Functional programming and databases
Eric Lippert made some interesting statements about the disadvantages of functional programming on Stack Overflow: “When Jane Smith in accounting gets married and changes her name to Jane Jones, the database backing the business process that prints her paycheque had better be all about handling that sort of mutation. When you fire the machine gun at the alien, most people do not mentally model that as the construction of a new alien with fewer hit points; they model that as a mutation of an existing alien's properties… My point is that if you have an object that represents an employee, it makes sense to think of the operation "change the name of the employee" to be a mutation of the object representing the employee that does not change object identity. When Jane Smith changes her name you don't create a different employee called Jane Jones that is otherwise the same. There aren't two employees with two different names. It is natural to model this ...