Chapter 5: Realizing a Metadata Framework 163 times. For example, a value “0+” means that the attribute can be given zero or more times, meaning it is an optional attribute. If an attribute is optional but it exists once and only once, it is indicated with the notation “0,1”. 5.6.6 The Most Typical Metadata Schema Objects and Attributes OBJECT Attribute Type N Comment ID UUID 1 Unique ID. Provided by the framework. accessPath String 1+ Path (URL) to the object. This is not a fi eld but part of the object id. creationDate Date 1 Date and time when the object was created. lastModifi edDate Date 0,1 Date and time when the object was last modifi ed. Title String 1 Human-readable title of the object. Size Integer 1 Size of the object in bytes. Description String 0+ Freetext description from the object creator. Freetext String 0+ This is not an actual metadata fi eld but handled by the freetext indexing engine. Each object may have freetext that is effi ciently indexed by the engine, e.g., effi cient retrieval Comment String 0+ A fi eld for some free-form comments. CONTENT OBJECT Attribute Type N Comment Rating Integer 0,1 User-given quality rating of the content object. Counter Integer 0,1 Rendering count of the object. Genre String 0+ Genre of the object. Drm Boolean 0,1 Flag to indicate protected content. releaseDate Date 0,1 The date when the content was released to public. mediaFormat String 0,1 RFC 2046 media type.