clientdataset不能操作blob字段

ffanpeng 2005-08-18 09:30:17

xh（number）
username(varchar2(18))
vvernumber(varchar2(8))
newfile(blob)
只有这四个字段,数据库是oracle
dm.ClientDataSet7.Close;
dm.ClientDataSet7.CommandText:='select * from Yl_xx_userinf';
dm.ClientDataSet7.Open;//到这老报错
数据类型不支持

...全文

201 13 打赏收藏转发到动态举报

写回复

用AI写文章

13 条回复

切换为时间正序

请发表友善的回复…

发表回复

ffanpeng 2005-08-18

打赏
举报

poFetchBlobsOnDemand是不是把这个改成true

ffanpeng 2005-08-18

打赏
举报

to cncharles(旺仔)
poAllowCommandText是不是表示客户端可以重载相关数据集的SQL语句、表的名字或存储过程

cncharles 2005-08-18

打赏
举报

DataProvider中的Opions.poAllowCommandText要为true

ffanpeng 2005-08-18

打赏
举报

我只拿这个处理blob字段

xiaocuo_zrf 2005-08-18

打赏
举报

很多资料都介绍过如果用ADO处理数据会出现各种各样的问题，如果是
Microsoft ADO Driver For Oracle 那么不能处理blob字段
如果是Oracle ADO Driver 那么处理浮点数有问题！
很吐血的。哎。。。。。。。。。

ffanpeng 2005-08-18

打赏
举报

必须用ado要不改得太多了

fjx99 2005-08-18

打赏
举报

你难道是用ADO连接oracle?最好改为ODAC连接，ADO操作oracle有些麻烦

问题：Oracle中对Blob的操作不能像正常的操作，需作如下调整
增加：
Query.Close;
Query.SQL.Clear;
Query.SQL.Add('INSERT INTO myimages(FileName,pic) VALUE(''Image1'',:pic)');
Query.ParamByName('pic').LoadFromFile('D:\Hasd.bmp',ftBlob);
Query.ExecSQL;

修改：
Query.Close;
Query.SQL.Clear;
Query.SQL.Add('UPDATE myimages SET pic=:pic WHERE filename=''Image1''');
Query.ParamByName('pic').LoadFromFile('D:\Hasd2.bmp',ftBlob);
Query.ExecSQL;

ffanpeng 2005-08-18

打赏
举报

问题已经解决，换了一个驱动
但是又有新的问题了
dm.ClientDataSet9.Close;
dm.ClientDataSet9.CommandText:='';
dm.ClientDataSet9.CommandText:='select xh,newfile from yL_XX_userinf';
dm.ClientDataSet9.Open;
dm.ClientDataSet9.Edit;
mystream := TMemoryStream.Create;
mystream.loadfromfile(GetCurrExeDIR+'TCKWJ_YL.exe');
mystream.seek(0,soFromBeginning);
UpdataNewFile.LoadFromStream(myStream);//在这里又出错了不能加载进数据库
dm.ClientDataSet1.FieldByName('VerNumber').asCurrency := (VerServer+0.1);
dm.ClientDataSet1.ApplyRange;

ffanpeng 2005-08-18

打赏
举报

还是数据类型不支持

ffanpeng 2005-08-18

打赏
举报

还是不行

cncharles 2005-08-18

打赏
举报

还有DataProvider中的Opions.poAllowCommandText要为true, 理由如下

By default FetchOnDemand is true, meaning that the client dataset fetches additional packets of data as needed (for example, as a user scrolls through data, or conducts a search). If the provider does not automatically include BLOB fields or nested detail sets in data packets, setting FetchOnDemand to true causes the client dataset to fetch these values when needed as well.

Set FetchOnDemand to false only if your application contains code that explicitly fetches data packets as needed using the GetNextPacket method. Similarly, if FetchOnDemand is false and the provider does not include BLOB data by default (Options includes poFetchBlobsOnDemand), the application must fetch BLOB fields explicitly using the FetchBlobs method. If the provider does not include nested detail sets (Options includes poFetchDetailsOnDemand) and FetchOnDemand is false, the application must fetch nested details explicitly using the FetchDetails method.

cncharles 2005-08-18