Editing Template:EPrints Metadata Fields Content (section)

== Metadata Field Types ==

There are many different types of metadata field. The type controls how a field is rendered, indexed, searched and so forth. A field always has a type and a name property, and usually has several more. Most properties are documented on this page, but some properties are only available to certain types of field, and they are listed on the page for that field. 

Some of these subclasses provide very rich features, others very simple. For example the [[url field]] works just like the text field except that it's only valid if it looks like a url and when rendered it is a hyper-link.

A metadata field describes one field of data in one type of [[Data Object]]. For example the "title" field of an [[EPrint Object]] or the "email" field in a [[User Object]]. 

Every [[Data Object]] has system fields (which are set by the system, and not alterable), but the [[User Object]] and [[EPrint Object]] have additional fields which are configured on a per-repository basis.

These can be customised in the [[user_fields.pl]] and [[eprint_fields.pl]] files. Note that changing these files does not automatically modify the underlying database so should (generally) only be done before the database is created. Some metadata properties do not affect the database, and are marked as such. 

If you add or remove fields, or modify a property which affects the database then you'll need to alter the database to match.  In 3.0 this must be done by hand, but we have plans to build a tool to do this for you.