christian_dindin(石之轩),请进。求直接从SQLSERVER数据库中提取和保存华表数据的方法

[mengli1]

你好，我看到了你在华表论坛上的留言。言中提到了直接从数据库中提取和保存华表数据。我用PB实现了该功能，但在DELPHI中却不知道如何去做。
我用的是delphi5.0和华表4.2和sqlserver2000的版本，请告诉我如何去做好吗？我很着急，请最好告诉我相关源码。

[一点点凋落]

假设数据库中有表test,两个字段id和image,id是主键
Cell1是要保存的Cell，Cell2用来显示从数据库提取出来的Cell
把query1的requestlive设置为true
保存：
procedure TForm1.Button1Click(Sender: TObject);
var
temp: TBlobStream;
MStream: TMemoryStream;
begin
Query1.Close;
Query1.SQL.Text:='select * from test';
Query1.Open;
Query1.Insert;
Query1.FieldByName('id').AsInteger:=1;
temp:=TBlobStream.Create(TBlobField(Query1.FieldByName('image')),bmWrite);
MStream:=TMemoryStream.Create;
Cell1.DoSaveFile('d:\ss.dat');
MStream.LoadFromFile('d:\ss.dat');
MStream.SaveToStream(temp);
Query1.Post;
end;

提取
procedure TForm1.Button2Click(Sender: TObject);
var
temp: TBlobStream;
MStream: TMemoryStream;
begin
Query1.Close;
Query1.SQL.Text:='select * from test where id=1';
Query1.Open;
Query1.Edit;
temp:=TBlobStream.Create(TBlobField(Query1.FieldByName('image')),bmRead);
MStream:=TMemoryStream.Create;
MStream.LoadFromStream(temp);
MStream.SaveToFile('d:\ss2.dat');
Cell2.DoOpenFile('d:\ss2.dat');
end;

Delphi5+SQL Server7.0通过。

[mengli1]

可我要求是不通过临时文件转换，直接从数据库中提取和保存华表数据。现在华表4.2版本有个SaveToBuffer\ReadFromBuffer来保存和读入华表文件到olevariant型变量。
我想要的是如何将olevariant写入和读出到sqlserver

[一点点凋落]

试了一下：

procedure TForm1.Button1Click(Sender: TObject);
var
temp: TBlobStream;
V: OleVariant;
MStream: TMemoryStream;
Size: Integer;
Buffer: Pointer;
begin
Query1.Close;
Query1.SQL.Text:='select * from test';
Query1.Open;
Query1.Insert;
Query1.FieldByName('id').AsInteger:=1;
temp:=TBlobStream.Create(TBlobField(Query1.FieldByName('image')),bmWrite);
MStream:=TMemoryStream.Create;
try
Cell1.DoSaveToBuffer(V);
Size:=VarArrayHighBound(V,1)-VarArrayLowBound(V,1)+1;
Buffer:=VarArrayLock(V);
MStream.WriteBuffer(Buffer^,Size);
VarArrayUnLock(V);
MStream.SaveToStream(temp);
Query1.Post;
finally
MStream.Free;
temp.Free;
end;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
temp: TBlobStream;
MStream: TMemoryStream;
Buffer: Pointer;
V: OleVariant;
begin
Query1.Close;
Query1.SQL.Text:='select * from test where id=1';
Query1.Open;
Query1.Edit;
temp:=TBlobStream.Create(TBlobField(Query1.FieldByName('image')),bmRead);
MStream:=TMemoryStream.Create;
try
MStream.LoadFromStream(temp);
V:=VarArrayCreate([0,MStream.Size-1],varByte);
Buffer:=VarArrayLock(V);
MStream.ReadBuffer(Buffer^,MStream.Size);
VarArrayUnLock(V);
finally
MStream.Free;
temp.Free;
end;
Cell2.DoReadFromBuffer(V);
end;