尚学堂马士兵Oracle教程笔记
- 检查Oracle安装
- 首先,以超级管理员的身份登录oracle
- sqlplus sys/bjsxt as sysdba
- 然后,解除对scott用户的锁
- alter user scott account unlock;
- 那么这个用户名就能使用了。
- (默认全局数据库名orcl)
- 1、select ename, sal * 12 from emp; //计算年薪
- 2、select 2*3 from dual; //计算一个比较纯的数据用dual表
- 3、select sysdate from dual; //查看当前的系统时间
- 4、select ename, sal*12 anuual_sal from emp; //给搜索字段更改名称(双引号 keepFormat 别名有特殊字符,要加双引号)。
- 5、任何含有空值的数学表达式,最后的计算结果都是空值。
- 6、select ename||sal from emp; //(将sal的查询结果转化为字符串,与ename连接到一起,相当于Java中的字符串连接)
- 7、select ename||'afasjkj' from emp; //字符串的连接
- 8、select distinct deptno from emp; //消除deptno字段重复的值
- 9、select distinct deptno , job from emp; //将与这两个字段都重复的值去掉
- 10、select * from emp where deptno=10; //(条件过滤查询)
- 11、select * from emp where empno > 10; //大于 过滤判断
- 12、select * from emp where empno <> 10 //不等于 过滤判断
- 13、select * from emp where ename > 'cba'; //字符串比较,实际上比较的是每个字符的AscII值,与在Java中字符串的比较是一样的
- 14、select ename, sal from emp where sal between 800 and 1500; //(between and过滤,包含800 1500)
- 15、select ename, sal, comm from emp where comm is null; //(选择comm字段为null的数据)
- 16、select ename, sal, comm from emp where comm is not null; //(选择comm字段不为null的数据)
- 17、select ename, sal, comm from emp where sal in (800, 1500,2000); //(in 表范围)
- 18、select ename, sal, hiredate from emp where hiredate > '02-2月-1981'; //(只能按照规定的格式写)
- 19、select ename, sal from emp where deptno =10 or sal >1000;
- 20、select ename, sal from emp where deptno =10 and sal >1000;
- 21、select ename, sal, comm from emp where sal not in (800, 1500,2000); //(可以对in指定的条件进行取反)
- 22、select ename from emp where ename like '%ALL%'; //(模糊查询)
- 23、select ename from emp where ename like '_A%'; //(取第二个字母是A的所有字段)
- 24、select ename from emp where ename like '%/%%'; //(用转义字符/查询字段中本身就带%字段的)
- 25、select ename from emp where ename like '%$%%' escape '$'; //(用转义字符/查询字段中本身就带%字段的)
- 26、select * from dept order by deptno desc; (使用order by desc字段 对数据进行降序排列 默认为升序asc);
- 27、select * from dept where deptno <>10 order by deptno asc; //(我们可以将过滤以后的数据再进行排序)
- 28、select ename, sal, deptno from emp order by deptno asc, ename desc; //(按照多个字段排序 首先按照deptno升序排列,当detpno相同时,内部再按照ename的降序排列)
- 29、select lower(ename) from emp; //(函数lower() 将ename搜索出来后全部转化为小写);
- 30、select ename from emp where lower(ename) like '_a%'; //(首先将所搜索字段转化为小写,然后判断第二个字母是不是a)
- 31、select substr(ename, 2, 3) from emp; //(使用函数substr() 将搜素出来的ename字段从第二个字母开始截,一共截3个字符)
- 32、select chr(65) from dual; //(函数chr() 将数字转化为AscII中相对应的字符)
- 33、select ascii('A') from dual; //(函数ascii()与32中的chr()函数是相反的 将相应的字符转化为相应的Ascii编码) )
- 34、select round(23.232) from dual; //(函数round() 进行四舍五入操作)
- 35、select round(23.232, 2) from dual; //(四舍五入后保留的小数位数 0 个位 -1 十位)
- 36、select to_char(sal, '$99,999.9999')from emp; //(加$符号加入千位分隔符,保留四位小数,没有的补零)
- 37、select to_char(sal, 'L99,999.9999')from emp; //(L 将货币转化为本地币种此处将显示¥人民币)
- 38、select to_char(sal, 'L00,000.0000')from emp; //(补零位数不一样,可到数据库执行查看)
- 39、select to_char(hiredate, 'yyyy-MM-DD HH:MI:SS') from emp; //(改变日期默认的显示格式)
- 40、select to_char(sysdate, 'yyyy-MM-DD HH:MI:SS') from dual; //(用12小时制显示当前的系统时间)
- 41、select to_char(sysdate, 'yyyy-MM-DD HH24:MI:SS') from dual; //(用24小时制显示当前的系统时间)
- 42、select ename, hiredate from emp where hiredate > to_date('1981-2-20 12:24:45','YYYY-MM-DD HH24:MI:SS'); //(函数to-date 查询公司在所给时间以后入职的人员)
- 43、select sal from emp where sal > to_number('$1,250.00', '$9,999.99'); //(函数to_number()求出这种薪水里带有特殊符号的)
- 44、select ename, sal*12 + nvl(comm,0) from emp; //(函数nvl() 求出员工的"年薪 + 提成(或奖金)问题")
- 45、select max(sal) from emp; // (函数max() 求出emp表中sal字段的最大值)
- 46、select min(sal) from emp; // (函数max() 求出emp表中sal字段的最小值)
- 47、select avg(sal) from emp; //(avg()求平均薪水);
- 48、select to_char(avg(sal), '999999.99') from emp; //(将求出来的平均薪水只保留2位小数)
- 49、select round(avg(sal), 2) from emp; //(将平均薪水四舍五入到小数点后2位)
- 50、select sum(sal) from emp; //(求出每个月要支付的总薪水)
- /////////////////////////组函数(共5个):将多个条件组合到一起最后只产生一个数据//////min() max() avg() sum() count()/////////////////////////////
- 51、select count(*) from emp; //求出表中一共有多少条记录
- 52、select count(*) from emp where deptno=10; //再要求一共有多少条记录的时候,还可以在后面跟上限定条件
- 53、select count(distinct deptno) from emp; //统计部门编号前提是去掉重复的值
- ////////////////////////聚组函数group by() //////////////////////////////////////
- 54、select deptno, avg(sal) from emp group by deptno; //按照deptno分组,查看每个部门的平均工资
- 55、select max(sal) from emp group by deptno, job; //分组的时候,还可以按照多个字段进行分组,两个字段不相同的为一组
- 56、select ename from emp where sal = (select max(sal) from emp); //求出
- 57、select deptno, max(sal) from emp group by deptno; //搜素这个部门中薪水最高的的值
- //////////////////////////////////////////////////having函数对于group by函数的过滤 不能用where//////////////////////////////////////
- 58、select deptno, avg(sal) from emp group by deptno having avg(sal) >2000; (order by )//求出每个部门的平均值,并且要 > 2000
- 59、select avg(sal) from emp where sal >1200 group by deptno having avg(sal) >1500 order by avg(sal) desc;//求出sal>1200的平均值按照deptno分组,平均值要>1500最后按照sal的倒序排列
- 60、select ename,sal from emp where sal > (select avg(sal) from emp); //求那些人的薪水是在平均薪水之上的。
- 61、select ename, sal from emp join (select max(sal) max_sal ,deptno from emp group by deptno) t on (emp.sal = t.max_sal and emp.deptno=t.deptno); //查询每个部门中工资最高的那个人
- ///////////////////////////////等值连接//////////////////////////////////////
- 62、select e1.ename, e2.ename from emp e1, emp e2 where e1.mgr = e2.empno; //自连接,把一张表当成两张表来用
- 63、select ename, dname from emp, dept; //92年语法 两张表的连接 笛卡尔积。
- 64、select ename, dname from emp cross join dept; //99年语法 两张表的连接用cross join
- 65、select ename, dname from emp, dept where emp.deptno = dept.deptno; // 92年语法 表连接 + 条件连接
- 66、select ename, dname from emp join dept on(emp.deptno = dept.deptno); // 新语法
- 67、select ename,dname from emp join dept using(deptno); //与66题的写法是一样的,但是不推荐使用using : 假设条件太多
- ///////////////////////////////////////非等值连接///////////////////////////////////////////
- 68、select ename,grade from emp e join salgrade s on(e.sal between s.losal and s.hisal); //两张表的连接 此种写法比用where更清晰
- 69、select ename, dname, grade from emp e
- join dept d on(e.deptno = d.deptno)
- join salgrade s on (e.sal between s.losal and s.hisal)
- where ename not like '_A%'; //三张表的连接
- 70、select e1.ename, e2.ename from emp e1 join emp e2 on(e1.mgr = e2.empno); //自连接第二种写法,同62
- 71、select e1.ename, e2.ename from emp e1 left join emp e2 on(e1.mgr = e2.empno); //左外连接 把左边没有满足条件的数据也取出来
- 72、select ename, dname from emp e right join dept d on(e.deptno = d.deptno); //右外连接
- 73、select deptno, avg_sal, grade from (select deptno, avg(sal) avg_sal from emp group by deptno) t join salgrade s on (t.avg_sal between s.losal and s.hisal);//求每个部门平均薪水的等级
- 74、select ename from emp where empno in (select mgr from emp); // 在表中搜索那些人是经理
- 75、select sal from emp where sal not in(select distinct e1.sal from emp e1 join emp e2 on(e1.sal < e2.sal)); // 面试题 不用组函数max()求薪水的最大值
- 76、select deptno, max_sal from
- (select avg(sal) max_sal,deptno from emp group by deptno)
- where max_sal =
- (select max(max_sal) from
- (select avg(sal) max_sal,deptno from emp group by deptno)
- );//求平均薪水最高的部门名称和编号。
- 77、select t1.deptno, grade, avg_sal from
- (select deptno, grade, avg_sal from
- (select deptno, avg(sal) avg_sal from emp group by deptno) t
- join salgrade s on(t.avg_sal between s.losal and s.hisal)
- ) t1
- join dept on (t1.deptno = dept.deptno)
- where t1.grade =
- (
- select min(grade) from
- (select deptno, grade, avg_sal from
- (select deptno, avg(sal) avg_sal from emp group by deptno) t
- join salgrade s on(t.avg_sal between s.losal and s.hisal)
- )
- )//求平均薪水等级最低的部门的名称 哈哈 确实比较麻烦
- 78、create view v$_dept_avg_sal_info as
- select deptno, grade, avg_sal from
- (select deptno, avg(sal) avg_sal from emp group by deptno) t
- join salgrade s on(t.avg_sal between s.losal and s.hisal);
- //视图的创建,一般以v$开头,但不是固定的
- 79、select t1.deptno, grade, avg_sal from v$_dept_avg_sal_info t1
- join dept on (t1.deptno = dept.deptno)
- where t1.grade =
- (
- select min(grade) from
- v$_dept_avg_sal_info t1
- )
- )//求平均薪水等级最低的部门的名称 用视图,能简单一些,相当于Java中方法的封装
- 80、---创建视图出现权限不足时候的解决办法:
- conn sys/admin as sysdba;
- 显示:连接成功 Connected
- grant create table, create view to scott;
- 显示: 授权成功 Grant succeeded
- 81、-------求比普通员工最高薪水还要高的经理人的名称 -------
- select ename, sal from emp where empno in
- (select distinct mgr from emp where mgr is not null)
- and sal >
- (
- select max(sal) from emp where empno not in
- (select distinct mgr from emp where mgr is not null)
- )
- 82、---面试题:比较效率
- select * from emp where deptno = 10 and ename like '%A%';//好,将过滤力度大的放在前面
- select * from emp where ename like '%A% and deptno = 10;
- 83、-----表的备份
- create table dept2 as select * from dept;
- 84、-----插入数据
- insert into dept2 values(50,'game','beijing');
- ----只对某个字段插入数据
- insert into dept2(deptno,dname) values(60,'game2');
- 85、-----将一个表中的数据完全插入另一个表中(表结构必须一样)
- insert into dept2 select * from dept;
- 86、-----求前五名员工的编号和名称(使用虚字段rownum 只能使用 < 或 = 要使用 > 必须使用子查询)
- select empno,ename from emp where rownum <= 5;
- 86、----求10名雇员以后的雇员名称--------
- select ename from (select rownum r,ename from emp) where r > 10;
- 87、----求薪水最高的前5个人的薪水和名字---------
- select ename, sal from (select ename, sal from emp order by sal desc) where rownum <=5;
- 88、----求按薪水倒序排列后的第6名到第10名的员工的名字和薪水--------
- select ename, sal from
- (select ename, sal, rownum r from
- (select ename, sal from emp order by sal desc)
- )
- where r>=6 and r<=10
- 89、----------------创建新用户---------------
- 1、backup scott//备份
- exp//导出
- 2、create user
- create user guohailong identified(认证) by guohailong default tablespace users quota(配额) 10M on users
- grant create session(给它登录到服务器的权限),create table, create view to guohailong
- 3、import data
- imp
- 90、-----------事务回退语句--------
- rollback;
- 91、-----------事务确认语句--------
- commit;//此时再执行rollback无效
- 92、当正常断开连接的时候例如exit,事务自动提交。 当非正常断开连接,例如直接关闭dos窗口或关机,事务自动提交
- 93、有3个表S,C,SC
- S(SNO,SNAME)代表(学号,姓名)
- C(CNO,CNAME,CTEACHER)代表(课号,课名,教师)
- SC(SNO,CNO,SCGRADE)代表(学号,课号成绩)
- 问题:
- 1,找出没选过“黎明”老师的所有学生姓名。
- 2,列出2门以上(含2门)不及格学生姓名及平均成绩。
- 3,即学过1号课程有学过2号课所有学生的姓名。
- 答案:
- 1、
- select sname from s join sc on(s.sno = sc.sno) join c on (sc.cno = c.cno) where cteacher <> '黎明';
- 2、
- select sname where sno in (select sno from sc where scgrade < 60 group by sno having count(*) >=2);
- 3、
- select sname from s where sno in (select sno, from sc where cno=1 and cno in
- (select distinct sno from sc where cno = 2);
- )
- 94、--------------创建表--------------
- create table stu
- (
- id number(6),
- name varchar2(20) constraint stu_name_mm not null,
- sex number(1),
- age number(3),
- sdate date,
- grade number(2) default 1,
- class number(4),
- email varchar2(50) unique
- );
- 95、--------------给name字段加入 非空 约束,并给约束一个名字,若不取,系统默认取一个-------------
- create table stu
- (
- id number(6),
- name varchar2(20) constraint stu_name_mm not null,
- sex number(1),
- age number(3),
- sdate date,
- grade number(2) default 1,
- class number(4),
- email varchar2(50)
- );
- 96、--------------给nameemail字段加入 唯一 约束 两个 null值 不为重复-------------
- create table stu
- (
- id number(6),
- name varchar2(20) constraint stu_name_mm not null,
- sex number(1),
- age number(3),
- sdate date,
- grade number(2) default 1,
- class number(4),
- email varchar2(50) unique
- );
- 97、--------------两个字段的组合不能重复 约束:表级约束-------------
- create table stu
- (
- id number(6),
- name varchar2(20) constraint stu_name_mm not null,
- sex number(1),
- age number(3),
- sdate date,
- grade number(2) default 1,
- class number(4),
- email varchar2(50),
- constraint stu_name_email_uni unique(email, name)
- );
- 98、--------------主键约束-------------
- create table stu
- (
- id number(6),
- name varchar2(20) constraint stu_name_mm not null,
- sex number(1),
- age number(3),
- sdate date,
- grade number(2) default 1,
- class number(4),
- email varchar2(50),
- constraint stu_id_pk primary key (id),
- constraint stu_name_email_uni unique(email, name)
- );
- ?99、--------------外键约束 被参考字段必须是主键 -------------
- create table stu
- (
- id number(6),
- name varchar2(20) constraint stu_name_mm not null,
- sex number(1),
- age number(3),
- sdate date,
- grade number(2) default 1,
- class number(4) references class(id),
- email varchar2(50),
- constraint stu_class_fk foreign key (class) references class(id),
- constraint stu_id_pk primary key (id),
- constraint stu_name_email_uni unique(email, name)
- );
- create table class
- (
- id number(4) primary key,
- name varchar2(20) not null
- );
- 100、---------------修改表结构,添加字段------------------
- alter table stu add(addr varchar2(29));
- 101、---------------删除字段--------------------------
- alter table stu drop (addr);
- 102、---------------修改表字段的长度------------------
- alter table stu modify (addr varchar2(50));//更改后的长度必须要能容纳原先的数据
- 103、----------------删除约束条件----------------
- alter table stu drop constraint 约束名
- 104、-----------修改表结构添加约束条件---------------
- alter table stu add constraint stu_class_fk foreign key (class) references class (id);
- 105、---------------数据字典表----------------
- desc dictionary;
- //数据字典表共有两个字段 table_name comments
- //table_name主要存放数据字典表的名字
- //comments主要是对这张数据字典表的描述
- 105、---------------查看当前用户下面所有的表、视图、约束-----数据字典表user_tables---
- select table_name from user_tables;
- select view_name from user_views;
- select constraint_name from user-constraints;
- 106、-------------索引------------------
- create index idx_stu_email on stu (email);// 在stu这张表的email字段上建立一个索引:idx_stu_email
- 107、---------- 删除索引 ------------------
- drop index index_stu_email;
- 108、---------查看所有的索引----------------
- select index_name from user_indexes;
- 109、---------创建视图-------------------
- create view v$stu as selesct id,name,age from stu;
- 视图的作用: 简化查询 保护我们的一些私有数据,通过视图也可以用来更新数据,但是我们一般不这么用 缺点:要对视图进行维护
- 110、-----------创建序列------------
- create sequence seq;//创建序列
- select seq.nextval from dual;// 查看seq序列的下一个值
- drop sequence seq;//删除序列
- 111、------------数据库的三范式--------------
- (1)、要有主键,列不可分
- (2)、不能存在部分依赖:当有多个字段联合起来作为主键的时候,不是主键的字段不能部分依赖于主键中的某个字段
- (3)、不能存在传递依赖
- ==============================================PL/SQL==========================
- 112、-------------------在客户端输出helloworld-------------------------------
- set serveroutput on;//默认是off,设成on是让Oracle可以在客户端输出数据
- 113、begin
- dbms_output.put_line('helloworld');
- end;
- /
- 114、----------------pl/sql变量的赋值与输出----
- declare
- v_name varchar2(20);//声明变量v_name变量的声明以v_开头
- begin
- v_name := 'myname';
- dbms_output.put_line(v_name);
- end;
- /
- 115、-----------pl/sql对于异常的处理(除数为0)-------------
- declare
- v_num number := 0;
- begin
- v_num := 2/v_num;
- dbms_output.put_line(v_num);
- exception
- when others then
- dbms_output.put_line('error');
- end;
- /
- 116、----------变量的声明----------
- binary_integer:整数,主要用来计数而不是用来表示字段类型 比number效率高
- number:数字类型
- char:定长字符串
- varchar2:变长字符串
- date:日期
- long:字符串,最长2GB
- boolean:布尔类型,可以取值true,false,null//最好给一初值
- 117、----------变量的声明,使用 '%type'属性
- declare
- v_empno number(4);
- v_empno2 emp.empno%type;
- v_empno3 v_empno2%type;
- begin
- dbms_output.put_line('Test');
- end;
- /
- //使用%type属性,可以使变量的声明根据表字段的类型自动变换,省去了维护的麻烦,而且%type属性,可以用于变量身上
- 118、---------------Table变量类型(table表示的是一个数组)-------------------
- declare
- type type_table_emp_empno is table of emp.empno%type index by binary_integer;
- v_empnos type_table type_table_empno;
- begin
- v_empnos(0) := 7345;
- v_empnos(-1) :=9999;
- dbms_output.put_line(v_empnos(-1));
- end;
- 119、-----------------Record变量类型
- declare
- type type_record_dept is record
- (
- deptno dept.deptno%type,
- dname dept.dname%type,
- loc dept.loc%type
- );
- begin
- v_temp.deptno:=50;
- v_temp.dname:='aaaa';
- v_temp.loc:='bj';
- dbms_output.put_line(v temp.deptno || ' ' || v temp.dname);
- end;
- 120、-----------使用 %rowtype声明record变量
- declare
- v_temp dept%rowtype;
- begin
- v_temp.deptno:=50;
- v_temp.dname:='aaaa';
- v_temp.loc:='bj';
- dbms_output.put_line(v temp.deptno || '' || v temp.dname)
- end;
- 121、--------------sql%count 统计上一条sql语句更新的记录条数
- 122、--------------sql语句的运用
- declare
- v_ename emp.ename%type;
- v_sal emp.sal%type;
- begin
- select ename,sal into v_ename,v_sal from emp where empno = 7369;
- dbms_output.put_line(v_ename || '' || v_sal);
- end;
- 123、 -------- pl/sql语句的应用
- declare
- v_emp emp%rowtype;
- begin
- select * into v_emp from emp where empno=7369;
- dbms_output_line(v_emp.ename);
- end;
- 124、-------------pl/sql语句的应用
- declare
- v_deptno dept.deptno%type := 50;
- v_dname dept.dname%type :='aaa';
- v_loc dept.loc%type := 'bj';
- begin
- insert into dept2 values(v_deptno,v_dname,v_loc);
- commit;
- end;
- 125、-----------------ddl语言,数据定义语言
- begin
- execute immediate 'create table T (nnn varchar(30) default ''a'')';
- end;
- 126、------------------if else的运用
- declare
- v_sal emp.sal%type;
- begin
- select sal into v_sal from emp where empno = 7369;
- if(v_sal < 2000) then
- dbms_output.put_line('low');
- elsif(v_sal > 2000) then
- dbms_output.put_line('middle');
- else
- dbms_output.put_line('height');
- end if;
- end;
- 127、-------------------循环 =====do while
- declare
- i binary_integer := 1;
- begin
- loop
- dbms_output.put_line(i);
- i := i + 1;
- exit when (i>=11);
- end loop;
- end;
- 128、---------------------while
- declare
- j binary_integer := 1;
- begin
- while j < 11 loop
- dbms_output.put_line(j);
- j:=j+1;
- end loop;
- end;
- 129、---------------------for
- begin
- for k in 1..10 loop
- dbms_output.put_line(k);
- end loop;
- for k in reverse 1..10 loop
- dbms_output.put_line(k);
- end loop;
- end;
- 130、-----------------------异常(1)
- declare
- v_temp number(4);
- begin
- select empno into v_temp from emp where empno = 10;
- exception
- when too_many_rows then
- dbms_output.put_line('太多记录了');
- when others then
- dbms_output.put_line('error');
- end;
- 131、-----------------------异常(2)
- declare
- v_temp number(4);
- begin
- select empno into v_temp from emp where empno = 2222;
- exception
- when no_data_found then
- dbms_output.put_line('太多记录了');
- end;
- 132、----------------------创建序列
- create sequence seq_errorlog_id start with 1 increment by 1;
- 133、-----------------------错误处理(用表记录:将系统日志存到数据库便于以后查看)
- 创建日志表:
- create table errorlog
- (
- id number primary key,
- errcode number,
- errmsg varchar2(1024),
- errdate date
- );
- declare
- v_deptno dept.deptno%type := 10;
- v_errcode number;
- v_errmsg varchar2(1024);
- begin
- delete from dept where deptno = v_deptno;
- commit;
- exception
- when others then
- rollback;
- v_errcode := SQLCODE;
- v_errmsg := SQLERRM;
- insert into errorlog values (seq_errorlog_id.nextval, v_errcode,v_errmsg, sysdate);
- commit;
- end;
- 133---------------------PL/SQL中的重点cursor(游标)和指针的概念差不多
- declare
- cursor c is
- select * from emp; //此处的语句不会立刻执行,而是当下面的open c的时候,才会真正执行
- v_emp c%rowtype;
- begin
- open c;
- fetch c into v_emp;
- dbms_output.put_line(v_emp.ename); //这样会只输出一条数据 134将使用循环的方法输出每一条记录
- close c;
- end;
- 134----------------------使用do while 循环遍历游标中的每一个数据
- declare
- cursor c is
- select * from emp;
- v_emp c%rowtype;
- begin
- open c;
- loop
- fetch c into v_emp;
- (1) exit when (c%notfound); //notfound是oracle中的关键字,作用是判断是否还有下一条数据
- (2) dbms_output.put_line(v_emp.ename); //(1)(2)的顺序不能颠倒,最后一条数据,不会出错,会把最后一条数据,再次的打印一遍
- end loop;
- close c;
- end;
- 135------------------------while循环,遍历游标
- declare
- cursor c is
- select * from emp;
- v_emp emp%rowtype;
- begin
- open c;
- fetch c into v_emp;
- while(c%found) loop
- dbms_output.put_line(v_emp.ename);
- fetch c into v_emp;
- end loop;
- close c;
- end;
- 136--------------------------for 循环,遍历游标
- declare
- cursor c is
- select * from emp;
- begin
- for v_emp in c loop
- dbms_output.put_line(v_emp.ename);
- end loop;
- end;
- 137---------------------------带参数的游标
- declare
- cursor c(v_deptno emp.deptno%type, v_job emp.job%type)
- is
- select ename, sal from emp where deptno=v_deptno and job=v_job;
- --v_temp c%rowtype;此处不用声明变量类型
- begin
- for v_temp in c(30, 'click') loop
- dbms_output.put_line(v_temp.ename);
- end loop;
- end;
- 138-----------------------------可更新的游标
- declare
- cursor c //有点小错误
- is
- select * from emp2 for update;
- -v_temp c%rowtype;
- begin
- for v_temp in c loop
- if(v_temp.sal < 2000) then
- update emp2 set sal = sal * 2 where current of c;
- else if (v_temp.sal =5000) then
- delete from emp2 where current of c;
- end if;
- end loop;
- commit;
- end;
- 139-----------------------------------procedure存储过程(带有名字的程序块)
- create or replace procedure p
- is--这两句除了替代declare,下面的语句全部都一样
- cursor c is
- select * from emp2 for update;
- begin
- for v_emp in c loop
- if(v_emp.deptno = 10) then
- update emp2 set sal = sal +10 where current of c;
- else if(v_emp.deptno =20) then
- update emp2 set sal = sal + 20 where current of c;
- else
- update emp2 set sal = sal + 50 where current of c;
- end if;
- end loop;
- commit;
- end;
- 执行存储过程的两种方法:
- (1)exec p;(p是存储过程的名称)
- (2)
- begin
- p;
- end;
- /
- 140-------------------------------带参数的存储过程
- create or replace procedure p
- (v_a in number, v_b number, v_ret out number, v_temp in out number)
- is
- begin
- if(v_a > v_b) then
- v_ret := v_a;
- else
- v_ret := v_b;
- end if;
- v_temp := v_temp + 1;
- end;
- 141----------------------调用140
- declare
- v_a number := 3;
- v_b number := 4;
- v_ret number;
- v_temp number := 5;
- begin
- p(v_a, v_b, v_ret, v_temp);
- dbms_output.put_line(v_ret);
- dbms_output.put_line(v_temp);
- end;
- 142------------------删除存储过程
- drop procedure p;
- 143------------------------创建函数计算个人所得税
- create or replace function sal_tax
- (v_sal number)
- return number
- is
- begin
- if(v_sal < 2000) then
- return 0.10;
- elsif(v_sal <2750) then
- return 0.15;
- else
- return 0.20;
- end if;
- end;
- 144-----------------------------创建触发器(trigger) 触发器不能单独的存在,必须依附在某一张表上
- //创建触发器的依附表
- create table emp2_log
- (
- ename varchar2(30) ,
- eaction varchar2(20),
- etime date
- );
- create or replace trigger trig
- after insert or delete or update on emp2 ---for each row 加上此句,每更新一行,触发一次,不加入则值触发一次
- begin
- if inserting then
- insert into emp2_log values(USER, 'insert', sysdate);
- elsif updating then
- insert into emp2_log values(USER, 'update', sysdate);
- elsif deleting then
- insert into emp2_log values(USER, 'delete', sysdate);
- end if;
- end;
- 145-------------------------------通过触发器更新数据
- create or replace trigger trig
- after update on dept
- for each row
- begin
- update emp set deptno =:NEW.deptno where deptno =: OLD.deptno;
- end;
- //////只编译不显示的解决办法 set serveroutput on;
- 145-------------------------------通过创建存储过程完成递归
- create or replace procedure p(v_pid article.pid%type,v_level binary_integer) is
- cursor c is select * from article where pid = v_pid;
- v_preStr varchar2(1024) := '';
- begin
- for i in 0..v_leave loop
- v_preStr := v_preStr || '****';
- end loop;
- for v_article in c loop
- dbms_output.put_line(v_article.cont);
- if(v_article.isleaf = 0) then
- p(v_article.id);
- end if;
- end loop;
- end;
- 146-------------------------------查看当前用户下有哪些表---
- 首先,用这个用户登录然后使用语句:
- select * from tab;
- 147-----------------------------用Oracle进行分页!--------------
- 因为Oracle中的隐含字段rownum不支持'>'所以:
- select * from (
- select rownum rn, t.* from (
- select * from t_user where user_id <> 'root'
- ) t where rownum <6
- ) where rn >3
- 148------------------------Oracle下面的清屏命令----------------
- clear screen; 或者 cle scr;
- 149-----------将创建好的guohailong的这个用户的密码改为abc--------------
- alter user guohailong identified by abc
- 当密码使用的是数字的时候可能会不行