Sams Teach Yourself XML in 10 Minutes

What Is an Entity?

An entity is an expression of the physical, rather than logical, structure of an XML document. An entity is a physical data object. When your XML documents are short and simple, you likely will seldom use entities other than the built-in entities. As you begin to create XML documents of greater length and complexity, the usefulness of entities will become more apparent.

One situation in which entities are sometimes used in relatively short documents is in Scalable Vector Graphics (SVG), an XML application language that you will meet in Chapter 15, “Presenting XML Graphically—SVG.” In SVG, for example, an entity can be used to define a particular style. If you had an entity called BlackAndRed, you could declare it like this: ...