create table passenger(pnr number(10) primary key,
trainnumber number(5) foreign key references train(trainnumber),
noofseats number(4),
price number(4),
doj varchar2(10))

ORA-00907：缺少右括号

最佳答案 外键表达式是冗余的(读取：错误).语法只是添加引用：

create table passenger(pnr number(10) primary key,
trainnumber number(5) references train(trainnumber), -- here
noofseats number(4),
price number(4),
doj varchar2(10))