[Firebird-net-provider] "sealed" class - what a idea it was ?

[Jakub Czyżkowski]

Hello,  I am new on this group, so "Hello to Everybody" :-) I get a new task: To make a data-access layer for new framework for Windows Form Appliactions (ERP class) under .NET Framevork (and CF too). Of cource, the main database that my company use is Firebird. So I started reading books about .NET, ADO.NET and I'am a litte confused. That is my problem: Our users are used to use large data-tables as they are, et. in one grid viewing 2000 clients. In our present application, based on VCL and DAtaSet-architecture, we ware using TgbDataSet-descendant to "symulate" accessing to large table, holding in memory cache only few records, that are neccessary. TgbDataSet (http://devrace.com/en/fibplus/download/19-43.php) used a couple of SQL-commands to acces diferent parts of data-pockets. When user/control called "Find" method on DataSet, there was a special query generated, if record was found (on serwer), next query for down-record was called and upper-records was called. Maybe there was a couple of queries, but only few record was "downloaded" from serwer, but user (and application developer) has the feeleing to work with all record (you known, PgUp, End, Home, Last(), First(), etc. - it much easier for application developer running like that). Of course, for small data-sets, it works like orignal IBX or FIB. Now I must do something like that under ADO.NET. I was thinking, that I'll create FbDataAdapter, DataTable and DataView descendants, wchich could work-together to achieve that effect. I can not use standard DataAdapter.Fill() method for "oryginal" sql, which is passed into data-layer by application develoer. Yesterday I discovered - almost all classes in Firebird .NET Provider are sealed !! So I can not make descendant of this class, what would be very simple and helpfull. Now I don't have any other idea as writing my own MyFbDataAdapter, copying code from Firebird .NET Provider. Can I do that ? (I mean licensing rights) Or maybe there is another idea, how can I realize my goal ? Best regards   Qubeczek