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How to populate Edge properties?

  • February 27, 2025
  • 1 reply
  • 83 views
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Hi,

I understand that we can define properties on edges, but it isn’t clear from the documentation how these properties are populated. I am trying to implement the following model

And defined the data model using DML as follows
 

How can I add a UserActivity edge with properties start_time and stop_time, that I can read while listing all the activities that a User has performed?

Thank you

Best answer by Arild Eide

Hi ​@Yatish Pitta 

 

The model definition you have provided will create a view UserActvitivy and a corresponding container to hold the edge properties. To populate edges you can use the Python SDK like this:


 

from cognite.client import CogniteClient
import cognite.client.data_classes.data_modeling as dm

client = CogniteClient()


client.data_modeling.instances.apply(
        edges=dm.EdgeApply(
            space=space_name,
            external_id="user_activity001", # external id of the edge you are creating
            type=dm.DirectRelationReference(space=space_name, external_id="User.activity"),  # Required type property
            start_node=dm.DirectRelationReference(space=space_name, external_id="activity001"), # Assuming presence of this activity node
            end_node=dm.DirectRelationReference(space=space_name, external_id="user001"), // Assuming presence of this user nade
            sources=[
                dm.NodeOrEdgeData(
                    # View version for UserActivity is auto created

                    source=dm.ViewId(space=space_name, external_id="UserActivity", version=version),
                    properties={"start_time": "2025-02-28T09:00:00", "stop_time": "2025-02-28T09:01:00"},
                )
            ],
        )
)

Hope this helps.

 

Arild Eide

1 reply

Arild Eide
Seasoned Practitioner
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  • Arild Eide
  • Seasoned Practitioner
  • Answer
  • February 28, 2025

Hi ​@Yatish Pitta 

 

The model definition you have provided will create a view UserActvitivy and a corresponding container to hold the edge properties. To populate edges you can use the Python SDK like this:


 

from cognite.client import CogniteClient
import cognite.client.data_classes.data_modeling as dm

client = CogniteClient()


client.data_modeling.instances.apply(
        edges=dm.EdgeApply(
            space=space_name,
            external_id="user_activity001", # external id of the edge you are creating
            type=dm.DirectRelationReference(space=space_name, external_id="User.activity"),  # Required type property
            start_node=dm.DirectRelationReference(space=space_name, external_id="activity001"), # Assuming presence of this activity node
            end_node=dm.DirectRelationReference(space=space_name, external_id="user001"), // Assuming presence of this user nade
            sources=[
                dm.NodeOrEdgeData(
                    # View version for UserActivity is auto created

                    source=dm.ViewId(space=space_name, external_id="UserActivity", version=version),
                    properties={"start_time": "2025-02-28T09:00:00", "stop_time": "2025-02-28T09:01:00"},
                )
            ],
        )
)

Hope this helps.

 

Arild Eide

Mithila Jayalath
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