怎么把大于32767的CLOB或者BLOB写入到文件中

CREATE TABLE image(NAME VARCHAR2(100),DATA BLOB); DECLARE   LOB_LOC  BLOB;   SRC_FILE BFILE;   DST_FILE BLOB;   LGH_FILE BINARY_INTEGER; BEGIN   INSERT INTO IMAGE   VALUES     ('my_1.png', EMPTY_BLOB())   RETURNING DATA INTO LOB_LOC;   SRC_FILE := BFILENAME('DDD', 'my.png');   SELECT DATA INTO DST_FILE FROM IMAGE WHERE NAME = 'my_1.png' FOR UPDATE;   DBMS_LOB.FILEOPEN(SRC_FILE, DBMS_LOB.FILE_READONLY);   LGH_FILE := DBMS_LOB.GETLENGTH(SRC_FILE);   DBMS_LOB.LOADFROMFILE(DST_FILE, SRC_FILE, LGH_FILE);   UPDATE IMAGE SET DATA = DST_FILE WHERE NAME = 'my_1.png';   DBMS_LOB.FILECLOSE(SRC_FILE);   COMMIT; END;