Greetings everyone, I'm wondering, is there any way to get DTDL of the complete Digital Twin setup, the one that includes Digital Twin instances and relationships? I know there is a python SDK library to manage Digital Twin resource, but I can't find a single command/method to fetch complete DT setup. There is an example ( https://learn.microsoft.com/en-us/azure/digital-twins/how-to-query-graph ) where you can get all digital twin instances by using query commands, or to get relationships based on Digital Twin instances. In order to get a complete setup, I would have to make several requests and combine them together. Thanks in advance

There is no single command that will get the complete content of the Digital Twin graph. However, you can do it by making multiple calls through the SDK. The approach is as follows: Query all the twins query_expression = 'SELECT * FROM digitaltwins' query_result = service_client.query_twins(query_expression) Loop through the results and get the Incoming or Outgoing relationships for each twin. service_client.list_relationships(digital_twint_id) You can also get all the models through the SDK listed_models = service_client.list_models() There's documentation for the Python SDK

How to get DTDL of complete Digital Twin setup?

Accepted answer

Matthijs van der Veer 4,376 Reputation points MVP

2022-08-25T15:24:49.677+00:00
There is no single command that will get the complete content of the Digital Twin graph. However, you can do it by making multiple calls through the SDK. The approach is as follows:

Query all the twins

query_expression = 'SELECT * FROM digitaltwins' query_result = service_client.query_twins(query_expression)

Loop through the results and get the Incoming or Outgoing relationships for each twin.

service_client.list_relationships(digital_twint_id)

You can also get all the models through the SDK

listed_models = service_client.list_models()

There's documentation for the Python SDK
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2 people found this answer helpful.
Domagoj Bazina 221 Reputation points

2022-08-29T07:38:01.68+00:00

Hello @Matthijs van der Veer ,
thanks for the answer.

Solution that you have proposed is similar to the one I was thinking about, however it has small "disadvantage" and that is time.
Solution includes 3 different HTTP calls to the Digital Twin resource and that takes time, probably one call would be faster.

I spent some time looking at documentation, especially this section (https://learn.microsoft.com/en-us/azure/digital-twins/how-to-query-graph#query-by-relationship) and if I didn't get anything wrong, query expressions are only used to retrieve Digital Twin instances. There is no option to retrieve DTDL models or relationships using query expressions? Latter may be used to query Digital Twin instances as parameters of query expression?

Thanks in advance!

Matthijs van der Veer 4,376 Reputation points MVP

2022-08-29T08:10:52.78+00:00

You're right to conclude you can't get models as a result of a query. You can get a relationship as a result. In the documentation, there is a sample where the relationship is selected as well. This works if you know the relationship that the model has when building the query. The proposed solution will be easier, but you're right to say it includes three different calls. I hope to see some export/snapshot feature for this product sometime soon, but since the pricing model of ADT is per API call, I don't think it will happen anytime soon.

Domagoj Bazina 221 Reputation points

2022-09-01T11:49:01.643+00:00

I have one more question, maybe I should open another topic, however I would like to discuss it with You.

Let's say, I've created Digital Twin Setup, that includes 2 DTDL Models, one model represents Room and other one represents Temperature sensor. Afterwards, I've created DT instances from those models, one room instance and three Temperature sensor instances. The DTDL model of the Room is configured to implement targeted Relationship with the Temperature sensor model. Now, I would like to implement a smoke detector or some other sensor, and that sensor is not compatible with the Temperature sensor model, as the Temperature Sensor model uses integer schema for value instead of boolean or some other value.
So, I have to create DTDL model for Smoke Detector, moreover I would like to connect it with the Room instance, in order to do that I have to delete existing Room Model and DT instance, create new one that supports relationship with the Smoke Detector instance and reconfigure complete setup.

One of the solutions would be to reconsider all the requirements before creating the complete Setup, eventually demand will appear to implement a new feature, and we would repeat process mentioned above . The other solution would be to incorporate non-targeted relationships, but that doesn't seem quite right. Maybe, multiple schema options or something like that would be useful.

What is Your advice on this topic?
Thanks!
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How to get DTDL of complete Digital Twin setup?

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