Metadata Types and Schemas
Further Information
Types of metadata
In the context of repositories, there are three main types of metadata:
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Descriptive: Facilitates resource discovery and identification; includes elements such as item titles, authors and keywords
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Structural: Describes how items relate to one another; particularly important for recording versions of an item over time and for dealing with complex items such as chapters within a book or learning packages
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Administrative: Helps manage the resource itself; it includes rights management and preservation metadata that records how files were created and the rights associated with them
Defining your metadata schema
Metadata schemas are sets of metadata elements designed for a specific purpose, such as describing a particular type of information resource. Most schemas will cover all three types of metadata identified above. Repository administrators will need to consider their metadata schemas at an early stage of repository implementation. The schemas being used will vary depending on the types of content being stored, the repository's audience, and the intended use of the repository contents. An institutional repository manager is likely to need to define schemas for everything from the relatively simply text-based materials being received through to more complex multimedia objects. Specialist collections within the repository may benefit from support for a more detailed subject classification.
When defining your schema it is important to consider local needs such as departmental and research structures and any local decisions needed about subject fields. Most people will also need to extend their schemas to new types of materials as the repository grows. Local metadata schemas are often based around one or more agreed metadata standards and may conform to common application profiles. Realistically and in the first instance most people will work with the metadata scheme which comes with the out of the box installation of their chosen software, for example, out-of-the-box DSpace uses. The default scheme should be carefully checked to ensure it meets and complies with basic requirements. Extra fields can be added and schemas customised over time but any change may involve retrospectitve editting of existing records and there is a need to retain the mapping to the export standards to aid interoperability and integration.
