企业网站开发报价形式,百度sem是什么意思,做微商自己建网站合适吗,西安风险等级最新目录
1.建立数据表并插入数据
2 视图的创建
2.1 行列子集视图的创建
2.2 多表视图
2.3视图上建立视图
2.4分组视图
2.5带表达式的视图
3 删除视图
4 查询视图
5 更新视图
5.1 修改某一个属性
5.2 删除一条数据
5.3 插入…目录
1.建立数据表并插入数据
2 视图的创建
2.1 行列子集视图的创建
2.2 多表视图
2.3视图上建立视图
2.4分组视图
2.5带表达式的视图
3 删除视图
4 查询视图
5 更新视图
5.1 修改某一个属性
5.2 删除一条数据
5.3 插入一条数据
6 索引
6.1建立索引
6.2修改索引
6.3删除索引 1.建立数据表并插入数据
SQL语句
create database ExperimentFour;use ExperimentFour;create table Student4( Sno char(2) not null, Sname varchar(20) not null, Ssex char(2) not null, constraint s2 check(Ssex in(男, 女)), Sage int not null, constraint s3 check (Sage between 0 and 130), Department varchar(20) not null);create table Course4( Cno char(2) not null , Cname varchar(20) not null, Cprepare varchar(20) not null, Ccredit float not null, constraint c3 check(0 Ccredit));create table SC4( Sno char(2) not null, Cno char(2) not null, Performance float not null, constraint sc1 check(Performance between 0 and 100));insert into student4(sno, sname, ssex, sage, department)values (21, 张三, 男, 18, 计通学院), (04, 李四, 男, 19, 化学院), (02, 翠花, 女, 18, 文新学院);insert into course4(cno, cname, cprepare, ccredit)values (11, 概率论, 高等数学, 3), (12, 数字电路, 离散结构, 2.5), (13, 数据结构, 离散结构, 3.5), (01, 嵌入式, 数字电路, 2);insert into sc4(sno, cno, performance)values (21, 11, 66), (02, 01, 89), (04, 12, 59);
截图 2 视图的创建
2.1 行列子集视图的创建
SQL语句
use experimentfour;create view ComputerStudentasselect Sname, Sno, Sagefrom student4where Department 计通学院with check option;select *from ComputerStudent;
截图 2.2 多表视图
SQL语句
use experimentfour;create view Chinese_S1(Sno, Sname, Performance)asselect student4.Sno, Sname, Performancefrom student4, sc4where Department 文新学院 and student4.Sno sc4.Sno and sc4.Cno 1;select *from Chinese_S1;
截图 2.3视图上建立视图
SQL语句
use experimentfour;create view GoodStudent(Sno, Sname)asselect Sno, Snamefrom chinese_s1where Performance 80;select *from GoodStudent;
截图 2.4分组视图
SQL语句
use experimentfour;create view S_G(Sno, Performance)asselect Sno, AVG(Performance)from sc4group by Sno;select *from S_G;
截图 2.5带表达式的视图
SQL语句
use experimentfour;create view BT_S(Sno, Sname, Birth)asselect Sno, Sname, 2023 - Sagefrom student4;select *from BT_S;
截图 3 删除视图
SQL语句
use experimentfour;drop view goodstudent;
截图 4 查询视图
SQL语句
use experimentfour;select Sno, Performancefrom s_gwhere Performance 60;
截图 5 更新视图
5.1 修改某一个属性
SQL语句
use experimentfour;update computerstudentset Sname 沸羊羊where Sno 21;select *from computerstudent;
截图 5.2 删除一条数据
SQL语句
use experimentfour;deletefrom computerstudentwhere Sno 21;select *from computerstudent;
截图 5.3 插入一条数据
SQL语句
use experimentfour;create view studentasselect * from student4;insert into studentvalues (10, 李明, 男, 20, 能动学院);select * from student;
截图 6 索引
6.1建立索引
SQL语句
use experimentfour;create unique index Stusno on Student4(Sno);create unique index Coucno on Course4(Cno);create unique index SCno on SC4(Sno ASC, Cno DESC);
6.2修改索引
SQL语句
use experimentfour;alter table sc4 rename index SCno to SCSno;
6.3删除索引
SQL语句
use experimentfour;drop index Stusno on student4;
