求数据库这句代码怎么用语言来表达?

用数据结构组织起来就是简单的数据库了，无非就是插入删除修改之类的功能

你说的那些数据库语句，可以用简单的字符串匹配来做

如：

strcmp

匹配"create

table"这个字符串

对接下来字符进行提取，直到"("

以后的关键字符也是用类似方法判断","等实现

提取了需要的关键字符之后就可以进行对应的传参，调用相应 *** 作

1、select Cno,Cname from Course where Teacher='刘老师'

2、select Sno,Sname from Student where Sage <22

3、select Sname from Student where Sno not in(

select Sno from sc inner join Course on sc.Cno=Course.Cno where Course.Teacher='刘老师')

4、select Sname from Student where Sno in(

select Sno from sc inner join Course on sc.Cno=Course.Cno where sc.Grade>90 and Course.Cname='程序设计')

5、select Sname from Student where Sno not in(

select Sno from sc inner join Course on sc.Cno=Course.Cno where Course.Cname='C3课')

6、select Sno from Student where Sno not in(

select Sno from sc inner join Course on sc.Cno=Course.Cno where Course.Cname='C1课' or Course.Cname='C2课')

group by Sno having count(*) >= 2

---

以上，希望对你有所帮助。

---