FireDAC suitable as data-access component in DataSnap server?

Hello Folks!

In Delphi XE3, when FireDAC became available, I tested it as a possible replacement for +dbExpress+ on the app server side (DataSnap server). I discovered that the IProviderSupport methods of +TADDataSet+ implemented the method +PSUpdateRecord+ by opening the query again, positioning itself on the correct record, go into edit mode and apply the change. This is in stark contrast to +TCustomSQLDataSet.PSUpdateRecord+, which just returns False and forces the +TSQLResolver+ to generate the appropriate update 
SQL command in +TSQLResolver.InternalDoUpdate+. Obviously opening the dataset and locating the correct record is an overhead we would like to avoid.

Now looking at Delphi XE5 I am disappointed that TFDDataSet.PSUpdateRecord is still implemented the same way although there are IProviderSupport methods on TFDAdaptedDataSet such as:
* PSGetCommandText,
* PSSetParams &
* PSExecuteStatement

My +TDataSetProvider.ResoveToDataSet+ is set to False but the +TFDQuery+ does its own thing and ignores the setting.

Here is the call stack of my app server:

Datasnap.Provider.TCustomResolver.ApplyUpdates(Variant array of Byte,0,0)
Datasnap.Provider.TBaseProvider.InternalApplyUpdates(Variant array of Byte,0,0)
Datasnap.Provider.TDataSetProvider.InternalApplyUpdates(Variant array of Byte,0,0)
Datasnap.Provider.TCustomProvider.DoApplyUpdates(Variant array of Unknown,0,0,Unassigned)
Datasnap.Provider.TCustomProvider.ApplyUpdates(Variant array of Byte,0,0,Unassigned)
Datasnap.DSServer.TDSProviderDataModuleAdapter.AS_ApplyUpdates('dspEmployee',Variant array of Byte,0,0,$3AB1360)
Datasnap.DSTCPServerTransport.TDSTCPServerTransport.DoOnExecute(TIdContextPeer($3A7EF10) as IIPContext)
:760d33ca kernel32.BaseThreadInitThunk + 0x12
:77c69ed2 ntdll.RtlInitializeExceptionChain + 0x63
:77c69ea5 ntdll.RtlInitializeExceptionChain + 0x36

It would be nice if FireDAC would cooperate better with DataSnap & +TSQLResolver+.

10/15/2013 11:08:55 AM
embarcadero.datasnap 643 articles. 0 followers. Follow

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