It's an Email service implemented in SQL Server database.
This service has some basic Emailing features including: signing up/in, deleting account, sending Emails, displaying Emails list, reading & deleting Emails, blocking other users, etc.
This service has a console user interface that is implemented in C#. No logic part is in UI codes.
You can find all SQL codes in ALL.sql file. UI files are in Foofle folder.