如何使用ORACLE中的SQL UPDATE命令将BLOB数据附加/连接到BLOB列

CREATE TABLE my_table (
  id NUMBER PRIMARY KEY,
  blob_data BLOB
);

INSERT INTO my_table (id, blob_data) VALUES (1, UTL_RAW.CAST_TO_RAW('Hello, '));

DECLARE
  v_blob_data BLOB;
BEGIN
  SELECT blob_data INTO v_blob_data FROM my_table WHERE id = 1 FOR UPDATE;
  DBMS_LOB.APPEND(v_blob_data, UTL_RAW.CAST_TO_RAW('World!'));
  UPDATE my_table SET blob_data = v_blob_data WHERE id = 1;
  COMMIT;
END;
/

DECLARE
  v_blob_data1 BLOB;
  v_blob_data2 BLOB;
BEGIN
  SELECT blob_data INTO v_blob_data1 FROM my_table WHERE id = 1;
  v_blob_data2 := UTL_RAW.CAST_TO_RAW('World!');
  DBMS_LOB.CONCATENATE(v_blob_data1, v_blob_data2);
  UPDATE my_table SET blob_data = v_blob_data1 WHERE id = 1;
  COMMIT;
END;
/