I believe that in order for you to solve this connection issue, you should configure the Relational Data Sources properly on the PI Data Services Administration page.
Please go to the PI Data Services Administration page.:
http://sharepointserver/PI Data Services/Admin/
And then click on "Relational Data Sources".
Now, you should create a new Data Source with the same name that you were using on your SVG display on PI ProcessBook.
On “Database Type”, please select SQL Server and you should use a connection string similar to:
What is important is that you test the connection, making sure you have enough permission to access your SQL Database from your SharePoint Server.
Following the procedure above, you should be able to view the SQL Database data on your display shown by PI Graphic Web Part.
Hope this post is helpful to you!