Lets say when we are working on a Work Object, we have to be notified that an Entry say Bill # already exists in the system. We have to check both the Pega Internal DB and also external Databases to make sure that if user tries to enter an existing Bill number in either internal or external db, an error should be shown that it already exists.
What approach for internal db and external db should i be looking for?
You need to run query post the bill number is entered for both external and internal DB.
Better solution would be to use Data page that would have the particular column and is sourced collectively by data from both the ext and internal DB.