We show a privacy-preserving and performance-preserving approach to provably transform any database search protocol into a (pull-mode or batch-mode) publish-subscribe protocol, and viceversa. This enhances functionality of both protocol types, notably implying practically efficient publish-subscribe solutions for a large class of subscriptions (e.g., index, keyword, range and conjunction). Previous work either missed practicality or focused on customized solutions for specific subscription types. We also show simple padding techniques that enhance the confidentiality of database search and publish-subscribe protocols against communication eavesdroppers. Specifically, these techniques provide optimal hiding of the number of matching database records or publications, while restricted to keeping the communication increase below a specified limit.