oracle的简单代码

--创建用户

create user lhy1 identified by passwd123

--表空间

default tablespace users

--临时表空间

temporary tablespace temp;

--给用户权限

grant create session to lhy1;

grant resource,connect to lhy1;

-----------------------------************************----------------------------

--创建表

create table student(stu_id number,stu_name varchar2(100));

create table kemu(km_id number,km_name varchar2(100));

create table chengji(cj_id number,km_id number,stu_id number,fs number

);

--加主键外键

alter table student add constraint pri_stu primary key (stu_id);

alter table kemu add constraint pri_km primary key(km_id);

alter table chengji add constraint fore_km foreign key(km_id) references kemu(km_id)

alter table chengji add constraint fore_stu foreign key(stu_id) references student

(stu_id)

--创建序列

create sequence seq_stu_id

increment by 1

start with 1

nomaxvalue

nominvalue

nocache;

create sequence seq_km_id

increment by 1

start with 1

nomaxvalue

nominvalue

nocache

create sequence seq_cj_id

increment by 1

start with 1

nomaxvalue

nominvalue

nocache

--添加，实现id自动增长

insert into student values(seq_stu_id.nextval,'刘辉要1');

insert into student values(seq_stu_id.nextval,'刘辉要2');

insert into student values(seq_stu_id.nextval,'刘辉要3');

select * from student for update;

insert into kemu values (seq_km_id.nextval,'数学');

insert into kemu values (seq_km_id.nextval,'语文');

insert into kemu values (seq_km_id.nextval,'英语');

select * from kemu for update;

insert into chengji values(seq_cj_id.nextval,1,1,98);

insert into chengji values(seq_cj_id.nextval,1,2,90);

insert into chengji values(seq_cj_id.nextval,1,3,88);

insert into chengji values(seq_cj_id.nextval,2,1,98);

insert into chengji values(seq_cj_id.nextval,2,2,90);

insert into chengji values(seq_cj_id.nextval,2,3,88);

insert into chengji values(seq_cj_id.nextval,3,1,98);

insert into chengji values(seq_cj_id.nextval,3,2,90);

insert into chengji values(seq_cj_id.nextval,3,3,88);

delete from chengji;

select * from chengji;

--查询学生 和他的各科成绩

with sql1

as

(select c.stu_id ,k.km_name,c.fs from kemu k inner join chengji c on c.km_id=k.km_id)

select s.stu_id,s.stu_name,sql1.km_name,sql1.fs from student s inner join sql1 on

s.stu_id=sql1.stu_id order by s.stu_id;

--查询没有选课的学生 及没有选的课 使用集合 并集，差集，交集

with t

as (select s.stu_id ,k.km_id from student s,kemu k minus select c.stu_id,c.km_id from

chengji c)

select s.stu_name ,k.km_name from student s,kemu k where (s.stu_id,k.km_id) in (select *

from t) order by s.stu_id;

------------------------********************-------------------------

create table test(id number,name varchar2(100),age number, constraint p_k primary key(id));

alter table test add constraint u_k unique(name);

alter table test modify age default 20;

--alter table test modify name default null;

insert into test (id,name) values (1,'lhy');

--设置自动增长

create sequence user_seq1

start with 1

increment by 1

nomaxvalue

nominvalue

nocache;

--删除序列

drop sequence user_seq;

--查询序列

Select * From user_objects Where object_type='SEQUENCE';

create or replace trigger tr_user1

before insert on test--test为表名

for each row

begin

select user_seq1.nextval into :new.id from dual;

end;

--删除触发器

drop trigger tr_user1;

--查询触发器

Select * From user_objects Where object_type='TRIGGER';

delete from test;

--插入

insert into test (name) values ('lhy3');

select * from test;