Metadata Schemas Management
Digital Preservation (DP) Program utilizes customized metadata schemas in the digital repository, Preservica, in order to connect ingested assets with other systems used at the Library. We are storing minimal metadata, essentially the system identifiers, so as to reduce repetitive work, because the existing systems are used to provide descriptive metadata for our collections.
The system identifiers we store in Preservica metadata fragments will assist us to create relationships and connect ingested assets with other databases such as ArchivesSpace, SPEC (NYPL’s collection management system), Sierra, and other identifiers like barcode, division code, etc.
As the metadata schemas are customized, and are updated with time, DP Program keeps track of the schema documents we use in a private GitHub repository, NYPL/prsv-schemas.
Preservica metadata schema documents
There are three types of Preservica metadata schema documents: XML Schemas, XML Transforms and XML Documents. They are used in different ways in the software. Below information presents their different uses and purposes.
XML Schemas
XML Schemas are XSD (XML Schema Definition) files. Preservica allows these XSD Documents to be registered with the system and they can be used to validate both submission and uploaded documents for compliance with the schema.
XML Transforms
XML Transforms are used for presenting metadata fragments on the Preservica User Interface. There are two types of XML Transforms: editor and viewer. Both types of files are XSLT (Extensible Stylesheet Language Transformations) files.
These files are used to convert the format of XML metadata held in Preservica to another XML schema.
XML Documents
XML Documents are valid fragments of XML. There are two types of XML Documents in Preservica: template and indexer. Both types of files are XML files. Template documents can be used within Preservica User Interface to add blocks of additional metadata to an entity (folder or asset). Indexer documents are used to define a custom search indexer for generic metadata. They should fit the Custom Indexer schema.
Schemas management instructions
Digital Preservation program has developed a Python script, get_schemas.py, to download all three types of metadata schema documents from Preservica. The script utilizes Preservica’s Application Programming Interface (API) to receive data.
After getting the documents, DP staff uploads them into a private GitHub repository. This process is run every three months.