一个三层结构的问题，请各位高手帮帮忙？？？(50分)

我用SocketConnection作三层的客户端连接，由于客户端的数据要提交更新到服务端，只能一个DatasetProvider对应一个Clientdataset，有没有什么办法将一个DatasetProvider对应多个Clientdataset，或者直接在服务端定义函数用于返回客户的数据集，再将数据更新到服务端。。。各位帮帮忙。帮我解决这个问题，谢谢了。。。请给我一些这方面的代码或建议！谢谢了。。。。

运行时设置Clientdataset的ProviderName

一个DatasetProvider对应多个Clientdataset
你可以设置Clientdataset.ProviderName:= 你的服务提供者名称.
动态的修改这个值即可.

在应用层的数据模块中多建几个DatasetProvider就可以了。

写函数返回值为datasetprovide.data就可以实现一对多了

同意楼上的，写个变量把datasetprovide.data返回来给Clientdataset.data就直接OK了

是的,用函数传回DatasetProvider.Data,然后赋值给ClientDataset.Data就可以了.
更新的时候把Clientdataset.Delta传到服务器端,利用DatasetProvider.ApplyUpdate方法向数据提交更新数据.

我后面有类似DSP“池”的说明及源码。你可以参考。

procedure TRDMCardServer.SelectData(const sSQL: WideString;
out pPrvName: WideString);
safecall;
var
ADOTemp: TADODataSet;
i_iCount, i_iTag: Integer;
begin
ADOTemp := ADODS40;
i_iTag := 0;
with frmServerdo
begin
if GetDBConnectionState <> 0 then
Exit;
end;

for i_iCount := 1 to pDSCountdo
begin
ADOTemp := TADODataSet(FindComponent('ADODS' + IntToStr(i_iCount)));
if ADOTemp.Active then
begin
Continue;
end
else
begin
i_iTag := i_iCount;
Break;
end;
end;

if i_iTag = 0 then
Exit;
with ADOTempdo
begin
CommandText := sSQL;
try
Open;
pPrvName := 'DSP' + Trim(IntToStr(i_iTag));
except
pPrvName := '';
Close;
end;
end;
end;

procedure TRDMCardServer.ExecuteData(const sSQL: WideString;
out pResult: WideString;
out pMsg: WideString);
safecall;
safecall;
var
ADOComm: TADOCommand;
begin
Inc(i_CMDOrder);
if i_CMDOrder = 20 then
i_CMDOrder := 1;
ADOComm := TADOCommand(FindComponent('ADOComm' + IntToStr(i_CMDOrder)));
with frmServerdo
begin
if GetDBConnectionState <> 0 then
Exit;
end;

try
ADOComm.CommandText := sSQL;
ADOComm.Execute;
pResult := '1';
pMsg := '数据提交成功！';
except
pResult := '0';
pMsg := '数据提交失败,请检查错误后重新提交！';
end;
end;

客户端调用如下：
type TRDMDataSet = class(TPersistent)
//封装之后的持久层方法调用：
private
IDLLDataPer: IDLLDataPersistent;
DCOMConn: TDCOMConnection;
SocketConn: TSocketConnection;
Adapter: TDAOAdapter;
tmpCDS: TClientDataSet;
published
function begin
Trans(out pMsg: WideString): Boolean;
safecall;
function CommitTrans(out pMsg: WideString): Boolean;
safecall;
function RollBackTrans(out pMsg: WideString): Boolean;
safecall;
procedure CloseClientDS(var DataSet: TClientDataSet);
safecall;
Procedure CloseRDMDS(var DataSet: TClientDataSet);
safecall;
public
function GetMaxCount(const obj: TDataTransferObject): Integer;
overload;
safecall;
function GetMaxCount(const obj: TDataTransferObject;
filtrateSQL: String): Integer;
overload;
safecall;
function SelectRDMDS(const SqlStr: WideString;
var DataSet: TClientDataSet): Boolean;
overload;
safecall;
function SelectRDMDS(const obj: TDataTransferObject;
var DataSet: TClientDataSet): Boolean;
overload;
safecall;
function SelectRDMDS(const obj: TDataTransferObject;
filtrateSQL: String;
var DataSet: TClientDataSet): Boolean;
overload;
safecall;

function InsertRDMDS(const SqlStr: WideString;
out pMsg: WideString): Boolean;
overload;
safecall;
function InsertRDMDS(const obj: TDataTransferObject;
var DataSet: TClientDataSet;
out pMsg: WideString): Boolean;
overload;
safecall;
function InsertRDMDS(const obj: TDataTransferObject;
out pMsg: WideString): Boolean;
overload;
safecall;
function UpdateRDMDS(const SqlStr: WideString;
out pMsg: WideString): Boolean;
overload;
safecall;
function UpdateRDMDS(const obj: TDataTransferObject;
var DataSet: TClientDataSet;
out pMsg: WideString): Boolean;
overload;
safecall;
function UpdateRDMDS(const obj: TDataTransferObject;
out pMsg: WideString): Boolean;
overload;
safecall;

function DeleteRDMDS(const SqlStr: WideString;
out pMsg: WideString): Boolean;
overload;
safecall;
function DeleteRDMDS(const obj: TDataTransferObject;
var DataSet: TClientDataSet;
out pMsg: WideString): Boolean;
overload;
safecall;
function DeleteRDMDS(const obj: TDataTransferObject;
out pMsg: WideString): Boolean;
overload;
safecall;

constructor Create(pDCOMConn: TDCOMConnection);
overload;
constructor Create(pSocketConn: TSocketConnection);
overload;
end;

function TRDMDataSet.SelectRDMDS(const obj: TDataTransferObject;
filtrateSQL: String;
var DataSet: TClientDataSet): Boolean;
safecall;
var
i, j: integer;
begin
Result := SelectRDMDS(Adapter.getSearchSQLString(obj)+filtrateSQL, DataSet);
CloseRDMDS(DataSet);
for i:=0 to DataSet.FieldCount-1do
DataSet.Fields.DisplayLabel := obj.GridInfo;
for i:=0 to obj.GridVisible.Count-1do
begin
for j:=0 to DataSet.FieldCount-1do
if UpperCase(Trim(DataSet.Fields[j].FieldName))= UpperCase(Trim(obj.GridVisible.Strings)) then
DataSet.Fields[j].Visible := false;
end;

end;

function TRDMDataSet.SelectRDMDS(const obj: TDataTransferObject;
var DataSet: TClientDataSet): Boolean;
safecall;
var
i, j: integer;
begin
Result := SelectRDMDS(Adapter.getSearchSQLString(obj), DataSet);
CloseRDMDS(DataSet);
for i:=0 to DataSet.FieldCount-1do
DataSet.Fields.DisplayLabel := obj.GridInfo;
for i:=0 to obj.GridVisible.Count-1do
begin
for j:=0 to DataSet.FieldCount-1do
if UpperCase(Trim(DataSet.Fields[j].FieldName))= UpperCase(Trim(obj.GridVisible.Strings)) then
DataSet.Fields[j].Visible := false;
end;
end;

function TRDMDataSet.SelectRDMDS(const SqlStr: WideString;
var DataSet: TClientDataSet): Boolean;
var
sPrvName: WideString;
begin
Result := False;
sPrvName := '';
DataSet.Close;
DataSet.RemoteServer := SocketConn;

try
if IDLLDataPer.SelectData(@SqlStr, sPrvName) then
begin
DataSet.ProviderName := sPrvName;
try
DataSet.Close;

DataSet.Open;
Result := true;
except
Result := false;
end;
end
else
begin

if IDLLDataPer.SelectData(@SqlStr, sPrvName) then
begin
DataSet.ProviderName := sPrvName;
try
DataSet.Close;
DataSet.Open;
Result := true;
except
Result := false;
end;
end;
end;
except
Raise;
end;

if Copy(Trim(sPrvName),1,3) = 'DSP' then
CloseRDMDS(DataSet);
end;

function TRDMDataSet.InsertRDMDS(const SqlStr: WideString;
out pMsg: WideString): Boolean;
begin
Result := IDLLDataPer.InsertDataSet(@SqlStr, pMsg);
end;

function TRDMDataSet.InsertRDMDS(const obj: TDataTransferObject;
out pMsg: WideString): Boolean;
begin
SelectRDMDS(Adapter.getKeySQLString(obj), tmpCDS);
//主键更新失败
if tmpCDS.Fields[0].Value>0 then
begin
pMsg := '主键冲突，插入操作失败！';
exit;
end;

Result := InsertRDMDS(Adapter.getInsertSQLString(obj), pMsg);
end;

function TRDMDataSet.InsertRDMDS(const obj: TDataTransferObject;
var DataSet: TClientDataSet;
out pMsg: WideString): Boolean;
var
i: integer;
tmpPropList: TMPropList;
begin
SelectRDMDS(Adapter.getKeySQLString(obj), tmpCDS);
//主键更新失败
if tmpCDS.Fields[0].Value>0 then
begin
pMsg := '主键冲突，插入操作失败！';
DataSet.Cancel;
exit;
end;

Result := InsertRDMDS(Adapter.getInsertSQLString(obj), pMsg);
if Result = false then
begin
pMsg := '异常数据，插入操作失败！';
DataSet.Cancel;
exit;
end;

tmpPropList := obj.FPropList;
DataSet.Cancel;
DataSet.Append;

for i:=0 to tmpPropList.PropCount-1do
begin
case tmpPropList.Props^.PropType^.Kind of
tkInteger:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetOrdProp(obj, tmpPropList.Props);
tkInt64:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetInt64Prop(obj, tmpPropList.Props);
tkChar, tkLString, tkString:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetStrProp(obj, tmpPropList.Props);
tkSet:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetSetProp(obj, tmpPropList.Props);
tkEnumeration:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetEnumProp(obj, tmpPropList.Props) ;

tkFloat:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetFloatProp(obj, tmpPropList.Props) ;
tkWChar, tkWString:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetWideStrProp(obj, tmpPropList.Props) ;
end;

end;
DataSet.Post;
end;

function TRDMDataSet.UpdateRDMDS(const SqlStr: WideString;
out pMsg: WideString): Boolean;
begin
Result := IDLLDataPer.UpdateDataSet(@SqlStr, pMsg);
end;

function TRDMDataSet.UpdateRDMDS(const obj: TDataTransferObject;
out pMsg: WideString): Boolean;
var
i: integer;
tmpPropList: TMPropList;
begin
SelectRDMDS(Adapter.getKeySQLString(obj), tmpCDS);
//主键更新失败
if not tmpCDS.Fields[0].Value>0 then
begin
pMsg := '主键不能正确定位，更新操作失败！';
exit;
end;

Result := UpdateRDMDS(Adapter.getUpdateSQLString(obj), pMsg);
end;

function TRDMDataSet.UpdateRDMDS(const obj: TDataTransferObject;
var DataSet: TClientDataSet;
out pMsg: WideString): Boolean;
var
i: integer;
tmpPropList: TMPropList;
begin
SelectRDMDS(Adapter.getKeySQLString(obj), tmpCDS);
//主键更新失败
if not tmpCDS.Fields[0].Value>0 then
begin
pMsg := '主键不能正确定位，更新操作失败！';
DataSet.Cancel;
exit;
end;

Result := UpdateRDMDS(Adapter.getUpdateSQLString(obj), pMsg);

if Result = false then
exit;
tmpPropList := obj.FPropList;
if not (DataSet.State in [dsEdit]) then
DataSet.Edit;
for i:=0 to tmpPropList.PropCount-1do
begin
case tmpPropList.Props^.PropType^.Kind of
tkInteger:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetOrdProp(obj, tmpPropList.Props);
tkInt64:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetInt64Prop(obj, tmpPropList.Props);
tkChar, tkLString, tkString:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetStrProp(obj, tmpPropList.Props);
tkSet:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetSetProp(obj, tmpPropList.Props);
tkEnumeration:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetEnumProp(obj, tmpPropList.Props) ;

tkFloat:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetFloatProp(obj, tmpPropList.Props) ;
tkWChar, tkWString:
if Adapter.GetFldName(tmpPropList.PropNames)<>'' then
DataSet.FieldByName(Adapter.GetFldName(tmpPropList.PropNames)).Value := GetWideStrProp(obj, tmpPropList.Props) ;
end;

end;
DataSet.Post;
end;