關於 pipe row的用法2009/12/30 14:53
發表於:2007.11.28 11:14
分類: oracle10g
出處:http://flysky0814.itpub.net/post/35477/419443
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管道化表函數必須返回一個集合。在函數中,PIPE ROW 語句被用來返回該集合的單個元素,該函數必須以一個空的 RETURN 語句結束,以表明它已經完成。一旦我們創建了上述函數,我們就可以使用 TABLE 操作符從 SQL 查詢中調用它。
管道化表函數經常被用來把數據從一種類型轉化成另一種類型。
下面是用 Pipelined Table 實現 split 函數的例子:
CREATE OR REPLACE TYPE ty_str_split IS TABLE OF VARCHAR2 (4000);
CREATE OR REPLACE FUNCTION fn_split (p_str IN VARCHAR2, p_delimiter IN VARCHAR2)
RETURN ty_str_split PIPELINED
IS
j INT := 0;
i INT := 1;
len INT := 0;
len1 INT := 0;
str VARCHAR2 (4000);
BEGIN
len := LENGTH (p_str);
len1 := LENGTH (p_delimiter);
WHILE j < len
LOOP
j := INSTR (p_str, p_delimiter, i);
IF j = 0
THEN
j := len;
str := SUBSTR (p_str, i);
PIPE ROW (str);
IF i >= len
THEN
EXIT;
END IF;
ELSE
str := SUBSTR (p_str, i, j - i);
i := j + len1;
PIPE ROW (str);
END IF;
END LOOP;
RETURN;
END fn_split;
/
測試:SELECT * FROM TABLE (fn_split ('1;;12;;123;;1234;;12345', ';;'));
結果:
1
12
123
1234
12345
又一個簡單的例子:CREATE TYPE mytype AS OBJECT (
field1 NUMBER,
field2 VARCHAR2 (50)
);
CREATE TYPE mytypelist AS TABLE OF mytype;
CREATE OR REPLACE FUNCTION pipelineme
RETURN mytypelist PIPELINEDIS
v_mytype mytype;
BEGIN
FOR v_count IN 1 .. 20
LOOP
v_mytype := mytype (v_count, 'Row ' || v_count);
PIPE ROW (v_mytype); END LOOP;
RETURN;
END pipelineme;
SELECT * FROM TABLE (pipelineme);
FIELD1 FIELD2
------ ------------------------
1 Row 1
2 Row 2
3 Row 3
4 Row 4
5 Row 5
6 Row 6
7 Row 7
8 Row 8
9 Row 9
10 Row 10
11 Row 11
12 Row 12
13 Row 13
14 Row 14
15 Row 15
16 Row 16
17 Row 17
18 Row 18
19 Row 19
20 Row 20
create or replace type dlsys.split_tbl as table of varchar2(32767);
create or replace function dlsys.dlsplit(p_list varchar2,
p_del varchar2 := ',')
return dlsys.split_tbl
pipelined is
l_idx pls_integer;
l_list varchar2(32767) := p_list;
begin
loop
l_idx := instr(l_list, p_del);
if l_idx > 0 then
pipe row(substr(l_list, 1, l_idx - 1));
l_list := substr(l_list, l_idx + length(p_del));
else
pipe row(l_list);
exit;
end if;
end loop;
return;
end dlsplit;
-----------------------------------------------------------------------------------------------
DECLARE
a ty_str_split ;
BEGIN
select fn_split ('1;;12;;123;;1234;;12345;;w', ';;') into a from dual ;
a(1) := 'ell';
dbms_output.put_line(a(100));
null;
END;
作者:NewSea 出處:http://newsea.cnblogs.com/ QQ,MSN:[email protected] 如無特別標記說明,均爲NewSea原創,版權私有,翻載必糾。歡迎交流,轉載,但要在頁面明顯位置給出原文連接。謝謝。 |