From NSDLWiki
Simple sketch of NSDL model - Core objects and some key relationships
NCore defines an atomistic model composed of a number of typed objects and relationships forming a large, interconnected graph.
NCore Object Types
|
- Agent
- Represents a person, institution, or application
|
|
- Aggregator
- Represents a grouping of objects
|
|
- Metadata
- Represents a series of statements describing some entity (Resource, Agent, or Aggregator)
|
|
- MetadataProvider
- Represents a (potentially named/branded) source of metadata
|
|
- Resource
- Represents a single unit of digital content, such as a PDF document or web page
|
NCore Composite Meta Object Types
|
- Collection
- Represents an NSDL Collection of resources.
|
Anatomy of an NCore Object
Internally, NCore objects contain three read/write types of data:
- Properties
- Literal key/value pairs that describe some aspect of the object itself (e.g its handle, OAI itemId). Applications/users may name and define their own properties on NCore objects.
- Relationships
- Directional, named relationship between two NCore objects. The NCore model provides a set of core relationships and associated semantics, but users and applications may name and define their own relationships as well.
- Datastreams
- Buckets in an NCore object for digital content. NCore distinguishes two primary types of data in datastreams: data stored in the repository itself (managed), and pointers to data existing elsewhere on the web (remote).
