day06—oracle基础

今天初学oracle数据库，正好串起之前学过的Myeclipse的知识，复习也是进阶。

1、Oracle数据类型

1）number

2）char

3）varchar2

4）date

2、表控制语句

1）create table table_name()

2）drop table table_name;

3) alter table table_name;add(createdate column);4

4) insert into table_name;(属性) values (值);

5）update table_name;set 属性=值（欲修改）, where 属性=值（条件）;

3、oracle字符串操作

1）字符串合并：CONCAT和 ||

2）大小写转换：UPPER、LOWER和INITCAP

3）字符串截去：TRIM

4）字符串补位：LPAD、RPAD

5）字符串截取：SUBSTR

4、oracle数值操作

1）数值四舍五入：ROUND

2）数值截取：TRUNC

3）数值取余：MOD

5、oracle日期操作

1）select to_char(sysdate（当前时间）,'yyyy-mm-dd day hh24:mi:ss') from dual

作用：将当前时间转换为2016-3-2 星期三 0:22:56 这样的格式

2）select to_date('2014-8-25','yyyy-mm-dd') from dual

作用：将字符串2014-8-25转换为默认格式：25-8-14 时间。

6、oracle修改默认日期格式：

alter session set nls_date_format='yyyy/mm/dd';

可以将当前会话oracle默认的日期格式'dd-mm-yy'转化为'yyyy/mm/dd';



接下来，用今天所学，实现一个数据表格：

create table emp(empno number(4,0) primary key,ename varchar2(10),
job varchar2(9),mgr number(4,0),hiredate date,sal number(7,2),comm
number(7,2),deptno number(2,0));
--1
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7369,'smith','clerk',7902,to_date('1980-12-17','yyyy/mm/dd'),
800.00,'',20);
commit;
--2
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7499,'allen','salesman',7698,to_date('1981-2-20','yyyy/mm/dd'),
1600.00,'300.00',20);
commit;
--3
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7521,'ward','salesman',7698,to_date('1981-2-22','yyyy/mm/dd'),
1250.00,'500.00',30);
commit;
--4
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7566,'jones','manager',7839,to_date('1981-4-2','yyyy/mm/dd'),
2975.00,'',20);
commit;
--5
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7654,'martin','salesman',7698,to_date('1981-9-28','yyyy/mm/dd'),
1250,'1400.00',30);
commit;
--6
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7698,'blake','manager',7839,to_date('1981-5-1','yyyy/mm/dd'),
2850,'',30);
commit;
--7
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7782,'clark','manager',7839,to_date('1981-6-9','yyyy/mm/dd'),
2450,'',10);
commit;
--8
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7788,'scott','analyst',7566,to_date('1987-4-19','yyyy/mm/dd'),
3000,'',20);
commit;
--9
insert into emp(empno,ename,job,hiredate,sal,comm,deptno) values 
(7839,'king','president',to_date('1981-11-17','yyyy/mm/dd'),
5000,'',10);
commit;
--10
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7844,'turner','salesman',7698,to_date('1981-9-8','yyyy/mm/dd'),
5000,'0.00',30);
commit;
--11
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7876,'adams','clerk',7788,to_date('1987-5-23','yyyy/mm/dd'),
1100,'',20);
commit;
--12
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7900,'james','clerk',7698,to_date('1981-12-3','yyyy/mm/dd'),
950,'',30);
commit;
--13
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7902,'ford','analyst',7566,to_date('1981-12-3','yyyy/mm/dd'),
3000,'',20);
commit;
--14
insert into emp(empno,ename,job,mgr,hiredate,sal,comm,deptno) values 
(7934,'miller','clerk',7782,to_date('1982-1-23','yyyy/mm/dd'),
1300,'',10);
commit;
select empno as "员工ID",ename as "员工姓名", job as "职位",mgr as "员工管理者ID",
hiredate as "入职日期",sal as "薪资",comm as "绩效",deptno as "员工所在部门的ID"
from emp;

alter session set nls_date_format='yyyy/mm/dd';

表格如下：