Multi-tier App = UniDAC + EntityDAC + DataSnap ?

[Anachronox]

Hello.

I intend to create new multi-tier database applications using these three data frameworks (UniDAC + EntityDAC + DataSnap), but I'm not sure if this is "ideal" combination of technologies. Please help me decide and discuss the pros and cons or alternatives.

So I need to:
- have clear architecture and simple code (no code/tier duplications, max reuse of objects)
- use ORM whenever it is possible (on the server surely, but if possible on the client too)
- have (default) support for visual data editing, sorting, filtering, etc., via DBGrids
- mid-to-high performance and reliability (LAN/WAN usage)
- transaction durability

- I will NOT use stored procedures and triggers (data changes/requests will be handled only by ORM)
- I will USE autoincrements (identities)

I have standard expertise in UniDAC/SDAC/ODAC and in remoting (RemObjects SDK).

I have NO expertise in ORM and DataSnap (but DataSnap looks more simple then RO SDK). If it will make sense, DataSnap may be altered to RO SDK, but not to DataAbstract (RO SDK is just a pure remoting, but RO DataAbstract is complete remote dataset solution, which I don't want to use since it seems to double some ORM functionality in EntityDAC).

I am a big fan of Devart and RemObjects, but I have no problems using native Delphi technologies (Enterprise edition).

Thank you so much for discussion and tips.

Regards,

Peter.

[Anachronox]

Well,

I've found that RO SDK can be used as a DataSnap "provider" (not only provider - it's more complex since it uses complete RO SDK backend) and it suits to me well.

My basic assumption is that DataSnap uses JSON for data interchange, which I don't like (wasting CPU power for parsing, bigger data packets, etc.). But in RO SDK I can use my favourite binary message format (with minimal overhead).

However, the discussion is still open - I just corrected myself that DataSnap and RO SDK can be used together in the interesting manner.

Thank you.

[AlexP]

Hello,

You can use EntityDAC in a multi-tier/three-tier application either on the server side and on the client side. In the first case EntityDAC will be connected to UniDAC and when you call a method from the server you will work with EntitDAC classes. When using EntityDAC on the client side, the dbExpress DataSnap driver will be used as provider, and all the work and data presentation will be implemented at the level of EntitDAC classes.
In both cases the DataSnap technology from Embarcadero will be used, thus data will transfer in JSON format.

[Anachronox]

Thank you Alex, excellent.

Are there some demos for this purpose? I mean dbExpress DataSnap driver samples for client side with EntityDAC especially.

Thank you.

[AlexP]

At the moment we can provide only "basic" examples that demonstrates the work of EntityDAC. We will consider the possibility to add the demo of EntityDAC and DataSnap after the release of EntityDAC.

[abnerh69]

Hi AlexP,

Sorry to disturb your peace this first days of the year.

I am new with EntityDAC and DevArt components. Your last comment was "consider the possibility to add demo of EntityDAC and DataSanp after the release of EntityDAC"

Please, let me know if there is a demo, or, if there is a way to use TFDJSONDataSetsWriter from FireDAC with EntityTable or EntityQuery components.

Thanks

Abner

[AlexP]

Now, we haven't yet made an EntityDAC and DataSnap demo. You can try yourself using EntityDAC and TFDJSONDataSetsWriter. If you have any additional questions concerning EntityDAC, please contact us.

[ageu]

Hello
I would like to start with EntityDAC + FireDAC + DataSnap.
I am looking for a demo sample application.
Somebody could share a sample project?
Best Regards
Ageu

[AlexP]

No, we have no sample of EntityDAC + FireDAC + DataSnap usage. You can take a sample of FireDAC + DataSnap and add EntityDAC by specifying in EntityConnection the connection string generated in FDConnection.