Another unusual usage for SQL databases (today!) is as a data type server. SQL databases have a very rich set of data types with rigorous specification and myri

Another unusual usage for SQL databases (today!) is as a data type server. SQL databases have a very rich set of data types with rigorous specification and myriad operators, conversions, etc for all the types, more so than just about any other programming environment. If you need correct support for a complex data type operation in a development environment with weak or non-existent type support, you can use a SQL runtime to do that computation for you over a local client connection. I've used PostgreSQL this way a few times to great effect. The connection is over local IPC and never touches storage, so the operation throughput is quite high.