An XML metadata schema in metadata101 consists of:

  1. The XML schema documents describing the structure of a metadata record — see Schema.
  2. Human-readable names and descriptions of the elements in a metadata record — see Help.
  3. Codelists and thesauri for those elements of a metadata record that have a controlled vocabulary - see Codelists And Thesauri.
  4. Schematron rules for validating metadata records — see Schematron.
  5. XML Stylesheet Language (XSL) transformers that can be used to convert records to other metadata schemas — see Convert.
  6. Sample metadata records (optional) — see Sample Data.

This information, along with an identifier, name, and description for the metadata schema, is described in an XML file called ident.xml.

An example metadata101 schema is the Marine Community Profile of ISO19115/19139, which can be found here.

What is the difference between a metadata schema and a metadata profile?

A metadata schema is an implementation of a metadata standard. It describes the elements of the standard, how they can be used in a metadata record, and how the metadata record can be validated to ensure that both the structure and the content are correct.

A metadata profile is a community version of a metadata standard — it may subset or extend a metadata standard and should describe how to use a metadata standard in a particular community.
For example, MCP is the Marine Community version of the ISO19115 metadata standard; it is a superset (adds elements to the base standard) and describes how the ISO19115 (and extension) elements should be used by the members of the community.