" Separating the view from the model makes the model more robust, because the developer is less likely to "break" the model while reworking the view. Attempting to stitch these two worlds together in a hand coded method without architecture is very common, and results in the model object being polluted with knowledge of the interface, and vice-versa . This makes the code very inflexible and difficult to maintain. For this reason (among others), many programming shops develop the user interface design early in the process of design, and freeze the interface early. The unfortunate side effect of this is that the domain of the problem often isn't clearly understood by the programmers until late in the implementation process. Thus, just at the time that the developers are finally competent to create a good interface, they are kept from changing it. MVC models allow the code to be more flexible later in the development process, allowing for changes that make sense at the time it makes sense to make them. Model Power Boat Event driven In contrast, objects in object oriented programming are composed of methods and data members that attempt to model something from the domain of interest. The best models are fully encapsulated, meaning that they implement every aspect of that real world object of interest to the domain of interest, and that they don't have any extra code that doesn't model the real world. "

" The model is another name for the domain layer. Domain logic adds meaning to raw data e. g. calculating if today is the user's birthday or the totals, taxes and shipping charges for shopping cart items. View: This renders the model into a form suitable for interaction, typically a user interface element. MVC is often seen in web apps: the view is the html page and the code which gathers dynamic data for the page. Controller: This responds to events, typically user actions, and invokes changes on the model (but *not* the view). Model Tug Boat Many applications use a persistent storage mechanism (such as a database) to store data. MVC does not specifically mention this data access layer. "