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  • oracle基础学习(1)

    -解锁用户,需要使用dba权限
    conn sys/1234 as dba;

    alert user scott account unlock;
    /

    --initcap方法,实现字符串首字符大写,其余字符小写,受空格,逗号等非字母符号限制 
    select initcap('hello word,da jia hao!') Hello from dual;


    --平均工资大于2000的分组
    select avg_sal,deptno from 
    (select avg(sal) avg_sal,deptno from emp group by deptno) 
    where avg_sal >2000;

    having语句用法:
    select avg(sal),deptno from emp group by deptno having avg(sal) > 2000;
    /

    --求部门中哪些人的薪水最高
    select ename,sal from emp e join (select max(sal) max_sal,deptno from emp group by deptno) t on (e.deptno = t.deptno and e.sal = t.max_sal)
    /
    --求部门平均薪水的等级
    select deptno,avg_sal,grade from salgrade s join (select avg(sal) avg_sal,deptno from emp group by deptno) t on (t.avg_sal between s.losal and hisal)
    /
    --求部门平均的薪水等级
    select avg(t.grade) avg_grade,t.deptno from (select ename,deptno,grade from emp e join salgrade s on (e.sal between s.losal and s.hisal)) t group by t.deptno
    /
    --雇员中哪些人是经理人
    select ename from emp where empno in (select distinct mgr from emp)
    /
    --不用函数求薪水的最高值
    select distinct ename,sal from emp where sal not in (select distinct e1.sal from emp e1 join emp e2 on (e1.sal <e2.sal))
    /
    select t.ename,t.sal from (select ename,sal from emp order by sal desc) t where rownum<2(当最大薪水有多值时不对)
    /
    --求平均薪水最高的部门的部门编号
    select deptno,avg_sal from 
    (select avg(sal) avg_sal,deptno from emp group by deptno) 
    where avg_sal = 
    (select max(avg_sal) from (select avg(sal) avg_sal,deptno from emp group by deptno)
    )

    等同于:
    select deptno,avg_sal from
    (select avg(sal) avg_sal,deptno from emp group by deptno)
    where avg_sal = 
    (select max(avg(sal)) from emp group by deptno)
    /
    --求平均薪水最高的部门名称
    select dname from dept where deptno = 
    (
    select deptno from 
    ( select deptno,avg(sal) avg_sal from emp group by deptno ) 
    where avg_sal =
    ( select max(avg_sal) from 
    (select avg(sal) avg_sal,deptno from emp group by deptno) 
    )
    )
    /
    --求平均薪水的等级最低的部门的部门名称
    select t.deptno,t.dname from dept t where t.deptno = 
    (
    select deptno from 
    (
    select deptno,grade,avg_sal from 
    (select avg(sal) avg_sal,deptno from emp group by deptno) 
    join salgrade s on (avg_sal between s.losal and s.hisal)
    where grade = 
    (
    select min(grade) from 
    (
    select deptno,grade,avg_sal from 
    (select avg(sal) avg_sal,deptno from emp group by deptno) 
    join salgrade s on (avg_sal between s.losal and s.hisal)
    )
    )

    )
    等同于:
    select t.deptno,dname,avg_sal,grade from
    (
    select deptno,avg_sal,grade from
    (select avg(sal) avg_sal,deptno from emp group by deptno) t1
    join salgrade s on (t1.avg_sal between s.losal and s.hisal)
    ) t
    join dept d on (t.deptno = d.deptno)
    where t.grade = 
    (
    select min(grade) from 
    (
    select deptno,avg_sal,grade from
    (select avg(sal) avg_sal,deptno from emp group by deptno) t1
    join salgrade s on (t1.avg_sal between s.losal and s.hisal)

    )


    /
    --求平均等级最低的部门名称
    select t.dname from dept t where t.deptno = 

    select deptno from 
    ( select deptno,avg(grade) avg_grade from
    ( select e.deptno,s.grade from emp e join salgrade s on (e.sal between s.losal and s.hisal)

    group by deptno

    where avg_grade = 
    ( select min(avg_grade) from 
    (select deptno,avg(grade) avg_grade from 
    (select e.deptno,s.grade from emp e join salgrade s on (e.sal between s.losal and s.hisal) 

    group by deptno 


    )
    /
    --创建视图,首先赋予权限
    conn sys/1234 as sysdba; sys不校验密码,任意密码即可。
    grant create table,create view to scott;

    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);

    因此,求平均等级最低的部门名称可以用一下语句替换:
    select t.deptno,d.dname,avg_sal,grade from
    v_dept_avg_sal_info t 
    join dept d on (t.deptno = d.deptno)
    where t.grade = (select min(grade) from v_dept_avg_sal_info);

    /

    --求部门经理人中平均薪水最低的部门名称(经理人指empno存在于mgr中的员工)

    select dname, t.deptno, avg_sal
    from (select deptno, avg(sal) avg_sal
    from emp
    where empno in (select distinct mgr from emp where mgr is not null)
    group by deptno) t
    join dept d
    on (d.deptno = t.deptno)
    where t.avg_sal =
    (select min(avg_sal)
    from (select deptno, avg(sal) avg_sal
    from emp
    where empno in
    (select distinct mgr from emp where mgr is not null)
    group by deptno))

    创建视图v_mgr_sal_info,如下: 
    create view v_mgr_sal_info as
    select deptno, avg(sal) avg_sal
    from emp
    where empno in (select distinct mgr from emp where mgr is not null)
    group by deptno;

    select dname, t.deptno, avg_sal
    from v_mgr_sal_info t
    join dept d
    on (d.deptno = t.deptno)
    where t.avg_sal = (select min(avg_sal) from v_mgr_sal_info);

    /

    --求比普通员工的最高薪水还高的经理人名称:

    select ename
    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))
    /

    --删除用户
    drop user mc cascade;
    --备份用户 
    backup scott
    exp
    --创建用户
    create user mc identified by 1234 default tablespace quota 10M on users;
    --赋予权限
    grant create session,create table,create view to mc;
    --导入数据
    imp


    --快速备份表,即创建一个一样的表
    create table dept1 as select * from dept;


    --求薪水值最高的前五名雇员;
    select ename,sal from 
    (select ename,sal from emp order by sal desc ) 
    where rownum<6;

    /
    --求薪水值第六名到第十名的雇员;
    select ename,sal from
    (select ename,sal,rownum r from
    (select ename ,sal from emp order by sal desc)
    )
    where r>5 and r <11;

    /

    /*
    *
    * 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,既学过1号课程又学过2号课程所有学生的姓名。
    * 请用标准SQL语言写出答案。
    */
    答案:
    1,
    select sname from s join sc on (s.sno = sc.sno) join c on (c.cno = sc.cno) where c.cteacher <> '黎明';

    2,
    --学生姓名
    select sname from s where s.sno in ( select sno from sc where sc.scgrade < 60 group by sco having count(*) >=2 );
    --平均成绩
    select avg(scgrade) from sc where sc.sno in ( select sno from sc where sc.scgrade < 60 group by sco having count(*) >=2 ) group by sc.sno;

    3,
    select sname from s where s.sno in (select sno from sc where sc.cno =1 and sno in ( selcet distinct sno from sc where cno = 2 ) );


    --
    一个事务(transaction)起始于一条dml语句(insert,update,delete),终止于①commit语句;②ddl语句(create,drop)和dcl语句(grant,remove);
    正常断开连接时,transaction自动提交,非正常断开连接,transaction自动回滚。


    --创建一张学生表 --约束类型:不为空约束,主键约束,外键约束,唯一性约束,check约束
    create table stu1 --字段级约束条件
    (
    id number(6),
    name varchar2(20) constraint stu_name_nn not null,--不为空约束
    sex number(1),
    age number(3),
    sdate date,
    grade number(2) default 1,
    class number(4) references class(id),--外键约束,外键约束被参考条件必须是主键
    email varchar2(50) unique --唯一约束条件
    );

    create table stu 
    (
    id number(6) primary key,--主键约束
    name varchar2(20) constraint stu_name_nn not null,--不为空约束
    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(name,email), --表级约束
    constraint stu_class_fk_foregin key (class) references class(id)
    );


    create table class
    (
    id number(4) primary key,
    name varchar2(20) not null
    );


    alert table stu add(addr varchar2(100));

    alert table stu drop (addr);

    alert table stu modify (addr varchar2(120));

    alert table stu add constraint stu_class_fk foreign key (class) references class(id);

    --创建与删除索引
    create index idx_stu_email on stu (email);


    drop index idx_stu_email;
    /

    三范式:
    ①要有主键,列不可分;
    ②不能存在部分依赖;(联合主键情况下,非主键列不能部分依赖于主键)即每张表只描述一件事
    ③确保每列都和主键列直接相关,而不是间接相关。

    --pl/sql结构化语言

    --变量声明的规则:
    1,变量名不能使用保留字,如from、select等;
    2,第一个字符必须是字母;
    3,变量名最多包含30个字符;
    4,不要与数据库的表或者列同名;
    5,每一行只能声明一个变量。

    --常用变量类型:
    1,binary_integer,整数,主要用来计数而不是用来表示字段类型;
    2,number,数字类型;
    3,char,定长字符串;
    4,varchar2,变长字符串;
    5,date,日期;
    6,long,长字符串,最长2GB;
    7,boolean,布尔类型,可以取值为true、false和null值。


    --最简单的语句块
    begin
    dbms_output.put_line('HelloWorld');
    end;
    /

    在dos命令窗口输出命令:
    set serveroutput on;

    --简单的PL/SQL语句块
    declare
    v_name varchar2(20);
    begin
    v_name := 'myname';
    dbms_output.put_line(v_name);
    end;
    /

    --异常处理
    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;
    /

    --变量声明
    declare
    v_temp number(1);
    v_count binary_integer := 0;
    v_sal number(7,2) := 4000.00;
    v_date date := sysdate;
    v_pi constant number(3,2) := 3.14;

    v_valid boolean := false;
    v_name varchar2(20) not null := 'MyName';
    begin
    dbms_output.put_line('v_temp value:' || v_sal);
    end;
    /
    注意:dbms_output.put_line命令不能打印布尔类型。

    --变量声明,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;
    /

    --Table变量类型,相当于java中的数组。
    declare
    type type_table_emp_empno is table of emp.empno%type index by binary_integer;
    v_empnos type_table_emp_empno;

    begin
    v_empnos(0) := 7369;
    v_empnos(2) := 7839;
    v_empnos(-1) := 9999;
    dbms_output.put_line(v_empnos(-1));
    end;
    /


    --Table类型实例讲解

    使用记录类型变量只能保存一行数据,这限制了SELECT语句的返回行数,如果SELECT语句返回多行就会错。Oracle提供了另外一种自定义类型,也就是表类型,它是对记录类型的扩展,允许处理多行数据,类似于表。
    创建表类型的语法如下:
    TYPE table_name IS TABLE OF data_type [ NOT NULL ]
    INDEX BY BINARY_INTEGER ;
    语法说明如下:
    --table_name 创建的表类型名称。
    --IS TABLE 表示创建的是表类型。
    --data_type 可以是任何合法的PL/SQL数据类型,例如varchar2。
    --INDEX BY BINARY_INTEGER 指定系统创建一个主键索引,用于引用表类型变量中的特定行。

    使用表类型的例子:

    例一:直接对表类型变量赋值

    declare
    type my_emp is table of scott.emp%rowtype
    index by binary_integer;
    new_emp my_emp;
    begin
    new_emp(1).empno:=6800;
    new_emp(1).ename:='tracy';
    new_emp(1).job:='clerk';
    new_emp(1).sal:=2500;
    new_emp(2).empno:=6900;
    new_emp(2).ename:='luck';
    new_emp(2).job:='manager';
    new_emp(2).sal:=4000;
    dbms_output.put_line(new_emp(1).empno ||','||new_emp(1).ename||','||new_emp(1).job||
    ','||new_emp(1).sal);
    dbms_output.put_line(new_emp(2).empno ||','||new_emp(2).ename||','||new_emp(2).job||
    ','||new_emp(2).sal);
    end;
    /

    例二:使用表类型变量的方法:变量名.方法名[索引号]

    declare
    type my_emp is table of scott.emp%rowtype
    index by binary_integer;
    new_emp my_emp;
    begin
    new_emp(1).empno:=6800;
    new_emp(1).ename:='tracy';
    new_emp(1).job:='clerk';
    new_emp(1).sal:=2500;
    new_emp(2).empno:=6900;
    new_emp(2).ename:='luck';
    new_emp(2).job:='manager';
    new_emp(2).sal:=4000;
    dbms_output.put_line(new_emp.first||','||new_emp.count||','||new_emp.last);
    dbms_output.put_line(new_emp(1).empno ||','||new_emp(1).ename||','||new_emp(1).job||
    ','||new_emp(1).sal);
    dbms_output.put_line(new_emp(2).empno ||','||new_emp(2).ename||','||new_emp(2).job||
    ','||new_emp(2).sal);
    --new_emp.delete(1);
    dbms_output.put_line(new_emp.next(1));
    end;
    //

    例三:与游标结合使用
    declare
    type my_emp is table of scott.emp%rowtype
    index by binary_integer;
    new_emp my_emp;
    v_num number:=0;
    cursor cur_emp is select empno,ename,job,sal from scott.emp;

    begin
    for v_emp in cur_emp loop
    v_num:=v_num+1;
    select * into new_emp(v_num) from scott.emp
    where ename=v_emp.ename;
    end loop;


    for i in 1..new_emp.count loop
    dbms_output.put_line(new_emp(i).empno ||','||new_emp(i).ename||','||new_emp(i).job||
    ','||new_emp(i).sal);
    end loop;
    end;
    /
    注意:不能直接对表变量赋值:select * into new_emp from scott.emp where deptno=30; 这种赋值方法是错的,赋值需要使用下标,如上面的的例子。


    --Record变量类型
    declare
    type type_record_dept is record
    (
    deptno dept.deptno%type,
    dname dept.dname%type,
    loc dept.loc%type
    );
    v_temp type_record_dept;
    begin
    v_temp.deptno := 50;
    v_temp.dname := 'aaaa';
    v_temp.loc := 'bj';
    dbms_output.put_line(v_temp.deptno || ' ' || v_temp.dname);
    end;
    /

    --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;
    /

    --sql语句的运用
    --select语句
    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;
    /
    --select语句
    declare
    v_emp emp%rowtype;
    begin
    select * into v_emp from emp where empno = 7369;
    dbms_output.put_line(v_emp.ename);
    end;
    /

    --insert语句
    declare
    v_deptno dept.deptno%type := 50;
    v_dname dept.dname%type := 'aaaa';
    v_loc dept.loc%type := 'bj';
    begin
    insert into dept values(v_deptno,v_dname,v_loc);
    commit;
    end;
    /

    --update语句
    declare
    v_deptno emp.deptno%type := 50;
    v_count number;
    begin
    update emp set sal = sal/2 where deptno = v_deptno;
    --select deptno into v_deptno from emp where empno = 7369;
    --select count(*) into v_count from emp;
    dbms_output.put_line(sql%rowcount || '条记录被影响');
    commit;
    end;
    /
    注意:sql代表刚刚执行过的语句,rowcount代表刚执行过的语句影响的记录。


    --PL/SQL中执行DDL语句
    begin
    execute immediate 'create table T (nnn varchar2(20) default ''aaa'' )';
    end;
    /

    --if语句
    --取出7369的薪水,如果<1200,则输出'low',如果<2000,则输出'middle',否则'high';
    declare
    v_sal emp.sal%type;
    begin
    select sal into v_sal from emp where empno = 7369;
    if(v_sal<1200) then
    dbms_output.put_line('low');
    elsif(v_sal<2000) then
    dbms_output.put_line('middle');
    else
    dbms_output.put_line('high');
    end if;
    end;
    /

    --循环
    --loop when循环,相当于java中的do..while循环
    declare
    i binary_integer := 1;
    begin
    loop
    dbms_output.put_line(i);
    i := i+1;
    exit when (i >= 11);
    end loop;
    end;
    /
    --while循环
    declare
    j binary_integer := 1;
    begin
    while j < 11 loop
    dbms_output.put_line(j);
    j := j+1;
    end loop;
    end;
    /
    --for循环
    declare
    k binary_integer := 1;
    begin
    for k in 1..10 loop
    dbms_output.put_line(k);
    end loop;
    end;
    /
    declare
    k binary_integer := 1;
    begin
    for k in reverse 1..10 loop --逆序
    dbms_output.put_line(k);
    end loop;
    end;
    /

    --错误处理
    declare
    v_temp number(4);
    begin
    select empno into v_temp from emp where deptno = 10;
    exception
    when too_many_rows then
    dbms_output.put_line('太多记录了');
    when others then
    dbms_output.put_line('没数据');
    end;
    /

    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('没数据');
    end;
    /
    --创建错误日志
    create table errorlog
    (
    id number primary key,
    errcode number,
    errmsg varchar2(1024),
    errdate date
    );
    /
    create sequence seq_errorlog_id start with 1 increment by 1;
    /
    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;
    /

    --游标
    declare
    cursor c is --声明游标
    select * from emp;
    v_emp c%rowtype;
    begin
    open c; --打开游标
    fetch c into v_emp;
    dbms_output.put_line(v_emp.ename);
    close c; --关闭游标
    end;
    /
    --游标,循环
    declare
    cursor c is
    select * from emp;
    v_emp c%rowtype;
    begin
    open c;
    loop
    fetch c into v_emp;
    exit when (c%notfound);
    dbms_output.put_line(v_emp.ename);
    end loop;
    close c;
    end;
    /
    --while循环
    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;
    /
    --for循环
    declare
    cursor c is
    select * from emp;
    begin
    for v_emp in c loop
    dbms_output.put_line(v_emp.ename);
    end loop;
    end;
    /
    --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;
    begin
    for v_temp in c(30,'CLERK') loop
    dbms_output.put_line(v_temp.ename);
    end loop;
    end;
    /
    --可更新的游标
    declare
    cursor c
    is
    select * from emp2 for update;
    begin
    for v_temp in c loop
    if (v_temp.sal < 2000) then
    update emp2 set sal = sal * 2 where current of c;
    elsif (v_temp.sal = 5000) then
    delete from emp2 where current of c;
    end if;
    end loop;
    commit;
    end;
    /

    --oracle集合类型的first、next、prior、 last方法

    创建一个存储过程,用于产生oracle三种集合类型的数据

    create or replace procedure plch_main
    is
    TYPE NESTED_T IS TABLE OF NUMBER;--嵌套表类型
    TYPE ASSOCIATIVE_T IS TABLE OF NUMBER INDEX BY BINARY_INTEGER; --索引表类型
    TYPE VARRAYS_T IS VARRAY(10) OF NUMBER; --变长数组类型

    lst_nested nested_t:=nested_t(-2000,null,3500);
    lst_associative associative_t;--索引表类型的集合不能直接赋值 可以从其特性来理解(可以是稀疏排列的)
    lst_varrays varrays_t:=varrays_t(-2000,null,3500);
    begin

    lst_associative(1):=-2000;
    lst_associative(3):=null;--注意,这里没有lst_associative数组第二个元素
    lst_associative(4):=3500;

    dbms_output.put_line('以下为嵌套表的输出内容:');
    dbms_output.put_line('lst_nested(1) :'||lst_nested(1));
    dbms_output.put_line('lst_nested(2) :'||lst_nested(2));
    dbms_output.put_line('lst_nested(3) :'||lst_nested(3));
    dbms_output.put('lst_nested.first-1:'); 
    dbms_output.put_line(lst_nested.first-1);
    dbms_output.put_line('lst_nested.first :'||lst_nested.first);
    dbms_output.put_line('lst_nested.prior(1):'||lst_nested.prior(1));
    dbms_output.put_line('lst_nested.next(1):'||lst_nested.next(1));
    dbms_output.put_line('lst_nested.next(2):'||lst_nested.next(2));
    dbms_output.put_line('lst_nested.next(3):'||lst_nested.next(3));
    dbms_output.put_line('lst_nested.last :'||lst_nested.last);

    dbms_output.put_line('以下为索引表的输出内容:'); 
    dbms_output.put_line('lst_associative(1) :'||lst_associative(1));
    dbms_output.put_line('lst_associative(3) :'||lst_associative(3));
    dbms_output.put_line('lst_associative(4) :'||lst_associative(4));
    dbms_output.put('lst_associative.first-1:');
    dbms_output.put_line(lst_associative.first-1);
    dbms_output.put_line('lst_associative.first :'||lst_associative.first);
    dbms_output.put_line('lst_associative.prior(1):'||lst_associative.prior(1));
    dbms_output.put_line('lst_associative.next(1):'||lst_associative.next(1));
    dbms_output.put_line('lst_associative.next(2):'||lst_associative.next(2));
    dbms_output.put_line('lst_associative.next(4):'||lst_associative.next(4));
    dbms_output.put_line('lst_associative.last :'||lst_associative.last);

    dbms_output.put_line('以下为变长数组的输出内容:');
    dbms_output.put_line('lst_varrays(1) :'||lst_varrays(1));
    dbms_output.put_line('lst_varrays(2) :'||lst_varrays(2));
    dbms_output.put_line('lst_varrays(3) :'||lst_varrays(3));
    dbms_output.put('lst_varrays.first-1:');
    dbms_output.put_line(lst_varrays.first-1);
    dbms_output.put_line('lst_varrays.first :'||lst_varrays.first);
    dbms_output.put_line('lst_varrays.prior(1):'||lst_varrays.prior(1));
    dbms_output.put_line('lst_varrays.next(1):'||lst_varrays.next(1));
    dbms_output.put_line('lst_varrays.next(2):'||lst_varrays.next(2));
    dbms_output.put_line('lst_varrays.next(3):'||lst_varrays.next(3));
    dbms_output.put_line('lst_varrays.last :'||lst_varrays.last);
    end;
    /

    存储过程编译成功,以下调用并查看结果。
    特别注意三种数组中第一个元素的prior方法、最后一个元素的next方法都是可以执行出来的;
    并且索引表类型中未定义的元素序列也有prior、next方法。

    SQL> exec plch_main;

    以下为嵌套表的输出内容:
    lst_nested(1) :-2000
    lst_nested(2) :
    lst_nested(3) :3500
    lst_nested.first-1:0
    lst_nested.first :1
    lst_nested.prior(1):
    lst_nested.next(1):2
    lst_nested.next(2):3
    lst_nested.next(3):
    lst_nested.last :3
    以下为索引表的输出内容:
    lst_associative(1) :-2000
    lst_associative(3) :
    lst_associative(4) :3500
    lst_associative.first-1:0
    lst_associative.first :1
    lst_associative.prior(1):
    lst_associative.next(1):3
    lst_associative.next(2):3
    lst_associative.next(4):
    lst_associative.last :4
    以下为变长数组的输出内容:
    lst_varrays(1) :-2000
    lst_varrays(2) :
    lst_varrays(3) :3500
    lst_varrays.first-1:0
    lst_varrays.first :1
    lst_varrays.prior(1):
    lst_varrays.next(1):2
    lst_varrays.next(2):3
    lst_varrays.next(3):
    lst_varrays.last :3

    PL/SQL procedure successfully completed

    .first方法是数组中第一个元素的下标值(序列值)
    .prior(n)方法是数组中第n个元素的前一个元素的下标值(序列值)

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  • 原文地址:https://www.cnblogs.com/mengyuxin/p/4660679.html
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