有关oracle Blob

[color=cyan]我 insert into eps_cp_attach(attachid, attachname, attachsize, attachcontent, attachtype, attachcreatetime,cpid)values (seq_eps_attach.nextval, :attachname, :attachsize, :attachcontent, :attachtype, :attachcreatetime,:cpId)
ok,数据插入成功？其中attachcontent数据库中式blob类型，对应实体是byte[] 但是当我用：merge into eps_cp_attach a using(select count (*) cnt from eps_cp_attach b where  b.cpid=:cpId and b.attachtype = :attachtype ) N on (N.cnt <> 0) when not matched then insert (attachid, attachname, attachsize, attachcontent, attachtype, attachcreatetime,cpid) values (seq_eps_attach.nextval, :attachname, :attachsize, :attachcontent, :attachtype, sysdate,:cpId)当时，总是报无法从套接字读取更多的数据。各位大侠知道什么原因吗？有关oracle blob的详细用法请留言告知，谢谢！[/color]