oracle blob 的读写 操作

oracle blob 的读写 操作

-- blob 的读写
CREATE   OR   REPLACE   PROCEDURE  P_IMG_INSERT (v_filename  VARCHAR2 )
IS
  v_bfile BFILE; -- 文件指针
  v_blob BLOB;
  DIR CONSTANT  VARCHAR2 ( 20 ) : =   ' TEST ' ; -- 文件存放DIRECTORY,区分大小写
   V_DEST  NUMBER  : =   1 ;  
    V_LANG  NUMBER  : =   1 ;  

BEGIN
   /**/ /*通过empty_blob()函数将类型为blob的列初始化为空以便以后填充*/
   INSERT   INTO  res_info (res_blob)
   VALUES  (EMPTY_BLOB ())  RETURN  res_blob  INTO  v_blob;

  v_bfile: =  BFILENAME (DIR, v_filename);
 
   IF  (dbms_lob.fileexists(v_bfile) != 0 )  THEN  
    dbms_lob.fileopen(v_bfile,dbms_lob.file_readonly);  -- 打开目标文件
     /**/ /*将文件字数据加载到指定的LOB类型变量*/
    dbms_lob.loadblobfromfile(v_blob,
                                                      v_bfile,
                                                      dbms_lob.getlength(v_bfile),
                                                      V_DEST,
                              V_LANG);
      --  dbms_lob.loadblobfromfile 
    dbms_lob.fileclose(v_bfile); -- 关闭文件
     COMMIT ;
    dbms_output.put_line( ' 已经从 ' || DIR || ' 目录中读取了文件 ' || v_filename || ' 向表中插入 ' );

   ELSE -- 如果文件定位器指向的文件不存在
    dbms_output.put_line( ' 文件没找到 ' );
   END   IF ;
  EXCEPTION  WHEN  OTHERS  THEN
  dbms_output.put_line(SQLERRM);
END ;

说明下:

DBMS_LOB.LOADBLOBFROMFILE (
   dest_lob    IN OUT NOCOPY BLOB,
   src_bfile   IN            BFILE,
   amount      IN            INTEGER,
   dest_offset IN OUT        INTEGER,
   src_offset  IN OUT        INTEGER);

 

Parameter	Description
dest_lob	BLOB locator of the target for the load.
src_bfile	BFILE locator of the source for the load.
amount	Number of bytes to load from the BFILE. You can also use DBMS_LOB.LOBMAXSIZE to load until the end of the BFILE.
dest_offset	(IN) Offset in bytbes in the destination BLOB (origin: 1) for the start of the write. (OUT) New offset in bytes in the destination BLOB right after the end of this write, which is also where the next write should begin.
src_offset	(IN) Offset in bytes in the source BFILE (origin: 1) for the start of the read .(OUT) Offset in bytes in the source BFILE right after the end of this read, which is also where the next read should begin.