Many discipline-specific and community-specific metadata standards have evolved to meet the challenge of supporting data management and discovery as well as capturing and communicating information to users. Islandora’s system is based on an understanding that the complexity of content-types and metadata standards, and the scarcity of metadata creation, management, and validation tools pose barriers to effective information management.
The The following chapter will outline the role of descriptive metadata in the Islandora system. If you are using Islandora, it is presumed you have a strong understanding of metadata standards that you will be working with, and the role of descriptive metadata in organizing information assets.
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Islandora also preserves the use of Fedora’s underlying administrative metadata (such as audit streams that indicate what has happened to an object and when) and relationship metadata (codified in the RELS-EXT streams of objects). Some Islandora Solution Packs also utilize the EXIFtool to extract technical metadata from objects and store it in a separate datastream. |
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Islandora utilizes Fedora’s ability to represent Descriptive metadata in XML format via one or more Datastreams in an object. Fedora is written in such a way that any object may have multiple metadata Datastreams, which can store Metadata following any schema, such as MODS, Dublin Core, or QDC.
Metadata is added to When an object is created in Islandora via an ingest form presented to users adding objects to the repositor, this ingest form produces an XML metadata datastream when the object is ingested. Each metadata stream will have a default DSID. Users fill out a form with fields corresponding to the metadata desired, and the relevant Datastream is created when the object in Fedora is created. The Datastreams that Islandora creates are defined in the Content Model Object that is affiliated with the Collection into which an item is being ingested. The Content Model prescribes, among other things, the DSID of a datastream containing metadata that can be viewed and edited via Islandora. Islandora’s Solution Packs come with a Content Model which is ingested into your repository when the Solution Pack is installed, and which prescribes the type of metadata that will be collected on ingest, and in what Datastream that metadata will be stored. Users enter metadata via a Form that is defined in a Content Model. Solution Packs come with a set of forms pre-installed. These forms are based on our understanding of best practices, and represent a starting point for those new to the process of creating XML forms., a datastream containing Dublin Core XML metadata is automatically produced and is given "DC" as its DSID, but you will most likely want a separate datastream containing metadata from a richer metadata schema.
To accommodate the richer metadata, each Islandora Solution Pack comes with a pre-installed metadata form that can be used as a starting point in building your own rich metadata form. So, a user ingesting a new object is presented with the metadata form appropriate for that collection. The Content Model for the collection specifies the DSID of that metadata datastream in order to maintain consistency across all objects associated with that Content Model.
The form that come pre-installed with a Solution Pack represent just a starting point to help you create an XML form appropriate for your data. You can leave the form as is or modify it to meet the needs of your repository.
XML Metadata The system is designed to simplify the process of creating metadata for an object. One Islandora content model may have a number of forms to suit the needs of different collections. Forms can be edited, created, copied, and affiliated with Content Model objects using the Islandora Form Builder (XML Forms Modules). When you use the Form Builder, an .xsd in the Form Builder Modules can read in an externally or internally stored schema (another .xsd document), and allow for a form to be created and validated based on that external schema. Users can then associate the newly created or edited form with other content models in the repository via the User Interface (providing that they associate the form with a content model that prescribes that scheme, and permits an XML datastream corresponding to it). Likewise, one Islandora content model may be associated with a number of forms to suit the needs of different collections.In order to fully utilize the Forms Builder, users will have to have an understanding of XML, Schema documents, and Xpath XPath (the language used to navigate XML documents).
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This means that Islandora’s Solution Pack Content Models come with define a Datastream defined that allows for additional granularity and is customized to the needs of a particular data type or subject area. This also means that the Solution Packs come with a form that presents users with a richer metadata schema than Dublin Core. When metadata is created using the this ingest form, an .xslt is called by the Content model. This .xslt file Model to transforms the richer metadata schema into the default Dublin Core datastream, and stores both the richer XML based Descriptive Metadata and the Dublin Core Metadatain Metadata in the object. In this way, Islandora preserves a common metadata stream (in Dublin Core format) that can be useful for searching and retrieving metadata objects across the repository, as well as a more granular metadata stream, say, MODS or Darwin Core, that describes the object as is most appropriate for the subject area or discipline to which the object refersrelates. When Whenever a metadata field is updated through the Islandora interface, the .xslt is called to perform the transformation again, making sure that the Dublin Core datastream is kept consistent with the data in the richer Metadata Datastream.
In the end, the architecture surrounding descriptive metadata in Islandora is designed to provide out-of-the box metadata creation, but also customization. New forms can be created and affiliated associated with Content Models via the Islandora interface. Content Models can be written to define any number of metadata datastreams, and to call .xslt files to create new datastreams on ingest, and to update datastreams when metadata is edited. The system leverages the external community by taking advantage of .xslts that are commonly produced to serve similar use-cases for other organizations.
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