CQS and CQRS

Command Query Separation The command query separation pattern is an application architecture pattern that separates the logic for queries that don’t update the observable state of a system (i.e. free of side effects) from the logic that performs any state updates to such system (commands). For example, a screen that displays a grid of incidents would have a GetAllIncidents() method, or a GetAllOpenIncidents() in a class IncidentsService, whereas the action to submit Submit() a new incident or update Update() an existing incindent, could be declared in a CreateIncidentCommand class, for example.