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Comment by z3t4 | Hacker News Reader

When I started working with databases about 20 years ago talking to peers it was common to have a layer in-front of the database so that you could easily replace the database. It felt stupid until I actually had to do a database migration... So do you still put a layer infront of the database so that you can for example easily change from mySQL to Postgress? Given there are so many open source database I think there is less need to do so... Or do you go all in vendor lock in? Or some middle ground?

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I believe you are talking about the Microsoft ODBC API which was language and platform agnostic data acquisition layer. Early versions of it had pretty bad performance issues if I remember correctly, but eventually it became somewhat useful.

I believe that developers back in the 90's wanted a way to "drop in" various low and higher cost DBMS systems to their client-server based apps without the need of hiring full-time database sysops.

That would be an ORM or something similar, I think. It's not realistic unless you're always testing with two databases from the start, because their implementation details leak through.

It can be useful if your program is simple enough to work with both MySQL and SQLite, but often you should just stick with one DB and get to use all its features.

[ServiceStack OrmLite][1] does just that, all our development is done locally using SQLite but then deployments use MySQL. We do fall into the 'program is simple enough' category though.

[1]: https://github.com/ServiceStack/ServiceStack.OrmLite

You can indeed have that and many people do, but the problem with going that route is you can only use the lowest common denominator of features of any of the target databases, which wipes out a lot of the performance or convenience features you'd get from either.

(arguably SQL itself is/was supposed to be that common layer in the first place, but db vendors always want to be able to present users with new features that are not yet standardized)

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