This is impossible to answer. If we take your employees as an example, using one process per employee is likely wrong because it’s hard to argue why you should have one process per employee instead of a single process holding a list of employees. You also want to store schedules, should they be stored separately from employees? Possibly, but what would you gain from that?
Eventually you can consider storing the whole database in one process. What are the benefits and downsides of this? One benefit is less complexity, one process is simpler than multiple, another is that you can more easily implement transactions because you don’t need synchronization between multiple process.
One downside can be seen as an code organization, all your database would be in one location, but this is the misconception. Code is organized with modules, so you can have multiple modules for one process. Another downside can be scalability, you may want to shard your database to multiple process so you can use all your cores. This is when you should start considering using multiple process.
So to summarize, it is hard to answer this question because you are asking how to structure an application using processes when we are saying that you shouldn’t. I would suggest that you start writing the application without processes or with a single process and then when you hit a road block that you think processes will solve come back and ask a question that is specific to your problem and less abstract and hypothetical.
