Programming

I used to be full on the ORM train. Now I’m a little less enthusiastic. What I actually think people need most of the time is something closer to ActiveRecord. Something that can easily map a result set into a collection of typed objects. You still generally write parameterized SQL, but the work of translating a db decimal into the correct target type on a record object in your language is handled for you. In .net, Dapper is a good example.

I also think most people overemphasize or talk about how other programmers “suck at SQL” waaayy too much.

IMO, for most situations, these are the few high-level things that devs should be vigilant about:

• parameterize all sql.
• consider the big-o of the lookups/writes (sometimes an app join or pulling a larger set and filtering in memory is better than crafting very complex projections in sql). This is a little harder to analyze with an ORM, but not by much if you keep the mappings simple and understand the loading semantics of the ORM.
• understand the index coverage of queries and model table keys properly to maintain insert performance (monotonically increasing keys).
• stop fixating on optimizing queries that run in a few seconds, a few times a day. Optimize the stuff that you run on every transaction - if you need to.

On most of those points, if you don’t have aggregate query counts/metrics on query performance on your clusters, starting to get cute with complex queries is flying blind, and there’s no way to prioritize what to optimize.

For the vast majority of cases, simple, obvious selects that don’t involve special db features are going to do the job for most applications. When the database becomes a bottleneck, there are usually most more effective ways to handle them than to try to hand optimize all the queries.