Create directory让我们可以在Oracle数据库中灵活的对文件进行读写操作，极大的提高了Oracle的易用性和可扩展性。
其语法为:
CREATE [OR REPLACE] DIRECTORY directory AS 'pathname';
本案例具体创建如下:
create or replace directory exp_dir as '/tmp';
目录创建以后，就可以把读写权限授予特定用户，具体语法如下:
GRANT READ[,WRITE] ON DIRECTORY directory TO username;
例如:
grant read, write on directory exp_dir to eygle;
此时用户eygle就拥有了对该目录的读写权限。
让我们看一个简单的测试:
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 oneeygle test write two[oracle@jumper 9.2.0]$
类似的我们可以通过utl_file来读取文件:
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.
可以查询dba_directories查看所有directory.
SQL> select * from dba_directories;
OWNER DIRECTORY_NAME DIRECTORY_PATH
------------------------------ ------------------------------ ------------------------------
SYS UTL_FILE_DIR /opt/oracle/utl_fileSYS
BDUMP_DIR /opt/oracle/admin/conner/bdumpSYS EXP_DIR /opt/oracle/utl_file
可以使用drop directory删除这些路径.
SQL> drop directory exp_dir;
Directory dropped
SQL> select * from dba_directories;
OWNER DIRECTORY_NAME DIRECTORY_PATH
------------------------------ ------------------------------ ------------------------------
SYS UTL_FILE_DIR /opt/oracle/utl_fileSYS
BDUMP_DIR /opt/oracle/admin/conner/bdump
create or replace directory USER_DIR as 'E:\PLSQL\310\';
DECLARE
v_content VARCHAR2(1800);
v_bfile BFILE;
amount INT;
offset INT :=1;
BEGIN
v_bfile := bfilename('USER_DIR','test.TXT'); -- 注意这里的 User_dir 对应上面已经创建好啦的目录
amount :=DBMS_LOB.getlength(v_bfile);
DBMS_LOB.OPEN(v_bfile);
DBMS_LOB.READ(v_bfile,amount,offset,v_content);
DBMS_LOB.close(v_bfile);
DBMS_OUTPUT.PUT_LINE(v_content);
END;