Working with Dataverse / CDS in offline scenarios

[Livi_1]

Hi,

I am developing a solution which requires a set of relational database tables to operate in an offline situation. We need to be able to add new records and edit/delete these records while offline without an internet connection. Then be able to synchronise it once an internet connection is re-established.

I have been reading on Greg Lindhorst's blogs and want to implement the ability to traverse through my relational data. 

https://powerapps.microsoft.com/en-us/blog/relate-records-in-many-to-many-relationships/

https://powerapps.microsoft.com/en-us/blog/one-to-many-relationships-for-canvas-apps/ 

However I'm  not sure this functionality is still possible once I save my CDS data to an offline cache and local collection.

Will the relationship between tables still be maintained after I save each individual CDS entity to a local cache? Will I still be able to navigate across the different tables?

Thanks all.

[v-bofeng-msft · Accepted solution]

Hi @Livi_1 :

I've made a test, the conclusion is that the collection can not save the relationship between entities.
When a user is suddenly offline, he may still be able to see a related record recorded in another table, because the data has been cached locally. But even so, as long as the app is closed and opened while offline, the data will still be cleared.
In addition, because Dataverse is a cloud service, once the user is offline, the data in the data source cannot be modified and accessed. The only thing you can see is the temporary data that has been cached.

My suggestion is:

If you want to create an offline application, I suggest you add a primary key and foreign key to your data table to associate the two tables instead of using ‘relationship’

Best Regards,

Bof

[EricRegnier]

Hi @Livi_1,

I assume you are using Dataverse and model-driven apps. If so, relationships and lookups still work offline, otherwise there wouldn't be much purpose of going offline as Dataverse is a relational database in the backend. Here's more info on the offline: https://docs.microsoft.com/en-us/dynamics365/mobile-app/preview-setup-mobile-offline

And its limitations: https://docs.microsoft.com/en-us/dynamics365/mobile-app/mobile-offline-capabilities

Note: even though it says Dynamics 365, it's the same principal for Dataverse (CDS)

Hope this helps!

[Livi_1]

Thank you. I'm working with a canvas app. However looking at the limitations it seems the offline functionality is only available for certain entities. In my case I will be creating custom entities so I think its not supported. Thank you for your help.

[Livi_1]

Thank you. That makes a lot of sense to me. I'll most likely proceed with a primary key and foreign key approach.

[EricRegnier · Accepted solution]

Custom entities are supported. Might be worth looking at model-driven apps since that would be handled out-of-the-box with minimal effort?

[Livi_1]

Thanks @EricRegnier . I can't believe I missed that line. I don't have any Dynamics 365 licence. It seems like I can still work with custom entities with just a Microsoft 365 Premium licence. Is a worthwhile test. Many thanks!