为表t_teacher中的teacher_id设置为主键。
举一反三
- 删除表teacher(id,name,gender,birthday,score)中id为4的老师( ) A: delete from teacher; B: delete from teacher where id = 4; C: delete teacher where id = 4; D: drop from teacher where id = 4;
- 以下新建对象的语句中,正确的一项是( )。 A: Teacher t; B: Teacher t=new<br/>Teacher (); C: Teacher (t)=new<br/>Teacher (); D: Teacher (t);
- 智慧职教: 表结构如下：teacher(tid,tname),course(cid,cname,teacher_id),查询所有课程的名称及任课老师姓名。
- 查看teacher表的表结构，语句为（） A: select * from teacher; B: show create table teacher; C: show table teacher; D: desc teacher;
- 设有关系表：teacher(tid,tname,tsex,tbdate),完善以下语句，将teacher表的性别列tsex的值都设置为“女”。（请用小写字母英文符号答题） UPDATE teacher SET ________