Can you list the main pattern that serves as the opposite of the approach of allocating a separate database for each microservice?

The opposite of the approach of allocating a separate database for each microservice is the "Shared Database" pattern.

In this pattern, multiple microservices use the same database, which simplifies data exchange and consistency but reduces isolation and can lead to scalability and deployment independence issues.

Thus, while the approach with a separate database for each microservice provides isolation and independence, the shared database pattern is a centralized data storage for multiple services.