To discuss one question: how can we implement SharePoint in complicated business processes?

You can directly use the list and other functions in Moss for general services.

However, for complex business processes, such as large data volumes, the use of lists may have performance problems.

I would like to ask, how do we deal with this situation?
Add a database table in sqlserver by yourself?
How can I display and maintain a table on the front end after adding it? Is BDC and infopath used?
For example, if you want to jump to the modification page from the overview page, how do you jump to and add your own page in SharePoint?

I have not actually done any projects in this area. In the past, most of them were page customization classes. I would like to ask you how to deal with them in actual development. Thank you !!