服务器 频道

使用PL/SQL从数据库中读取BLOB对象

  【IT168 服务器学院】1.确认现有对象
  
  SQL> col fdesc for a30
  SQL> select fid,fname,fdesc from eygle_blob;
  
  FID FNAME                       FDESC
  ---------- -------------------------------------------------- ------------------------------
  1 ShaoLin.jpg                    少林寺-康熙手书
  2 DaoYing.jpg                    倒映
  
  2.创建存储Directory
  
  SQL> connect / as sysdba
  Connected.
  SQL> create or replace directory BLOBDIR as ''D:\oradata\Pic'';
  
  Directory created.
  
  SQL>
  SQL> grant read,write on directory BLOBDIR to eygle;
  
  Grant succeeded.
  
  SQL>
  
  3.创建存储过程
  
  SQL> connect eygle/eygle
  Connected.
  SQL>
  SQL> CREATE OR REPLACE PROCEDURE eygle_dump_blob (piname varchar2,poname varchar2) IS
  2  l_file   UTL_FILE.FILE_TYPE;
  3  l_buffer  RAW(32767);
  4  l_amount  BINARY_INTEGER := 32767;
  5  l_pos    INTEGER := 1;
  6  l_blob   BLOB;
  7  l_blob_len INTEGER;
  8 BEGIN
  9  SELECT FPIC
  10  INTO   l_blob
  11  FROM   eygle_blob
  12  WHERE FNAME = piname;
  13
  14  l_blob_len := DBMS_LOB.GETLENGTH(l_blob);
  15  l_file := UTL_FILE.FOPEN(''BLOBDIR'',poname,''wb'', 32767);
  16
  17  WHILE l_pos < l_blob_len LOOP
  18   DBMS_LOB.READ (l_blob, l_amount, l_pos, l_buffer);
  19   UTL_FILE.PUT_RAW(l_file, l_buffer, TRUE);
  20   l_pos := l_pos + l_amount;
  21  END LOOP;
  22
  23  UTL_FILE.FCLOSE(l_file);
  24
  25 EXCEPTION
  26  WHEN OTHERS THEN
  27   IF UTL_FILE.IS_OPEN(l_file) THEN
  28    UTL_FILE.FCLOSE(l_file);
  29   END IF;
  30   RAISE;
  31 END;
  32 /
  
  Procedure created.
  
  4.取出数据
  
  SQL> host ls -l d:\oradata\Pic
  total 7618
  -rwxrwxrwa  1 gqgai      None      2131553 Apr 19 10:12 DaoYing.jpg
  -rwxrwxrwa  1 gqgai      None      1768198 Apr 19 10:12 ShaoLin.jpg
  
  SQL> exec eygle_dump_blob(''ShaoLin.jpg'',''01.jpg'')
  
  PL/SQL procedure successfully completed.
  
  SQL> host ls -l d:\oradata\Pic
  total 11072
  -rwxrwxrwa  1 Administrators SYSTEM     1768198 Apr 26 07:16 01.jpg
  -rwxrwxrwa  1 gqgai      None      2131553 Apr 19 10:12 DaoYing.jpg
  -rwxrwxrwa  1 gqgai      None      1768198 Apr 19 10:12 ShaoLin.jpg
  
  SQL>
  SQL> exec eygle_dump_blob(''DaoYing.jpg'',''02.jpg'')
  
  PL/SQL procedure successfully completed.
  
  SQL> host ls -l d:\oradata\Pic
  total 15236
  -rwxrwxrwa  1 Administrators SYSTEM     1768198 Apr 26 07:16 01.jpg
  -rwxrwxrwa  1 Administrators SYSTEM     2131553 Apr 26 07:19 02.jpg
  -rwxrwxrwa  1 gqgai      None      2131553 Apr 19 10:12 DaoYing.jpg
  -rwxrwxrwa  1 gqgai      None      1768198 Apr 19 10:12 ShaoLin.jpg
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