Create table student02(sno number);

Drop table student02;

Rename student02 to student01;

Alter table student01

--列的修改

Add ob number

Modify ob varchar2(2)

Rename column ob to obnew

Drop column obnew

--约束

Add constraint pk_student01 primary key(sno)

Add constraint uk_student01 unique (sname)

Add constraint fk_student01 foreign key(sno) references student(sno)

Add constraint ck_sno check(sno > 100)

Modify sno not null

Drop constraint fk_student01

Modify sno null;

Create index ix_student01 on student01(sname);

Drop index ix_student01;

Create synonym stu01 for student01;

Drop synonym stu01;