drop sequence classroom_seqzhang;drop sequence course_seqzhang;drop sequence user_seqzhang;drop sequence student_seqzhang;drop sequence deploy_tbzhang;drop sequence sc_tbzhang;drop table classroom_tbzhang;drop table course_tbzhang;drop table user_tbzhang;drop table student_tbzhang;drop table deploy_tbzhang;drop table sc_tbzhang;create sequence classroom_seqzhang start with 1 increment by 1;create sequence user_seqzhang start with 1 increment by 1;create sequence course_seqzhang start with 1 increment by 1;create sequence student_seqzhang start with 1 increment by 1;create sequence deploy_seqzhang start with 1 increment by 1;create sequence sc_seqzhang start with 1 increment by 1;create table user_tbzhang(	id number(10) primary key,	username varchar2(20),	password varchar2(20),	permission number(10));insert into user_tbzhang values(1, 'administrator', 'administrator', 2);insert into user_tbzhang values(2, '11', '11', 1);create table classroom_tbzhang(	id number(10) primary key,	name varchar2(20));insert into classroom_tbzhang values(1, '1001');insert into classroom_tbzhang values(2, '1002');insert into classroom_tbzhang values(3, '1003');insert into classroom_tbzhang values(4, '1004');insert into classroom_tbzhang values(5, '1005');insert into classroom_tbzhang values(6, '1006');insert into classroom_tbzhang values(7, '1007');insert into classroom_tbzhang values(8, '1008');insert into classroom_tbzhang values(9, '1009');insert into classroom_tbzhang values(10, '2001');insert into classroom_tbzhang values(11, '2002');insert into classroom_tbzhang values(12, '2003');insert into classroom_tbzhang values(13, '2004');insert into classroom_tbzhang values(14, '2005');insert into classroom_tbzhang values(15, '2006');insert into classroom_tbzhang values(16, '2007');insert into classroom_tbzhang values(17, '2008');insert into classroom_tbzhang values(18, '2009');insert into classroom_tbzhang values(19, '3001');insert into classroom_tbzhang values(20, '3002');insert into classroom_tbzhang values(21, '3003');insert into classroom_tbzhang values(22, '3004');insert into classroom_tbzhang values(23, '3005');insert into classroom_tbzhang values(24, '3006');insert into classroom_tbzhang values(25, '3007');insert into classroom_tbzhang values(26, '3008');insert into classroom_tbzhang values(27, '3009');create table course_tbzhang(	id number(10) primary key,	name varchar2(50),	point number(5),	description varchar2(100));insert into course_tbzhang values(1, '高等數學', 6, '基礎課程');insert into course_tbzhang values(2, '數據結構', 6, '具有一定的語言基礎');insert into course_tbzhang values(3, 'c語言', 4, '對計算機有一個基本認識');insert into course_tbzhang values(4, '計算機文化基礎', 4, '基礎課程');insert into course_tbzhang values(5, '線性代數', 4, '具有一定的數學基礎');insert into course_tbzhang values(6, '網絡技術', 4, '對計算機有一個基本認識');insert into course_tbzhang values(7, '接口技術', 4, '對計算機有一個基本認識');insert into course_tbzhang values(8, '數據邏輯', 4, '對計算機有一個基本認識');insert into course_tbzhang values(9, '匯編語言', 4, '具有一定的計算機基礎');insert into course_tbzhang values(10, '操作系統', 4, '基礎課程');insert into course_tbzhang values(11, 'c++語言程序設計', 4, '具有c語言基礎');insert into course_tbzhang values(12, 'java語言程序設計', 4, '具有c語言基礎');insert into course_tbzhang values(13, '離散數學', 4, '基礎課程');insert into course_tbzhang values(14, '概率論', 4, '具有一定的數學基礎');insert into course_tbzhang values(15, '編譯原理', 4, '具備操作系統和算法');insert into course_tbzhang values(16, '圖形學', 3, '具有一定的數學基礎');insert into course_tbzhang values(17, '算法設計', 6, '會數據結構');insert into course_tbzhang values(18, 'vb程序設計', 2, '具有一定的程序基礎');insert into course_tbzhang values(19, 'vc程序設計', 2, '具有一定的程序基礎');insert into course_tbzhang values(20, 'web開發（asp）', 2, '上成課程');insert into course_tbzhang values(21, 'web開發（jsp）', 2, '上成課程');insert into course_tbzhang values(22, '網頁制作', 2, '基礎課程');insert into course_tbzhang values(23, '單片機', 2, '上成課程');insert into course_tbzhang values(24, '人工智能', 2, '上成課程');insert into course_tbzhang values(25, '電子技術', 4, '具有一定的數學基礎');insert into course_tbzhang values(26, '圖像編碼', 2, '上成課程');insert into course_tbzhang values(27, '網絡編程', 4, '上成課程');create table student_tbzhang(	id number(10) primary key,	name varchar2(50),	isselect int, 	grade varchar2(20),	institution varchar2(50));create table deploy_tbzhang(	id number(10) primary key,	time varchar2(60), 	course number(10),	roomid number(10),	num int);create table sc_tbzhang(	id number(10) primary key, 	studentid number(10), 	courseid number(10));