[eftpotrm]

Not just Postgres; any database server in which you can do either stored procedures or submit arbitrary batches of SQL statements rather than just individual queries will let you do this. I routinely do in MS SQL Server, for example, and have worked on multiple projects where the ability to do this was utterly critical to overall performance.

To be perfectly honest, I'd consider any database server where I couldn't do this to be something of a toy because of the restrictions it places on overall app performance. It might be OK in SQLite or Access but a real database? Sorry, no, come back when you've finished the thing please.