type和create type

type和create type

异同点：
      create type 可在库中生成一个长期有效的自定义类型对象，而type作用域仅限于语句块中；
      两者都可以自定义数据类型；

各种type实例：

--【create type】*****************************************************************
--①简单 type _object--------------------------------------
create or replace type test_type01 as object(
       a varchar2(20),
       b varchar2(20),
       c number(10));

--②简单 type _varray--------------------------------------
create or replace type test_type02 as varray(10) of test_type01;

--③简单 type _table--------------------------------------
create or replace type test_type03 as table of test_type02;

--④创建带映射函数的【object】类型
--create type as object(member) --------------------------------------
create or replace type test_type01 as object (
       a varchar2(10),
       b varchar2(10),
       member function aaa(a in varchar2,b in varchar2) return varchar2
       );
create or replace type body test_type01 as
       member function aaa(a in varchar2,b in varchar2) return varchar2 is
       begin
           return a||b;
       end;
end;
--用法一：create table of type
create table test_type_table01 of test_type01;
insert into test_type_table01 values('a','a');
insert into test_type_table01 select test_type01('','') from dual;
commit;

select * from test_type_table01;
select ee.a,ee.aaa('dd','ee') from test_type_table01 ee;

--用法二：create table(typename.type)
create table test_type_table02(
       a number(10),
       test_t test_type01
       );
insert into test_type_table02 values(1,test_type01('a','a'));
insert into test_type_table02 select 2,test_type01('b','b') from dual;
commit;

select * from test_type_table02;
select rr.a,rr.test_t,rr.test_t.a,rr.test_t.aaa('dd','ee') from test_type_table02 rr;

--⑤创建【table】类型
--create type as table --------------------------------------
--用法一：
create or replace type test_type02 as object (
       a varchar2(10),
       b varchar2(10)
       ) not final;
create or replace type test_type03 as table of test_type02;

create table test_type_table03(
       id number(10),
       test_ty test_type03
       )nested table test_ty store as test_ty_table;--test_ty_table表示嵌套表【名称可随意取？】；

insert into test_type_table03 values(1,test_type03(test_type02('a','a')));
insert into test_type_table03 select 2,test_type03(test_type02('b','b'),test_type02('c','c')) from dual;
commit;

select * from test_type_table03;
select aa.id,aa.test_ty from test_type_table03 aa;
select * from table(select aa.test_ty from test_type_table03 aa where aa.id=2);
/*       --无效sql
select * from table(select aa.test_ty from test_type_table03 aa where aa.id in(1,2));--ORA-01427: 单行子查询返回多个行
select * from test_ty_table;--ORA-22812: 无法参考嵌套表列的存储表
truncate table test_type_table03;--truncate 无效，因为其中有集合
*/

--用法二：
create or replace type test_type04 as table of varchar2(10);--varchar2要限定字符数，否则会报错
create or replace type test_type05 as object(
       a number(10),
       test_ test_type04
       );
create table test_type_table02 of test_type05
       nested table test_ store as test_ty_table02;--test_为【table】类型的变量    

/*--在用法二下这种定义表的语句不被允许,是因为test_type05为object？
create table test_type_table04(
       id number(10),
       test_t test_type05
       )nested table test_ store as test_ty_table02;
*/

insert into test_type_table02 values(test_type05(1,test_type04('a')));
insert into test_type_table02 select test_type05(2,test_type04('b','c')) from dual;
commit;

drop table test_type_table02;
drop type test_type04;
drop type test_type05;

select * from test_type_table02;
select * from table(select tt.test_ from test_type_table02 tt where tt.a=2);
select aa.a,aa.test_ from test_type_table02 aa;

--⑥创建【varray】类型
--create type as varray --------------------------------------
create or replace type test_type07 as varray(4) of varchar2(10);

create table test_type_table03(
       id number(10),
       test_ test_type07
       );

insert into test_type_table03 values(1,test_type07('a'));
insert into test_type_table03
       select 2,test_type07('b','c') from dual
       union all
       select 3,test_type07('d','e','f') from dual;
commit;
select * from test_type_table03;
select kk.* from table(select tt.test_ from test_type_table03 tt where id=3) kk;

--⑦创建混合自定义类型
create or replace type test_type08 as varray(4) of varchar2(10);
create or replace type test_type09 as table of varchar2(10);--varchar2要限定字符数，否则会报错
create or replace type test_type10 as object(
       a number(10),
       test_ test_type08,
       test_1 test_type09
       );

create table test_type_table05 of test_type10
       nested table test_1 store as test_ty_table05;
insert into test_type_table05 values(1,test_type08('a'),test_type09('a'));
insert into test_type_table05 select 2,test_type08('b','c'),test_type09('b') from dual;
--注意以下两种写法，效果相同
insert into test_type_table05 select test_type10(3,test_type08('b','c','d','e'),test_type09('c','d')) from dual;
insert into test_type_table05 select 4,test_type08('b','c','d','e'),test_type09('c','d') from dual;

select * from test_type_table05;
select * from table(select tt.test_ from test_type_table05 tt where tt.a=3);
select * from table(select tt.test_1 from test_type_table05 tt where tt.a=3);

--【type】*****************************************************************
--①简单 type _object--------------------------------------
declare type test_type_ is record(
       a emp.empno%type,
       b emp.ename%type,
       c emp.job%type);
       test_ test_type_;
begin
       test_.a:=123;
       test_.b:='abc';
       test_.c:='def';
       dbms_output.put_line(test_.a||test_.b||test_.c);
       select empno,ename,job into test_ from emp where empno='';
       dbms_output.put_line(test_.a||test_.b||test_.c);
end;
--②简单 type _varray--------------------------------------
declare
      type test_type_02 is varray(5) of varchar2(10);
      test_ test_type_02;
begin
      test_:=test_type_02('a','b','c','d');
      dbms_output.put_line(test_(1)||test_(2)||test_(3)||test_(4));
end;

--③简单 type _table--------------------------------------
declare
      type test_type_03 is table of emp%rowtype;
      test_ test_type_03;
begin
      select empno,ename,job,mgr,hiredate,sal,comm,deptno bulk collect into test_ from emp where empno='';
      for i in test_.first..test_.last loop
          dbms_output.put_line(test_(i).empno||test_(i).ename||test_(i).job);
      end loop;
end;

--【type ref cursor】*****************************************************************
--①强类型和弱类型ref游标--------------------------------------
declare
  --弱类型ref游标
  type test_type is ref cursor;
  --强类型ref游标（有return返回值）
  type test_type_ is ref cursor return emp%rowtype;
  test_ test_type;
  test__ test_type_;
  emp_ emp%rowtype;
  emp__ emp%rowtype;
begin
  open test_ for select * from emp;
  loop
       fetch test_ into emp_;
       dbms_output.put_line(emp_.ename);
       exit when test_%notfound;
  end loop;
  close test_;
  dbms_output.put_line('##############################');
  open test__ for select * from emp;
  loop
       fetch test__ into emp__;
       dbms_output.put_line(emp__.ename);
       exit when test__%notfound;
  end loop;
  close test__;
end;

--②将ref游标作为返回值--------------------------------------
--创建函数（返回游标）
create or replace function test_func_ref return sys_refcursor as
       test_ref sys_refcursor;
begin
       open test_ref for select * from emp;
       return test_ref;
end;
--调用函数
declare a sys_refcursor;
        b emp%rowtype;
begin
        a:=test_func_ref;
        loop
          fetch a into b;
          exit when a%notfound;
          dbms_output.put_line(b.empno);
        end loop;
end;

--sys_refcursor是9i后系统定义的一个refcursor，用于过程中返回结果集