All examples are mine and real.
My example 1 (access to tables):
I need that to my employees. They need to open the table with the tasks in the kanban for task status change (new / work / done), but they should not be able to watch and change anything else.
My example 2 (access to fields):
There are employees table. One of the fields - the salary. I need people to have access to the rest of the column, but could not see salary.
My example 3 (access to records):
The design studio has several people on several projects. It is necessary that the people would see only their team projects, suppliers. They should not be visible to others.
My example 4 (access to records):
There is a network of orphanages. Each orphanage has teachers who should only see their children and not have access to other children of orphanages. Each director of an orphanage should have access to their teachers and do not have access to others.
Sorry for my English