Using Create directory & UTL_FILE in Oracle

作者：eygle  【著作權聲明：轉載時請務必以超連結形式標明文章原始出處和作者資訊及本聲明】
連結：http://www.eygle.com/archives/2005/04/using_create_di.html

Create directory讓我們可以在Oracle資料庫中靈活的對檔案進行讀寫操作，極大的提高了Oracle的易用性和可擴充性。
其文法為:
CREATE [OR REPLACE] DIRECTORY directory AS 'pathname';

本案例具體建立如下:

create or replace directory exp_dir as '/tmp';

目錄建立以後，就可以把讀寫權限授予特定使用者，具體文法如下:
GRANT READ[,WRITE] ON DIRECTORY directory TO username;

例如:

grant read, write on directory exp_dir to eygle;

此時使用者eygle就擁有了對該目錄的讀寫權限。

讓我們看一個簡單的測試:

SQL> create or replace directory UTL_FILE_DIR as '/opt/oracle/utl_file'; Directory created. SQL> declare 2 fhandle utl_file.file_type; 3 begin 4 fhandle := utl_file.fopen('UTL_FILE_DIR', 'example.txt', 'w'); 5 utl_file.put_line(fhandle , 'eygle test write one'); 6 utl_file.put_line(fhandle , 'eygle test write two'); 7 utl_file.fclose(fhandle); 8 end; 9 / PL/SQL procedure successfully completed. SQL> ! [oracle@jumper 9.2.0]$ more /opt/oracle/utl_file/example.txt eygle test write one eygle test write two [oracle@jumper 9.2.0]$

類似的我們可以通過utl_file來讀取檔案:

SQL> declare 2 fhandle utl_file.file_type; 3 fp_buffer varchar2(4000); 4 begin 5 fhandle := utl_file.fopen ('UTL_FILE_DIR','example.txt', 'R'); 6 7 utl_file.get_line (fhandle , fp_buffer ); 8 dbms_output.put_line(fp_buffer ); 9 utl_file.get_line (fhandle , fp_buffer ); 10 dbms_output.put_line(fp_buffer ); 11 utl_file.fclose(fhandle); 12 end; 13 / eygle test write one eygle test write two PL/SQL procedure successfully completed.

可以查詢dba_directories查看所有directory.

SQL> select * from dba_directories; OWNER DIRECTORY_NAME DIRECTORY_PATH ------------------------------ ------------------------------ ------------------------------ SYS UTL_FILE_DIR /opt/oracle/utl_file SYS BDUMP_DIR /opt/oracle/admin/conner/bdump SYS EXP_DIR /opt/oracle/utl_file

可以使用drop directory刪除這些路徑.

SQL> drop directory exp_dir; Directory dropped SQL> select * from dba_directories; OWNER DIRECTORY_NAME DIRECTORY_PATH ------------------------------ ------------------------------ ------------------------------ SYS UTL_FILE_DIR /opt/oracle/utl_file SYS BDUMP_DIR /opt/oracle/admin/conner/bdump