[为什么在尝试使用立即执行创建目录对象时出现ORA-00900无效的SQL语句？

Question

我看到在Oracle中有很多这样的例子。只是不适合我。 Oracle11。第15行出现此错误。谢谢大家！

declare 
v_path nvarchar2(256);
v_object_exists number;
begin
    -- Use the directory Oracle DB provide for tracing.
    select VALUE into v_path from V$DIAG_INFO where NAME = 'Diag Trace';
    --dbms_output.put_line(v_path);

    -- Set up new directory!
    select count(*) into v_object_exists from all_objects where object_name = 'DIAG_TRACE' and object_type = 'DIRECTORY';
    if v_object_exists > 0 then 
        execute immediate 'DROP DIRECTORY DIAG_TRACE'; 
    end if;
    dbms_output.put_line('CREATE OR REPLACE DIRECTORY DIAG_TRACE AS ''' || v_path || '''');
    execute immediate 'CREATE OR REPLACE DIRECTORY DIAG_TRACE AS ''' || v_path || '''';

end;

Answer 1

我更喜欢将命令放入变量中，显示它（用于验证），然后执行它：

SQL> declare
  2  v_path nvarchar2(256);
  3  v_object_exists number;
  4  l_str varchar2(200);
  5  begin
  6      -- Use the directory Oracle DB provide for tracing.
  7      select VALUE into v_path from V$DIAG_INFO where NAME = 'Diag Trace';
  8      --dbms_output.put_line(v_path);
  9
 10      -- Set up new directory!
 11      select count(*) into v_object_exists from all_objects where object_name = 'DIAG_TRACE' and object_type = 'DIRECTORY';
 12      if v_object_exists > 0 then
 13          execute immediate 'DROP DIRECTORY DIAG_TRACE';
 14      end if;
 15      l_str := 'CREATE OR REPLACE DIRECTORY DIAG_TRACE AS ' || chr(39) || v_path ||chr(39);
 16      dbms_output.put_line(l_str);
 17      execute immediate l_str;
 18  end;
 19  /
CREATE OR REPLACE DIRECTORY DIAG_TRACE AS
'C:\ORACLEXE\APP\ORACLE\diag\rdbms\xe\xe\trace'

PL/SQL procedure successfully completed.

SQL>

当然，您必须以特权用户（例如SYS）的身份运行它。

Answer 2

好问题。它似乎是一个错误；它不喜欢将pact变量作为execute immediate的一部分串联在一起。您可以使用变量来解决它：

declare
v_stmt varchar2(256);
v_path nvarchar2(256);
v_object_exists number;
begin
    -- Use the directory Oracle DB provide for tracing.
--    select VALUE into v_path from V$DIAG_INFO where NAME = 'Diag Trace';
v_path := '/tmp';
    --dbms_output.put_line(v_path);
    -- Set up new directory!
    select count(*) into v_object_exists from all_objects where object_name = 'XXX' and object_type = 'DIRECTORY';
    if v_object_exists > 0 then
        execute immediate 'DROP DIRECTORY XXX';
    end if;
    v_stmt := 'CREATE OR REPLACE DIRECTORY XXX AS ''' || v_path || '''';
    dbms_output.put_line(v_stmt);
    execute immediate v_stmt;
end;
/

[保存重复的字符串来打印它，尽管您可能只是因为这个问题而这样做了。