Comment by Gracana

My employer was running Growthpower (ERP software) on an HP 3000 system up until 2018 or so. We replaced it with a "modern" .NET/MSSQL ERP solution that does a lot more, but it's slow and terrible to navigate compared to the old console menu system, and its database is hundreds of tables without a single foreign key. The frontend application makes a long series of sequential queries to build each view... if you're willing to wade through the muck, you can write a server side query that can do in milliseconds what it does in minutes.