Oracle Pipelined Function 管道函数实例

管道函数的原理，请参考oracle document:

http://docs.oracle.com/cd/E11882_01/appdev.112/e10765/pipe_paral_tbl.htm#ADDCI4686

 

先面是简单的实例，由于Pipeline 只能用array/nesttable作为返回值，所以需要创建oracle object;

这里我们使用oracle package作为接口。

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--  1. 创建包头 DDL for Package MY_TYPES

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  CREATE OR REPLACE PACKAGE MY_TYPES IS

  --1.define Object and Array of oracle type

  type lookup_row is record (idx number, text varchar2(20));

  TYPE LOOKUPS_TAB IS TABLE OF LOOKUP_ROW;

 

  --2. define function interface

  FUNCTION LOOKUPS_FN RETURN MY_TYPES.LOOKUPS_TAB  pipelined;

end My_Types;

/

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--  2. 创建包体 DDL for Package Body MY_TYPES

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  CREATE OR REPLACE PACKAGE BODY MY_TYPES IS

  --1.function

  function Lookups_Fn return My_Types.lookups_tab

    pipelined

  is

    v_row My_Types.lookup_row;

  begin

    for j in 1..10

    loop

      case j

        when 1 then v_row.idx := 1; v_row.text := 'one';

        else    v_row.idx := j; v_row.text := 'other';

      end case;

      pipe row ( v_row );

    end loop;

    RETURN;

  END LOOKUPS_FN;

  

end My_Types;

/

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--  3. 通过table函数直接调用 invoke above function

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select * from table(MY_TYPES.Lookups_Fn()) t where t.idx<8;