This is something I have thought a lot recently since I recently saw a project that absolute didn’t care in the slightest about this and used many vendor specific features of MS SQL all over the place which had many advantages in terms of performance optimizations.
Basically everyone always advises you to write your backend so generically with technologies like ODBC, JDBC, Hibernate, … and never use anything vendor specific like stored procedures, vendor specific datatypes or meta queries with the argument being that you can later switch your DBMS without much hassle.
I really wonder if this actually happens in the real world with production Software or if this is just some advice that makes sense on surface level but in reality never pans out. I personally haven’t seen any large piece of Software switch to a different DBMS, even if there would be long term advantages of doing so, because the risk and work to retest everything would be far too great.
The only examples I know of (like SAP) were really part of a much larger rewrite or update rather than “just” switching DBMS.
My colleague was working on migrating around dozens of batch jobs written in Java. All jobs had JPA/Hibernate but people which were writing those jobs didn’t understand abstraction and encapsulation. It end-up as vendor locked as you can imagine. Procedures, reading cursors, Oracle specific functions, metadata, logic spread between Java and PL/Sql, all the fun stuff, you know. So it took around one year of work to migrate to Postgres. And that’s with support of DBA who was helping with rewriting most complicated queries and procs. So yeah, don’t worry about that DBMS specific features.
Don’t get me wrong, though. Efforts spent on making design decisions should be proportional to potential size/complexity growth of the software. If you building todo list , how many different queries you might have in fairly pessimistic scenarios? Maybe couple dozens. Don’t bother with JPQL or HQL. If you expect your app to grow significantly. I’d do as much as possible to avoid my colleague’s fate.