Creating and updating metadata nodes

To create a new metadata node, create an instance of the appropriate Python class, then use the save() method, e.g.:

from fairgraph.openminds.core import SoftwareVersion

sv = SoftwareVersion(
    name="numpy",
    alias="numpy",
    version_identifier="1.14.9"
)
sv.save(client, space="myspace")

To update a node, edit the attributes of the corresponding Python object, then save() again:

from fairgraph import IRI

sv.homepage = IRI("https://numpy.org")
sv.save(client)

(Note that for updating existing objects you don’t need to specify the space.)

How does fairgraph distinguish between creating a new node and modifying an existing one?

If a previously-created node has been retrieved from the Knowledge Graph, it will have a unique ID, and therefore calling save() will update the node with this ID.

If a new Python object is created with the same or similar metadata, fairgraph queries for a node with matching metadata for a subset of the properties. If you want to know which properties are included in the match, examine the existence_query_properties attribute, e.g.:

>>> SoftwareVersion.existence_query_properties
('short_name', 'version_identifier')

Saving child nodes

By default, fairgraph will recursively save all child objects of the object that is being directly saved. For example, if saving a Dataset it will also save all the Person objects in the authors property.

To turn off this recursive behaviour (for example, because you know the child objects have not been modified, or because you want more fine-grained control over what gets saved), run:

>>> obj.save(client, space="myspace", recursive=False)

Permissions

If you get an error message when trying to create or update a node, it may be because you do not have the necessary permissions. See Access permissions for more information.