学生表一张,列为学生代码,学生名,对应教师代码教师表一张,列为 教师代码,教师名,对应课程代码课程表一张,列为课程代码,对应课程名教室表一张,列为 教室代码,课程代码,接入点create table students(sid number primary key not null,sname varchar2(30) not null,tid number not null);create table teachers(tid number primary key not null,tname varchar2(30) not null,lid number not null);create table lessons(...