Assets

In Cognite Data Fusion, the asset resource type stores the digital representations of objects or groups of objects from the physical world. Water pumps, heart rate monitors, machine rooms, and production lines are examples for those assets.

About assets

Assets connect related data from different sources, and are core to identifying all the data that is relevant to an entity (contextualization) in Cognite Data Fusion.

All other resource types, for example time series, events and files, should be connected to at least one asset, and each asset can be connected to many resources and resource types. A pump asset can for example be connected to a time series that measures the pressure within the pump, to events that record maintenance operations, and to a file with a diagram of the pump.

Assets themselves are organized into asset hierarchies. For example, one asset can represent a water pump that is part of a larger subsystem asset on an oil platform asset.

At the top of each asset hierarchy is a root asset (for example an oil platform). Each project can have multiple root assets, and all assets under the root asset must have a parent asset.

TIP

See the assets API documentation for more information about how to work with assets.

Structure an asset hierarchy

This example shows you how to structure the asset hierarchy for the fictional SYSTEM 11:

SYSTEM 11
└───Pump
│   └───Heating cable
└───Pump

Outlined in csv format, the system looks like this:

name	description	externalId	parentExternalId
SYSTEM 11	Sea water system	SYSTEM_11
Pump	Main pump for system 11	PUMP_A	SYSTEM_11
Heating cable	Heating cable for pump A	HEATING_CABLE	PUMP_A
Pump	Backup pump for system 11	PUMP_B	SYSTEM_11

When you structure an asset hierarchy, you can post all assets in one request.

1. Post the following request:

   POST /api/v1/projects/<project>/assets
   Host: api.cognitedata.com

   With this request body:

   {
     "items": [
       {
         "name": "SYSTEM 11",
         "description": "Sea water system",
         "externalId": "SYSTEM_11"
       },
       {
         "name": "Pump",
         "description": "Main pump for system 11",
         "externalId": "PUMP_A",
         "parentExternalId": "SYSTEM_11"
       },
       {
         "name": "Pump",
         "externalId": "Pump_B",
         "description": "Backup pump for system 11",
         "parentExternalId": "SYSTEM_11"
       },
       {
         "name": "Heating cable",
         "externalId": "HEATING_CABLE",
         "description": "Heating cable for pump A",
         "parentExternalId": "PUMP_A"
       }
     ]
   }

   The response body will look similar to this:

   {
     "items": [
       {
         "externalId": "SYSTEM_11",
         "name": "SYSTEM 11",
         "description": "Sea water system",
         "metadata": {},
         "id": 4181031623333192,
         "createdTime": 1562764416913,
         "lastUpdatedTime": 1562764416913,
         "rootId": 4181031623333192
       },
       {
         "externalId": "PUMP_A",
         "name": "Pump",
         "parentId": 4181031623333192,
         "description": "Main pump for system 11",
         "metadata": {},
         "id": 2975365566518130,
         "createdTime": 1562764416913,
         "lastUpdatedTime": 1562764416913,
         "rootId": 4181031623333192
       },
       {
         "externalId": "Pump_B",
         "name": "Pump",
         "parentId": 4181031623333192,
         "description": "Backup pump for system 11",
         "metadata": {},
         "id": 1366019363753734,
         "createdTime": 1562764416913,
         "lastUpdatedTime": 1562764416913,
         "rootId": 4181031623333192
       },
       {
         "externalId": "HEATING_CABLE",
         "name": "Heating cable",
         "parentId": 2975365566518130,
         "description": "Heating cable for pump A",
         "metadata": {},
         "id": 3816457134628307,
         "createdTime": 1562764416913,
         "lastUpdatedTime": 1562764416913,
         "rootId": 4181031623333192
       }
     ]
   }

In addition to externalId you get a unique id field and value. References within CDF use that id, so parentExternalId is translated into that new unique identifier. Also, you have a new rootId field that gives you the id of the root asset.