(5)  primary key,
    name  varchar2(30)
);

create table members
( 
    mid    number(5)  primary key,
    name   varchar2(30)
);

create table issues
( 
    bid    number(5)  primary key
           references books(bid),
    mid    number(5)
           references members (mid)
);
create table books
( 
    bid   number(5)  prim