Schema files are created in the XML language. The language consists of elements (tags) with nesting rules and of attributes with permitted value assignments. These are described in the following sections.
Each tag is enclosed in angle brackets < >. There must be an opening tag, for example <mapping> and a closing tag, for example </mapping>, except for elements that do not enclose content or a sub-element. For elements without content, i.e. without sub-elements, the opening tag also functions as the closing tag, for example <key/>.
Attributes control the appearance and behavior of the element. They are listed within the tag, for example <key type="String" value="Length"/>.
The rules of nesting are stored in the schema file. This determines the hierarchy of the elements and which sub-elements are allowed for an element.