This guide explains the document hierarchy and the basic data management actions.
The user is always working within the dataspace. A dataspace consists of two LDT applications:
- the end-user application
- the administration application which only administration users have access to
This guide provides the end-user perspective; see Administration guides for the administrator perspective.
The basic structure of resources in an application is analogous to the file system, but built using RDF resources and relationships between them instead. There is a hierarchy of containers (folders), which are collections of items (files) as well as sub-containers (sub-folders). Both containers and items are documents. Items cannot contain other documents.
The first level of resources in a container is referred to as its children (of which that container is the parent, while all levels down the hierarchy are collectively referred to as descendants.
When a user logs in, the application loads its root container (unless a specific URI was requested). From there, users can navigate down the resource hierarchy, starting with children of the root container. At any moment there is only one current document per page, on which actions can be performed: it can be viewed, edited etc.
LinkedDataHub also provides several system containers for built-in content types such as files, imports, and SPARQL queries, as well as temporal and geospatial views over the application's dataset.
The following actions can also be performed using the command line interface.
This is the default action when a document is accessed. The content of the view is different depending on whether the current document is a container or an item. The presentation layout also depends on the current layout mode.
Container view displays a list of its children. Containers usually do not retrieve the full list of their children. Instead, they provide a paginated access over them, allowing a user to navigate between pages that contain a "slice" with a limited number of children.
Item view displays description of the current resource, listing its properties.
Create action creates a new resource of the selected type using create mode. A newly created document becomes a child of the current container, unless a different one is specified in the creation dialog.
Every document can contain (X)HTML content which is edited using an embedded WYSIWYG editor.
The resource type can be something else than a document, e.g. a physical thing such as person, or an abstract concept. In that case, it is referred to as the topic resource which is paired with a document, and they are created together. The relationships between documents and topic resources is managed in the model.
A new document can only be created if it and its topic resource validate, i.e. if all property values from user input satisfy URI syntax, mandatory values and other constraints. Constraints are also managed in the model.
LinkedDataHub stores the description of every document in a separate RDF graph. The distinction between document and its graph is important to understand; it is the graph that is being edited using edit mode and updated as a result of this action.
Just like with document creation, a document can only be updated if it and its topic resource validate, i.e. if all property values from user input satisfy URI syntax, mandatory values and other constraints.
In future versions, we plan to store multiple graphs with descriptions of the same document but with different timestamps, enabling revision history.
This action deletes the current document by deleting the graph with its description.
Deleting a container currently does not delete any of its descendants.
Download action returns the description of the current document as RDF data in the selected format.
Perform an application-wide search for resources (documents as well as their topics) using the search box. Search uses regex to match search keywords against resource labels, descriptions, and content, and shows the results in a dropdown list.
The exact search criteria depend on the query which is configured for the search container in the sitemap.
The search bar also works as address bar for Linked Data resources. Enter a URI and LinkedDataHub will attempt to load RDF data from it by switching into Linked Data browser mode.