如何將CLOB數據類型作爲輸出返回Oracle存儲過程中的參數？

Question

我想從oracle存儲過程返回CLOB數據類型（XML數據）的輸出參數。

我的過程是這樣的

create or replace PROCEDURE myProcedure 
(
    myParam1 IN NUMBER 
,myParam2 IN NUMBER 
,myParam3 OUT CLOB 
) AS 
    xml_bits CLOB; 
BEGIN 

select xmldataColumn into xml_bits 
from myTable WHERE id = myParam1 AND SESSION_ID = myParam2; 

    IMPCPM_XML := xml_bits; 
END myProcedure; 

我編這一點，當我嘗試執行，這是給我下面的錯誤。

exact fetch returns more than requested number of rows 

如何返回一個大的xmldata作爲出參數？

在此先感謝。

Answer 1

該錯誤與返回CLOB值無關。這是查詢：

select xmldataColumn into xml_bits 
from myTable WHERE id = myParam1 AND SESSION_ID = myParam2; 

返回多行多使用SELECT ... INTO ...要求查詢返回只有一行。

你可以添加一個過濾器ROWNUM = 1：

create or replace PROCEDURE myProcedure 
(
    myParam1 IN NUMBER 
,myParam2 IN NUMBER 
,myParam3 OUT CLOB 
) AS xml_bits CLOB; 
BEGIN 
    select xmldataColumn 
    into xml_bits 
    from myTable 
    WHERE id = myParam1 
    AND SESSION_ID = myParam2 
    AND ROWNUM = 1; 
END myProcedure; 
/

或者你也可以處理該異常：

create or replace PROCEDURE myProcedure 
(
    myParam1 IN NUMBER 
,myParam2 IN NUMBER 
,myParam3 OUT CLOB 
) AS xml_bits CLOB; 
BEGIN 
    select xmldataColumn 
    into xml_bits 
    from myTable 
    WHERE id = myParam1 
    AND SESSION_ID = myParam2; 
EXCEPTION 
    WHEN TOO_MANY_ROWS THEN 
    xml_bits := NULL; 
END myProcedure; 
/