create table emp2 ( empno number(4),
ename varchar2(10),
job varchar2(9),
mgr number(4),
hiredate date,
sal number(7,2),
comm number(7,2),
deptno number(2)
);
-----------------------------------------------------------------------------------------------------------
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7369, 'SMITH', 'CLERK', 7902, to_date('17-12-1980', 'dd-mm-yyyy'), 800.00, null, 20);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7499, 'ALLEN', 'SALESMAN', 7698, to_date('20-02-1981', 'dd-mm-yyyy'), 1600.00, 300.00, 30);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7521, 'WARD', 'SALESMAN', 7698, to_date('22-02-1981', 'dd-mm-yyyy'), 1250.00, 500.00, 30);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7566, 'JONES', 'MANAGER', 7839, to_date('02-04-1981', 'dd-mm-yyyy'), 2975.00, null, 20);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7654, 'MARTIN', 'SALESMAN', 7698, to_date('28-09-1981', 'dd-mm-yyyy'), 1250.00, 1400.00, 30);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7698, 'BLAKE', 'MANAGER', 7839, to_date('01-05-1981', 'dd-mm-yyyy'), 2850.00, null, 30);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7782, 'CLARK', 'MANAGER', 7839, to_date('09-06-1981', 'dd-mm-yyyy'), 2450.00, null, 10);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7788, 'SCOTT', 'ANALYST', 7566, to_date('19-04-1987', 'dd-mm-yyyy'), 3000.00, null, 20);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7839, 'KING', 'PRESIDENT', null, to_date('17-11-1981', 'dd-mm-yyyy'), 5000.00, null, 10);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7844, 'TURNER', 'SALESMAN', 7698, to_date('08-09-1981', 'dd-mm-yyyy'), 1500.00, 0.00, 30);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7876, 'ADAMS', 'CLERK', 7788, to_date('23-05-1987', 'dd-mm-yyyy'), 1100.00, null, 20);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7900, 'JAMES', 'CLERK', 7698, to_date('03-12-1981', 'dd-mm-yyyy'), 950.00, null, 30);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7902, 'FORD', 'ANALYST', 7566, to_date('03-12-1981', 'dd-mm-yyyy'), 3000.00, null, 20);
insert into emp2 (EMPNO, ENAME, JOB, MGR, HIREDATE, SAL, COMM, DEPTNO)
values (7934, 'MILLER', 'CLERK', 7782, to_date('23-01-1982', 'dd-mm-yyyy'), 1300.00, null, 10);
=============================================================================================================================
create table dept2 ( deptno number(2),
dname varchar2(14),
loc varchar2(13)
);
----------------------------------------------------
insert into dept2 (DEPTNO, DNAME, LOC)
values (10, 'ACCOUNTING', 'NEW YORK');
insert into dept2 (DEPTNO, DNAME, LOC)
values (20, 'RESEARCH', 'DALLAS');
insert into dept2 (DEPTNO, DNAME, LOC)
values (30, 'SALES', 'CHICAGO');
insert into dept2 (DEPTNO, DNAME, LOC)
values (40, 'OPERATIONS', 'BOSTON');
============================================================
create table salgrade2 ( grade number,
losal number,
hisal number
);
--------------------------------------------------
insert into salgrade2 (GRADE, LOSAL, HISAL)
values (1, 700, 1200);
insert into salgrade2 (GRADE, LOSAL, HISAL)
values (2, 1201, 1400);
insert into salgrade2 (GRADE, LOSAL, HISAL)
values (3, 1401, 2000);
insert into salgrade2 (GRADE, LOSAL, HISAL)
values (4, 2001, 3000);
insert into salgrade2 (GRADE, LOSAL, HISAL)
values (5, 3001, 9999);
========================================================
select * from emp2;
select * from dept2;
select * from salgrade2;
=====================================
select * from emp2; --employee2 员工表
select * from dept2; --department2 部门表
select * from salgrade2; -- salary grade2 工资等级表
-----------------------------------------------------
emp2
empno 员工编号
ename 员工姓名
job 工作/工种
mgr manager上级编号
hiredate 入职日期
sal salary 工资
comm 奖金/津贴
deptno 部门编号
---------------------
dept2
deptno 部门号
dname 部门名称
loc 所在地
---------------------------
salgrade2
grade 等级
losal lowest salary 最低工资
hisal high salary 最高工资
=============================================
DML 数据操作语句：insert update delete
新增：insert into
insert into 表名 values();
insert into 表名(列) 子查询;
insert into emp94(eid,ename) select 1122,'abc' from dual
union
select 1123,'abd' from dual
union
select 1124,'acd' from dual;
create table emp94(eid integer,
ename varchar(10),
birth date,
classno number(2));
select * from emp94;
insert into emp94(eid,classno) values(1234,11);
insert into emp94(eid,classno) select empno,deptno from emp;
更改： update
update 表名 set 列名=值;
update 表名 set 列名=值 where ……;
update 表名 set 列1=值1,列2=值2,…… where ……;
update 表名 set 列=子查询 where ……;
update 表名 set 列1=子查询,列2=子查询,…… where ……;
update emp2 set sal = 9000,deptno=40 where job = 'CLERK';
把emp中，员工的工资翻倍 奖金在原奖金基础上+500 ：
update emp2 set sal=sal*2,comm=nvl(comm,0)+500;
把SMITH 的工资改成与KING 一样：
update emp2 set sal = (select sal from emp2 where ename = 'KING')
where ename = 'SMITH';
把ALLEN 改成 与CLARK同部门：
update emp set deptno = (select deptno from emp where ename='CLARK')
where ename = 'ALLEN';
把与BLAKE 同工作的员工的上级，改成SCOTT：
update emp set mgr = SCOTT的empno
where job = BLAKE的job;
把处于平均工资以下的员工，都调到BOSTON (部门的loc)：
update emp set deptno = (select deptno from dept where loc='BOSTON')
where sal < 平均工资;
删除:
delete from 表名; 删除整张表的数据
delete from 表名 where ……; 删除符合where条件的数据
delete from emp2 where deptno = 10;
select * from emp2;
数据库事务:
事务由一句DDL语句或一组DML语句组成；
DDL事务 create alter drop truncate
DML事务 insert update delete
DML事务，以执行第一句DML语句为开始，以手动commit/rollback为结束
DDL事务，语句执行结果是自动提交commit，不能rollback
DML事务---锁
DML语句执行之后，commit之前：
1）当前用户/当前窗口能够看到语句执行结果
2）其他用户窗口看不到
3）结果是可以回退的(rollback)
4）数据状态，加锁的状态--资源争用
---锁的处理 sysdba
update emp set sal = 9000 where deptno =10;
select * from emp;
