dbms_lob.append错误还是我做错了

Question

我创建下面的函数

function lob_replace(p_lob in out clob,p_what in varchar2,p_with in clob) return clob 
    as 
     l_temp_number number; 
     l_temp_number_1 number; 
     l_temp_clob clob; 
     l_return_clob clob; 
     l_temp1_clob clob; 
     l_temp2_clob clob; 
    begin 
       l_temp_number:=dbms_lob.instr(p_lob, p_what); 
       --Create a lob locator 
       DBMS_LOB.createtemporary(l_temp_clob,true); 
       DBMS_LOB.createtemporary(l_temp1_clob,true); 
       DBMS_LOB.createtemporary(l_temp2_clob,true); 

       ---substract and build the LOBs 
       l_temp_number_1:=length(p_lob); 
       l_temp_clob:=dbms_lob.substr(p_lob,l_temp_number-1,1); 
       l_temp1_clob:=dbms_lob.substr(p_lob,l_temp_number_1-l_temp_number+1 ,l_temp_number +length(p_what)); 

       --append three diff lob to one 
       dbms_lob.append(l_temp2_clob,l_temp_clob); 
       dbms_lob.append(l_temp2_clob,p_with); 
       dbms_lob.append(l_temp2_clob,l_temp1_clob); 

       l_return_clob :=l_temp2_clob; 

       --remove the tmp lob 
       DBMS_LOB.freetemporary(l_temp_clob); 
       DBMS_LOB.freetemporary(l_temp1_clob); 
       DBMS_LOB.freetemporary(l_temp2_clob); 

       return l_return_clob; 
    end; 

如果我调用该函数如下

declare 
    temp clob; 
begin 
    temp:='replace this #a#'; 
    temp:=lob_replace(temp,'#a#','with this'); 
end; 

这将抛出错误它会抛出以下错误

ORA-06502: PL/SQL: numeric or value error: invalid LOB locator specified: ORA-22275 
    ORA-06512: at "SYS.DBMS_LOB", line 639 
    ORA-06512: at "LOB_REPLACE", line 24 
    ORA-06512: at line 5 

但是这个wi会不会引发错误

declare 
    temp clob; 
begin 
    temp:='replace this #a# '; 
    temp:=lob_replace(temp,'#a#','with this'); 
end; 

请注意最后的temp:='replace this #a# ';

额外的空间是否有任何人知道这样做的原因？

Answer 1

当您构建l_temp1_clob时，如果有任何要添加的内容，您只能添加剩下的高球。改变你的代码：

l_temp1_clob:=dbms_lob.substr(p_lob,l_temp_number_1-l_temp_number+1 ,l_temp_number +length(p_what)); 

要这样：

if l_temp_number +length(p_what) < l_temp_number_1 
then 
    l_temp1_clob := dbms_lob.substr(p_lob, l_temp_number_1 - l_temp_number - 1 , l_temp_number +length(p_what)); 
end if; 

的逻辑是：如果LOB SUBSTR开始是高球结束前。

此外，dd变量是不是在你的测试呼叫声明：

declare 
    temp clob; 
begin 
    temp:='replace this #a#'; 
    temp:=lob_replace(dd,'#a#','with this'); 
end;