在SQL表创建期间是否还有其他方法可以创建约束？

drop table department cascade constraints;
drop table facultyStaff cascade constraints;
drop table student cascade constraints;
drop table campusClub cascade constraints;
drop table studentClub cascade constraints;

create table department 
(   code      varchar2(3) primary key,name      varchar2(40)  not null,chair     varchar2(11));

create table facultyStaff 
(   staffID     varchar2(5) primary key,dob     date,firstName   varchar2(20),lastName    varchar2(20),rank        varchar2(10),deptCode    varchar2(3),constraint rankValue check (rank in ('Assistant','Associate','Full','Emeritus')),constraint facultyDeptFk foreign key (deptCode) references department (code));

create table student 
(   studentId   varchar2(5) primary key,status      varchar(10),major       varchar(3),constraint statusValue check (status in ('Freshman','Sophomore','Junior','Senior','Graduate')),constraint studentMajorFk foreign key (major) references department (code));

alter table department 
    add constraint departmentChairFk foreign key(chair) references facultyStaff(staffId) on delete set null;

由于主席与教职员之间存在主席关系的递归参考,因此在定义教师表之前,无法定义部门主席的外键约束.在使用alter table语句定义faculty之后,必须添加约束.

有没有其他方法可以做到这一点,以某种方式自动化约束创建,从而消除alter table语句？

解决方法

create schema authorization [schema name]
create table department 
(   code      varchar2(3) primary key,chair     varchar2(11),constraint departmentChairFk foreign key(chair) references facultyStaff(staffId) on delete set null
)
create table facultyStaff 
(   staffID     varchar2(5) primary key,constraint facultyDeptFk foreign key (deptCode) references department (code)
)
create table student 
(   studentId   varchar2(5) primary key,constraint studentMajorFk foreign key (major) references department (code)
);

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