Middleware is a framework of hooks into Django’s request/response processing. It’s a light, low-level “plugin” system for globally altering Django’s input and/or output.
Each middleware component is responsible for doing some specific function. For example, Django includes a middleware component, XViewMiddleware, that adds an "X-View" HTTP header to every response to a HEAD request.
This document explains how middleware works, how you activate middleware, and how to write your own middleware. Django ships with some built-in middleware you can use right out of the box; they’re documented in the built-in middleware reference.
File Transfer Protocol (FTP) is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and uses separate control and data connections between the client and the server.[1] FTP users may authenticate themselves using a clear-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission that hides (encrypts) the username and password, and encrypts the content, FTP is often secured with SSL/TLS ("FTPS"). SSH File Transfer Protocol ("SFTP") is sometimes also used instead, but is technologically different. The first FTP client applications were command-line applications developed before operating systems had graphical user interfaces, and are still shipped with most Windows, Unix, and Linux operating systems.[2][3] Dozens of FTP clients and automation utilities have since been developed for desktops, servers, mobile devices, and hardware, and FTP has been incorporated into hundreds of productivity applications, such as Web page editors.
n computing an object-oriented user interface (OOUI) is a type of user interface based on an object-oriented programming metaphor. In an OOUI, the user interacts explicitly with objects that represent entities in the domain that the application is concerned with. Many vector drawing applications, for example, have an OOUI - the objects being lines, circles and canvases. The user may explicitly select an object, alter its properties (such as size or colour), or invoke other actions upon it (such as to move, copy, or re-align it). If a business application has any OOUI, the user may be selecting and/or invoking actions on objects representing entities in the business domain such as customers, products or orders. Jakob Nielsen defines the OOUI in contrast to function-oriented interfaces: "Object-oriented interfaces are sometimes described as turning the application inside-out as compared to function-oriented interfaces. The main focus of the interaction changes to become the users' data and other information objects that are typically represented graphically on the screen as icons or in windows." Dave Collins defines an OOUI as demonstrating three characteristics: Users perceive and act on objects Users can classify objects based on how they behave In the context of what users are trying to do, all the user interface objects fit together into a coherent overall representation. Jef Raskin suggests that the most important characteristic of an OOUI is that it adopts a 'noun-verb', rather than a 'verb-noun' style of interaction, and that this has several advantages in terms of usability.
The bullwhip effect (or whiplash effect) is an observed phenomenon in forecast-driven distribution channels. It refers to a trend of larger and larger swings in inventory in response to changes in demand, as one looks at firms further back in the supply chain for a product. The concept first appeared in Jay Forrester's Industrial Dynamics (1961) and thus it is also known as the Forrester effect. Since the oscillating demand magnification upstream a supply chain is reminiscent of a cracking whip, it became known as the bullwhip.
A logical schema is a data model of a specific problem domain expressed in terms of a particular data management technology. Without being specific to a particular database management product, it is in terms of either relational tables and columns, object-oriented classes, or XML tags. This is as opposed to a conceptual data model, which describes the semantics of an organization without reference to technology, or a physical data model, which describes the particular physical mechanisms used to capture data in a storage medium. The next step in creating a database, after the logical schema is produced, is to create the physical schema.