I was involved in a SharePoint(WSS) project that was very data centric. The project consisted of more than 500 lists that has very complex relations between them. The client also asked for more than 350 Reports. Don't tell me why did you use SharePoint from the beginning. It was a managerial decision and we already delivered the project after 14 months of pain (this is 6 months overdue to the deadline)
When we first started the project, we didn't know anything about SharePoint development (believe it or not). The management said that they will take the risk. They were very convinced that SharePoint is the optimal solution for anything!!!(well, that proved wrong at the end of the project).
Anyway, we were learning SharePoint while we were developing. Our development were mainly based on SharePoint designer to customize all the AllItems/NewForm/EditForm/DispForm for every list to provide the needed logic/validation that the client asked for (Using JavaScript). We also implemented around 15 Custom Fields (e.g. master-details fields). We also made an event receiver to handle all the adding/updating/deleting... events for all the lists in the site. Plus around 40 ASP.Net user controls.
The main problems that faced us (we worked-around it but sadly in an inefficient way)
1- The Client asked for a search web part in each AllItems.aspx. The search web part should have multiple keys for the client to search with. We did that using Form Web parts using SPD no problem. But the real problem was how to search for a related field that was not in the current list. (So, in such cases we had to save these fields values in our list to be able to search for (crap, I know!!)). You might ask, why didn't you implement ASP.Net user controls for such task? Well, that would require us to forsake the default AllItems web part, and were already customized hundereds of AllItems.aspx pages with alot of customization that would take us a lot of time to reimplement them from the beginnging. Also, even if we used user controls, CAML is very inefficient in retrieving data from multiple related lists!
2- I think you can guess this one, if we've already faced a big time doing search web parts, how on earth will be able to do the 350 reports!!:D But we figured out a work-around (as usual :S) we made an Access DB file with links to all the 500 sharePoint lists, then we implemented a user control that has a report viewer control. This user controls takes an ordinary T-SQL Query to query on the Access DB, the Access DB retrieves the data from the SharePoint DB and pass it back to the user control which views the DataSet on the report viewer.
There are other administration related problems, but I would like to focus on the development here.
So, after I showed you the picture (sorry for the long post). What do you think was the best SharePoint development technique that we should have taken in such a data centric Project, if any?
I heard that some companies doesn't use lists at all in such projects, and builds there own SQL database tables instead of the SharePoint Database. But I can't keep my self from wondering, If I'm making my own DB, and hence implementing my CRUD web parts from scratch (We will also lose the security module benefits provided by SP Lists), what would be the benefits of SharePoint?
Once again I apologize for the long post.