Hello Sadok,

This extended field might be available in “App_Runtime” folder in extended DAC. 

In your project solution, the same DAC you need to extend and add the same field and then by using this extended DAC, you can get this field in your graph and just do a cache update for that particular DAC.

Hope this helps!

There’s probably nothing blocking it:
Use Visual Studio with .NET and C# to query - Azure SQL Database & SQL Managed Instance | Microsoft Docs

However there is no built-in library in Acumatica to do so. Direct access to database bypass all security measures and increases risk of data corruption. The most direct method to interact with a database in Acumatica is the PXDatabase class. This requires a valid DAC class for minimal data integrity  validations: Direct Database Updates with PXDatabase – Acumatica.dev

Accessing directly the database from within an Acumatica customization is highly discouraged.