Posted on 2009-01-10 11:48
詩(shī)特林 閱讀(35237)
評(píng)論(3) 編輯 收藏 所屬分類:
Oracle
Create directory讓我們可以在Oracle數(shù)據(jù)庫(kù)中靈活的對(duì)文件進(jìn)行讀寫操作，極大的提高了Oracle的易用性和可擴(kuò)展性。
其語(yǔ)法為:
CREATE [OR REPLACE] DIRECTORY directory AS 'pathname';
本案例具體創(chuàng)建如下:
create or replace directory exp_dir as '/tmp';
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目錄創(chuàng)建以后，就可以把讀寫權(quán)限授予特定用戶，具體語(yǔ)法如下:
GRANT READ[,WRITE] ON DIRECTORY directory TO username;
例如:
grant read, write on directory exp_dir to eygle;
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此時(shí)用戶eygle就擁有了對(duì)該目錄的讀寫權(quán)限。
讓我們看一個(gè)簡(jiǎn)單的測(cè)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]$
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類似的我們可以通過(guò)utl_file來(lái)讀取文件:
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.
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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
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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
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