zoukankan      html  css  js  c++  java
  • Oralce_DDL

    --创建表
    --使用create table语句建立学生信息表,该表共包括学号(id)、姓名(name)、年龄(age)、入学日期(sdate)、年级(grade)默认值为1、班号(class)、email等信息
    create table student (
    id number(6)  not null,
    name varchar2(20),
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6) ,
    email varchar2(50)
    )
    select * from student
    insert into student (id) values (10012)
    desc student
    --使用create table语句建立班级信息表,该表共包括班级号(id)、班名(name)等信息
    create table class(
    id number(6),
    name varchar2(50)
    )
    desc class
    --创建一张和emp一样表结构的表
    create table emp2 as select * from emp
    select * from emp2
    --创建一张包含雇员表中雇员名和部门表中部门名的表
    create table emp_dept as select ename,dname from emp inner join dept on emp.deptno=dept.deptno
    desc emp_dept
    select * from emp_dept


    drop table student
    desc student
    --创建表时指定约束条件
    --非空约束(字段级)  姓名不可以为空值
    create table student (
    id number(6),
    name varchar2(20) not null,
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6) ,
    email varchar2(50)
    )
    desc student
    insert into student (name,age)values ('AA',10)
    select * from student
    drop table student


    create table student (
    id number(6),
    name varchar2(20) constraint not_null_name not null,
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6) ,
    email varchar2(50)
    )
    --唯一性约束(字段级/表级)  email字段不可以重复
    drop table student

    create table student (
    id number(6),
    name varchar2(20),
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6) ,
    email varchar2(50)  unique
    )

    create table student1 (
    id number(6),
    name varchar2(20),
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6) ,
    email varchar2(50)  ,
    constraint unique_sdate_email unique(sdate,email)
    )

    insert into student (email)  values ('admin@163.com')
    insert into student (email)  values ('admin@163.com')
    --主键约束(表级)   学号为主键 表级 not null ,unique
    drop table student
    create table student2 (
    id number(6) primary key,
    name varchar2(20),
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6) ,
    email varchar2(50) 
    )

    insert into student2 (id,name) values (1,'AA')
    insert into student2 (id,name) values (1,'BB')
    create table student3 (
    id number(6) ,
    name varchar2(20),
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6) ,
    email varchar2(50)  ,
    constraint pk_student2 primary key (id)
    )

    --外键约束(字段级/表级)   班级的取值必须为class表中的id值
    create table class2 (
    id number(8) primary key,
    name varchar2(20)
    )
    create table student4 (
    id number(6) ,
    name varchar2(20),
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6) references class2(id),
    email varchar2(50)
    )
    insert into class2 (id,name) values (1,'class_one')
    insert into student4(class) values (1)
    delete from class2

    create table student5 (
    id number(6) ,
    name varchar2(20),
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6),
    email varchar2(50) ,
    constraint fk foreign key (class) references class2(id)
    )
    --检查约束(表级)  年龄不可以为负值
    create table student6 (
    id number(6) ,
    name varchar2(20),
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(6),
    email varchar2(50) ,
    constraint check_age check (age>0)
    )
    insert into student6 (age) values (37)
    select * from student6

    --查看约束
    select t1.constraint_name,t1.table_name,t1.column_name,t2.constraint_type
    from user_cons_columns t1
    inner join  user_constraints t2 on t1.constraint_name=t2.constraint_name
    and t1.table_name=t2.table_name
    where t1.table_name='STUDENT'

    select * from user_constraints
    select * from user_cons_columns
    /*
    综合练习
    使用create table语句建立学生信息表
    该表共包括学号、姓名、年龄、入学日期、年级、班级、email等信息
    并且其中的学号为主键
    姓名不可以为空值
    年级默认为1年级
    email字段不可以重复
    班级的取值必须为class表中的id值
    年龄不可以为负值

    创建 频道表 channel 两个字段频道的id ,频道的名字name,频道的id是主键
    创建 视频表 video  视频的id,视频的名称,视频的上传日期,视频的播放次数,视频的评分 ,视频所属的频道Id
    视频的id是主键,视频的名称必填,视频的上传日期默认当前的系统时间,视频的评分0-5分之间,视频所属的频道Id是外键
    */

    create table channel (
    id number(10) primary key,
    name varchar2(10)
    )
    create table video (
    id number(10) primary key,
    name varchar2(10) not null,
    udate date default sysdate,
    num number(10),
    score number(2,1),
    cid number(10) references channel(id),
    constraint check_score check(score>=0 and score<=5)
    )
    insert into channel (id,name) values (1,'happy')
    insert into video (id,name,num,score,cid) values (1,'love',1,2,1)
    insert into video (id,name,num,score,cid) values (2,'you',1,2.5,1)
    select * from video
    delete from video


    create table channel(
    id number(4) primary key,
    name varchar2(10)
    );
    create table video(
     id number(4) primary key,
    channel_id number(4),
     name varchar2(10) not null,
     shangchuan_date date default sysdate,
     time number(3),
     score number(2) check(score>=0 and score<=5),
    constraint video_channel foreign key(channel_id)references channel(id)
    );

    create table channel(
       id number(2),
       name varchar2(10),
       constraint pk_channel primary key(id)
    )
    create table video(
       id number(4) primary key,
       name varchar2(20) not null,
       upload_date date default sysdate,
       display_number number(2),
       score number(2) check(score>0 and score<6),
       channelId number(2) references channel(id)
    )
    insert into channel values(1,'娱乐')
    insert into video(id,name,displaynumber,score,channelId) values(3,'嘻嘻',2,1,1)

    --更新一行数据:update
    update student set name='zhangyu' where id = 10012
    update student set id = 10014 where id = 10011
    update student set grade = 2 where name = 'zhangyu'
    update student set name = '张哥哥' where id = 10011
    select * from student

    --删除一行数据:delete
    delete from student where id = 10012
    delete from student where id = 10011
    insert into student (id,name) values (10011,'zhangfei')
    insert into student (id,name) values (10013,'zhangyu')
    insert into student (id,name) values (10014,'zhanggege')
    insert into student (id,name) values (10012,'zhangmm')
    delete from student where id = 10014
    delete from student where name = 'zhangmm'
    select * from student
    --修改表结构或其约束条件

    --添加/修改/删除字段
    --增加一个家庭住址的字段

    alter table student add(addr varchar2(100) )

    --修改新增的addr字段的精度
    alter table student modify(addr varchar2(200))
    --修改addr字段名称:
    alter table student rename column addr to zhang

    --新增的addr字段进行删除
    alter table student drop column zhang

    --添加/删除约束
    --添加class_id外键约束
    alter table student add constraint unique_email unique(email)
    alter table student add constraint sys_110 primary key(class)
    --删除class_id外键约束
    alter table student drop constraint SYS_C005319
    alter table student drop constraint SYS_C005268
    alter table student drop constraint sys_110
    --在name字段上添加非空约束
    alter table student modify(name varchar2(20) not null ) --前提是字段中还没有写入空值。
    --将name字段上的非空约束去除
    alter table student modify(name varchar2(20))
    alter table student drop constraint unique_email
    alter table student drop constraint SYS_C005261
    desc student


    --删除表
    delete from student

    --创建索引
    --索引可以加快排序数据,加快搜索。
    --要点:能改善检索操作的性能,一般用于数据过滤和数据排序。
    --对stu表中的name字段建立索引
    create index index_name on student(name)
    select name from student
    --对stu表中email、class两个字段的组合上建立索引
    create index index_email_class on student(email,class)
    --删除索引
    drop index index_name

    --视图
    --创建视图
    --平均薪水的等级最低的部门名称

    --每个部门的平均薪水的等级 3条
    --select * from salgrade
    select deptno,avg_sal,grade
    from
    (select deptno ,avg(sal) avg_sal from emp group by deptno)
    inner join salgrade on avg_sal between losal and hisal
    --最低等级
    select min(grade)
    from
    (select deptno ,avg(sal) avg_sal from emp group by deptno)
    inner join salgrade on avg_sal between losal and hisal
    --如果这个部门平均薪水的等级=最低等级

    --部门no -》 部门名称
    select dname from dept
    where deptno=(
      select deptno
      from
      (select deptno ,avg(sal) avg_sal from emp group by deptno)
      inner join salgrade on avg_sal between losal and hisal
    where grade=(
          select min(grade)
          from
          (select deptno ,avg(sal) avg_sal from emp group by deptno)
          inner join salgrade on avg_sal between losal and hisal
          )
    )

    --创建视图
    create view dept_grade as
      select deptno,grade
      from
      (select deptno ,avg(sal) avg_sal from emp group by deptno)
      inner join salgrade on avg_sal between losal and hisal


    select dname from dept
    where deptno=(
      select deptno
      from 
         dept_grade
      where grade=(
          select min(grade)
          from
          dept_grade
    )
    )
    --删除视图

    --序列
    --创建序列
    --使得student表中的id自增
    create sequence seq_student_xx start with 1 increment by 1

    --使用序列

    insert into student (id) values (seq_student_xx.NEXTVAL)
    select * from student
    select seq_student_id.CURRVAL from  dual
    --删除序列
    drop sequence seq_student_xx

    版权声明:QQ:597507041

  • 相关阅读:
    CDH版本大数据集群下搭建的Hue详细启动步骤(图文详解)
    如何正确且成功破解跨平台数据库管理工具DbVisualizer?(图文详解)
    [转]【HTTP】Fiddler(二)
    [转]jQuery UI Dialog Modal Popup Yes No Confirm example in ASP.Net
    [转]artDialog
    [转]GridView排序——微软提供Sort
    [转]GridView中直接新增行、编辑和删除
    [转]asp.net的ajax以及json
    [转]JQuery Ajax 在asp.net中使用总结
    [转]Jquery easyui开启行编辑模式增删改操作
  • 原文地址:https://www.cnblogs.com/spzhangfei/p/4801785.html
Copyright © 2011-2022 走看看