The following overview is a refresher of key XML terms and concepts that occur throughout this content. It is provided to ensure the use of familiar XML terminology matches your own, but it is not a substitute for an XML tutorial. If you are unfamiliar with XML, see Develop with XML in OpenEdge.

The Extensible Markup Language (XML) is a data format for structured document interchange on the Web and other networks. It is hardware-architecture neutral and application independent. XML documents are composed of storage units called elements that contain either parsed or unparsed data. Parsed data is made up of characters, some of which form character data, and some of which form markup. Markup encodes a description of a document's storage layout and logical structure.