1.创建一个表: (Oracle database) create table stu ( id int, name varchar(20), sex varchar(10), age int ); 2.向已有的表中插入一行数据: insert into stu(id,name,sex,age) values(1,‘huhu‘,‘man‘,20); insert into stu(id,name,sex,age) values(212,‘huiny‘,‘woman‘,22); insert into stu(id,name,sex,age) values(315,‘灰灰‘,‘男‘,23); 3. 查寻表中元素 1.查询所有 select *from stu; 2.查询部分(某几列) select id,sex from stu; 3.查询部分(某几行) select *from stu where id=1; 4.查询表中记录条数 select count(*) from stu; 4.删除 1.删除表中记录 delete from stu where id=1; 2.删除表 drop table stu; 5.修改 update from ...; 6.约束 1.在表中直接添加约束 primary key(主键) unique(唯一) check(检查) 例:check(stusex in(‘男‘,‘女‘)) not null(非空) foreign key(外键) 1.数据复用 2.字段可以拆成两列 1.两个表有关系,用外键 2.(一般)在元素多的一方加外键,(偶尔)考虑方向问题,不要造成数据重复 1.创建司机表 create table driver_table ( flowid number(12) primary key, driver_name varchar2(90), driver_sex varchar2(20) ); ;创建车辆表 create table vehicle_table ( vehicle_id number(12) primary key, vehicle_type varchar2(90), vehcile_num varchar2(90), driver_id number(12) references driver_table(flowid) ); 3.删除两个表 drop table driver_table; drop table vehicle_table; 4.向两个表中插入数据 insert into driver_table(flowid,driver_name,driver_sex) values(1,‘yangee‘,‘nan‘); insert into vehicle_table(vehicle_id,vehicle_type,vehcile_num,driver_id) values(1,‘sang‘,‘yu-a3i3i‘,1); insert into vehicle_table(vehicle_id,vehicle_type,vehcile_num,driver_id) values(2,‘sang‘,‘yu-a3i3i‘,2); 5. select v.vehicle_type, v.vehcile_num, d.driver_name, d.driver_sex from vehicle_table v left outer join driver_table d on v.driver_id=d.flowid; 作业:1.练习多个表之间的增删改成, 2.设计你的项目,利用讲的原则 3.每个组设计一个数据库文档(数据库设计说明书) 自练 /*by myself*/ create table student ( id int, name varchar2(8) ); create table course ( id int, cname varchar2(8) ); drop table student; drop table course; insert into student(id,name) values(1,‘张三‘); insert into student(id,name) values(2,‘李四‘); insert into student(id,name) values(3,‘王五‘); insert into course(id,cname) values(1,‘足球‘); insert into course(id,cname) values(2,‘音乐‘); insert into course(id,cname) values(4,‘美术‘); /* 左连接 */ select * from student left join course on student.ID=course.ID; insert into student(id,name) values(1,‘huiny‘); insert into course(id,cname) values(1,‘tuny‘); /*右连接*/ select * from student right join course on student.ID=course.ID; /*完全外连接*/ select * from student full join course on student.ID=course.ID; /*内连接*/ select * from student inner join course on student.ID=course.ID; select student.id,student.name,course.cname from student inner join course on student.ID=course.ID; /*交叉连接*/ select * from student cross join course; select * from student cross join course where student.ID=course.ID; /*链接:http://www.dedecms.com/knowledge/data-base/sql-server/2012/0709/2872.html */ select s.Name,C.Cname from student_course as sc left join student as s on s.Sno=sc.Sno left join course as c on c.Cno=sc.Cno; 查询不重复记录 select distinct id from student; select distinct name from student; order by 排序 /*默认从小到大排序*/ select *from student order by id; update 使用 update student set name=‘huhu‘ where id=1; 显示所有表 select * from all_tables; /***************************2015/07/20***************************/ 1.创建表空间(oracle放表的地方)/*表空间名:account */ create tablespace account datafile ‘c:/account.dbf‘ size 25M; 2.创建用户(与表空间绑定)/*用户名:account 密码:account 用户空间:account */ create user account identified by account default tablespace account; 3.用户授权 grant resource,connect to account; /*授权*/ /**创建自己的表空间**/ create tablespace huiny datafile ‘c:/huiny.dbf‘ size 25M; create user huhu identified by huhu default tablespace huiny; grant resource,connect to huhu;
时间: 2024-10-10 10:14:27