In which table/entity are email attachments stored (Base64)?

[alex93jansen]

We recently did an export of all tables in our Dataverse environment to create a backup of old Dynamics 365 data in SQL. However, we are struggling to locate the table that stores the actual Base64 of the email attachments/images that can be decoded. The only thing we have found thus far are attachment GUIDs which aren't useful by themselves.

[dpoggemann]

Hi @alex93jansen ,

Please review the following:  https://docs.microsoft.com/en-us/power-platform/admin/capacity-storage#summary-tab

The tables used for storage of the attachments are identified here.

[alex93jansen]

So if I understand correctly, the actual attachment files are stored in the File Storage, and tables use GUIDs to reference the files.

I followed this tutorial to access the File Storage, but it returns empty (no errors, no folders or files) https://docs.microsoft.com/en-us/power-platform/admin/storage-sas-token

[dpoggemann]

Hi @alex93jansen ,

The files are still stored in tables from my understanding, space for these specific areas are calculated as File storage by Microsoft.  See list below.  The Attachment table is the key table utilized to store attachments.  @EricRegnier , any feedback or differences from your background on this one...

SUMMARY TAB

Number

Description

(1)

Storage capacity usage File and database: The following tables store data in file and database storage: Attachment AnnotationBase Any custom or out-of-the-box table that has columns of datatype file or image (full size) Any table that is used by one or more installed Insights applications and ends in - Analytics WebResourceBase RibbonClientMetadataBase Log: The following tables are used: AuditBase PlugInTraceLogBase Database only: All other tables are counted for your database including the Dataverse search index

[EricRegnier · Accepted solution]

Hi @alex93jansen, @dpoggemann,

There are different types of storage in Dataverse.

• File column type which is a relatively new feature are stored in Blob and have a specific way to retrieve that data: https://docs.microsoft.com/powerapps/developer/data-platform/file-attributes 
  
  
• Email attachments is a old feature and files are stored in a different way.. These attachments are stored in the Attachment table in Azure SQL and can be access via the API. E.g.: https://docs.microsoft.com/dynamics365/customer-engagement/web-api/attachment 

The storage SAS link @alex93jansen provided is to retreive data form DataLake if Dataverse is exporting to DataLake which is completly different.

Hope this helps!

[alex93jansen]

Thanks @EricRegnier and @dpoggemann I was able to retrieve the email attachments from that table by using Power Automate.