Ask for advice: What the license of multi-tier components should be?

[jixian.yang]

If there are such components for Lazarus and Delphi, what the license should be?
Maybe it is LGPL for Lazarus and commercial License for Delphi user?

[jixian.yang]

I mean something similar with Datasnap(it was called MIDAS before) in delphi.

[CaptBill]

My understanding is that you can use any license you wish. You can build your app/component and sell it if you want with no restrictions from Lazarus. Or you can choose to offer for free if you like. Totally up to you, the developer.

It's a beautiful thing.

[JD]

I mean something similar with Datasnap(it is called MIDAS before) in delphi.

No such middleware components exists for Lazarus/FPC. You'll have to write your own.

On the other hand, you might also want to look at the freeware, Hyperbase http://www.vglib.com/link-4.html. Hyperbase is an alternative implementation of MIDAS.DLL. It supports 100% of MIDAS' featureset. You can use it freely in your applications.

From the README file:

    Overview
    --------
    HyperBase is a dynamic-link library that implements Borland MIDAS III DLL
    (DBCLIENT.DLL and MIDAS.DLL) ClientDataset Redistributables replacement.
    It allows developers to replace original MIDAS libraries and to use MIDAS III
    functionality without purchasing the expensive MIDAS Deployment License for
    multi-tier programs.


    HyperBase implements all COM objects and interfaces exported by DBCLIENT.DLL
    and MIDAS.DLL. It is a drop-in replacement of Borland MIDAS and allows to
    developer to use all components and existing applications without any code
    modifications.

    HyperBase is available in source code.

I've never used it with Lazarus but since it is packaged as a dll, I guess it should work. Good luck.

(accidentally edited by moderator, but hopefully properly restored. I'm sorry - Marcov)

[jixian.yang]

Thanks.

What the MIDAS.DLL do is to be called by TClientDataset. The component stores delta data(the changed data) and sends it to server side.

The similar one is implimented on www.overbyte.be, it is the MidWare. But it is not LGPL and not OS independant.

The RX memory dataset component can record the delta data too and the net components is supposed to send the data.

Maybe the TBufDataset should be used but it does not support Delphi.

[marcov]

I mean something similar with Datasnap(it is called MIDAS before) in delphi.

No such middleware components exists for Lazarus/FPC. You'll have to write your own.

kbmmw works also (components4developers), midware was already named.

[jixian.yang]

kbmmw works also (components4developers), midware was already named.

Both of them are not OS independent.  Seems the author of Midware do not have a plan to other OS.