XMLtunnisteet

XMLtunnisteet, or XML identifiers, are special attributes within XML documents used to uniquely identify elements or entire documents. The most common type is the `id` attribute. This attribute is designed to hold a value that is unique within the entire XML document. It is often used to create references to specific elements using other attributes, such as `idref` or `ref`, which point to an element's `id`. This mechanism is crucial for establishing relationships between different parts of an XML structure, similar to how primary keys work in databases.

Another important identifier concept in XML is the `ID` datatype defined by the XML Schema language. When an attribute is declared with the `ID` type, XML parsers and validators can verify its uniqueness within the document. This ensures data integrity and allows for more robust processing of XML documents.

Beyond the `id` attribute, other attributes can be used to convey identifying information, although they may not strictly adhere to the definition of a unique identifier in the same way as the `id` attribute. For instance, an attribute like `name` might be used to identify an element conceptually, but its uniqueness is not guaranteed by the XML specification itself. The primary purpose of XMLtunnisteet is to enable unambiguous referencing and manipulation of XML data, facilitating tasks like data validation, cross-referencing, and navigation within complex XML structures.