Metadata Management
Metadata Management
In gCube, the Metadata Management has been designed to rely on the storage facilities provided by the Storage Management layer and its support to manage primary and secondary relations between Information Objects. The subsystem is called upon to support the management of metadata objects and metadata collections, i.e. supporting their creation, access, storage and removal of objects compliant with one or more metadata format and their efficient search. To implement such functions the internals of the subsystem has been organised according to the following architecture.
Reference Architecture
The functions expected by the Metadata Management subsystem are implemented by two cooperating services: one taking care of the creation and management of Metadata Objects and Metadata Collections (Metadata Manager) and another taking care of the support to metadata object retrieval (XML Indexer) as depicted in Figure 1.
- Metadata Manager – this Service is responsible for managing the incoming requests for changing, accessing and manipulating metadata. It associates metadata with Information Objects, remove associations, returns metadata for a given object and updates associated metadata;
- XML Indexer – this Service is a generic XML Indexer service allowing to query the metadata by resolving arbitrary XQuery and XPath expressions against its managed content. It indexes homogeneous collections of XML data.
The following figure depicts the Metadata Model implemented by the Metadata Management Services:
