Descriptor Model
- Creighton Barrett
Definition
A model that defines the mandatory and optional attributes needed for a Collection Descriptor or a Transfer Object Type Descriptor.
Introduction
PAIS uses the term ‘Descriptor’ for a Transfer Object Type Descriptor or a Collection Descriptor, and the phrase ‘Transfer Object’ refers to an instance. The phrase ‘Transfer Object Type’ or ‘type of Data Object’ is used to refer to the class of a Transfer Object or Data Object.
PAIS 2.2 explains that:
One of the objectives of the Formal Definition Phase is to define the Data Objects, where hereafter a Data Object is understood to be one or more data files, to be transferred as possibly more complex data structures called Transfer Objects. Each Transfer Object is an instance of a particular Transfer Object Type. Each Transfer Object Type is described in detail by a Transfer Object Type Descriptor. A Transfer Object Type Descriptor consists of a set of mandatory, optional, and possibly user-defined attributes, and is generated for each type of Transfer Object. A collection of Transfer Object Types, or a collection of other collections, is described by a Collection Descriptor. It also consists of a set of mandatory, optional, and possibly user defined attributes….The set of Descriptors for a Producer-Archive Project constitutes a Model called the Model of Objects for Transfer (MOT) for that project.
Each Descriptor must be associated with a Descriptor Model that defines the mandatory and optional attributes needed to describe types of Transfer Object (the Transfer Object Type Descriptor Model) and Collections (the Collection Descriptor Model).
PAIS Descriptor Model Specifications
Section 3 of PAIS provides specifications:
Model for the Transfer Object Type Descriptor (CCSD0014)
Model for the Collection Descriptor (CCSD0015)
Dalhousie Libraries Descriptor Models
The Dalhousie Libraries has defined a set of Descriptor Models:
Collection Descriptor Models
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