create directory

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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 exp_dir as '/tmp';

目录创建以后，就可以把读写权限授予特定用户，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 oneeygle test write twoPL/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 droppedSQL> select * from dba_directories;OWNER                          DIRECTORY_NAME                 DIRECTORY_PATH------------------------------ ------------------------------ ------------------------------SYS                            UTL_FILE_DIR                   /opt/oracle/utl_fileSYS                            BDUMP_DIR                      /opt/oracle/admin/conner/bdump