You were never meant to do that with SQL

There seems to be a lot of hatred for SQL in the world at the moment: I can’t think of any other reason why the term NoSQL would catch on in the way that it has, when the key technological distinction is actually the lack of ACID guarantees (which are entirely orthogonal to whether or not SQL is used, as evidenced by non-ACID MySQL and HiveQL, which offers a pretty familiar SQL-like interface on an entirely non-traditional backend).

I wonder whether one of the unspoken reasons for this hatred is that at one point or another almost everyone has ended up doing this sort of thing:

   builder.Add("SELECT foo FROM bar WHERE id = ");

   if (additionalConstraint)
      builder.Add(" AND frobbable = 1 ");

   /* ... ad nauseam ... */

SQL is a hard language to like: it’s never been properly standardised (or rather, it has, but the standard has never been implemented) meaning that you spend too much time worrying about compatibility. Its theoretical underpinning is poor, leading to constructions that are hard for the engine to optimise (meaning more manual work).

However, SQL is a language in its own right, and was never intended to be generated programmatically by another programming language. This shouldn’t come as a surprise, as I struggle to think of any programming language that has been designed to work in this way.

Using SQL from a decent command-line environment is a powerful tool and often a pleasure to use. By comparison, generating SQL programmatically is an abomination that would be worth of The Daily WTF were it not for the fact that nobody’s ever invented an API that offers the same flexibility.

Personally, I blame the vendors. Until RDBMSs can offer the same quality of optimisation that modern compilers can (that is, write in a high-level language and never even think about micro-optimisation) high-performance relational database access will remain a sea of vendor-specific optimiser hacks. Maybe there’s a theoretical reason why optimisers will never be this good, in which case perhaps we do need to abandon the relational model in practice. But let’s not pretend it has anything to do with SQL.

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