PostgreSQL: Is it better to use multiple databases with one schema each, or one database with multiple schemas?

Question

After this comment to one of my question, I\'m thinking if it is better using one database with X schemas or vice versa.

My situation: I\'m developing a web applicat

Answer 1

In a PostgreSQL context I recommend to use one db with multiple schemas, as you can (e.g.) UNION ALL across schemas, but not across databases. For that reason, a database is really completely insulated from another database while schemas are not insulated from other schemas within the same database.

If you -for some reason- have to consolidate data across schemas in the future, it will be easy to do this over multiple schemas. With multiple databases you would need multiple db-connections and collect and merge the data from each database "manually" by application logic.

The latter have advantages in some cases, but for the major part I think the one-database-multiple-schemas approach is more useful.