爲什麼我的異常會阻止代碼運行

Question

我是一名實習開發人員，他負責管理其他人的代碼，因此我的大部分工作都將修改其工作。我在Oracle 10g上使用報表生成器。

我有一個公式中的以下設置：

function get_addressFormula return Char is 
begin 
if :payee_ctc_id is not null then 
begin 
select a.address 
     ,a.address2 
     ,a.address3 
     ,g.location 
      ,g.ppostcode 
into :address1 
     ,:address2 
     ,:address3 
     ,:address4 
     ,:postcode 

from ctc_address a 
    ,geo_locations g 

where a.addresstypeid = 1 
and a.costcentreid = :payee_ctc_id 
and g.locationid = a.locationid 
and a.addressid = (select max(i.addressid) 
         from ctc_address i 
      where i.costcentreid = :payee_ctc_id 
      and i.addresstypeid = 1); 

exception 
    when others then 
     return null; 

    while trim(:address1) is null and (trim(:address2) is not null or trim(:address2) is not null or trim(:address4) is not null) 
    loop 
     :address1 := :address2; 
     :address2 := :address3; 
     :address3 := :address4; 
     :address4 := ''; 
    end loop; 

    while trim(:address2) is null and (trim(:address3) is not null or trim(:address4) is not null) 
    loop 
     :address2 := :address3; 
     :address3 := :address4; 
     :address4 := ''; 
    end loop; 

    while trim(:address3) is null and trim(:address4) is not null 
    loop 
     :address3 := :address4; 
     :address4 := ''; 
    end loop; 

end; 
else 
begin 
    <else code> 
end; 
end if; 

return 'y'; 
end; 

這是除了最後else塊完整的功能。我嘗試了no_data_found，但仍然無法正常工作。

@tbone。我不知道該怎麼做。到目前爲止，我用一些Google搜索了一些Google搜索。

Answer 1

見Block structure：

<<label>> (optional) 
DECLARE -- Declarative part (optional) 
    -- Declarations of local types, variables, & subprograms 

BEGIN  -- Executable part (required) 
    -- Statements (which can use items declared in declarative part) 

[EXCEPTION -- Exception-handling part (optional) 
    -- Exception handlers for exceptions (errors) raised in executable part] 
END; 

你需要一個BEGIN/END每個EXCEPTION：

if :payee_id is not null then  
    begin 
     <Select statement which place results into placeholders> 
    exception 
     when NO_DATA_FOUND then 
     return null; 
    end; 
    <code>  
else 
    <else code> 
end if; 

另外要注意的是，使用WHEN OTHERS後面沒有RAISE是一個壞code smell。你不想忽略所有的錯誤，所以要具體。通常你只想捕捉一個NO_DATA_FOUND。