Metadata Editing by Schema Hussein Suleman University of Cape Town August 2003

The Problem  Metadata comes in various shapes (structures) and flavours (semantics).  User interfaces are necessary for the entry/editing of each type of metadata. How general should the interface be? How general is the metadata? Should the interface be as general as the metadata?

Typical Scenario  Normal assumption: First name, initial(s), Last name  Last names in Español: e.g., Guzman Aranda  First names in Arabic: e.g., Goolam Muhammed  Cultures with no last names: e.g., Indian villages of past  Do we need arbitrary number of first name + arbitrary number of last names?

The Culprits  The OAI+XML Effect: XML and XML Schema allows freedom to model arbitrary structured data. OAI-PMH can provide records created elsewhere.  The WWW Effect: HTML forms are linear sequences of editable fields – metadata is not always linear. HTTP requires client-server interaction for Web- based systems – metadata editing is usually modelled as granular.

The Question  Given a structured representation of the most generic form of a metadata record, can we build a corresponding user interface?

Yes?

The Technology  XML Schema is used to describe metadata formats and provides: Bounds on number of instances for a field (or group of fields). Subfields allowed within a field and structure. Basic type checking e.g., strings and numbers  XML Schema does not provide: Visual interface parameters.

XML Schema Extensions  For the purpose of this project, interface description extensions were created as schema “annotations”: Caption to label the field. Input field type, where it is not obvious. Size of text input boxes.  Example: 40

Dealing with HTTP/HTML  A client-server interaction was modelled as follows: The server generates an HTML page based on schema and existing XML. The client renders the page, obtains input and sends the data to the server. The server validates the data and either accepts it (for further processing) or sends it back with requested changes made or errors marked.

Where to now?  Is schema-based editing feasible? Yes!  Is this incredibly new stuff? Not quite!  Is this a standard approach? Not yet? Why?  Still to do: Separate presentation from structure – i.e. create “XMLEdit” to accompany any schema. Use UIML to describe user interfaces. Investigate multiple modalities of metadata editing based on a single description of metadata – e.g., command-line editing, mobile device editing.

Demo

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