On 28 Feb 2024, at 17:08, Guyren Howe <guy...@gmail.com> wrote: > > I am to talk about Postgres’s type system at PGConf: > > https://postgresconf.org/conferences/2024/program/proposals/postgres-s-type-system > > I picked the issue because I think it’s poorly understood, greatly > under-discussed, and an excellent way to empower postgres users. > > I am reasonably conversant with the issue. I’m not looking for others to > write the talk for me, but in order to make the best talk I can, I’m asking: > > What would you want to see in such a talk? > > I’m planning on covering: > > - The built-in types that are underused and their advantages (eg inet) > - domains > - such things as details of arrays including multidimensional arrays > - user-defined types, their relationship to tables, and generally how to use > them > > I would spend most of the time discussing ways to make effective use of > types. Some examples: > - defining functions of rows so the table can be used kind of like a set of > objects (including the dot notation for invoking functions) > - using UDFs to make code clearer eg if you have an idiosyncratic functional > index, define it using a function of the row, so it’s easy to get right when > querying > - using UDFs as a kind of better domain. eg differentiating imperial from > metric units by requiring an explicit constructor, not just accepting any old > number > > I would mention enumerated types, although I’m inclined to advise that their > inflexibility (eg can’t delete or rearrange them) means that a related table > is probably better (I’d be delighted to be proved wrong). > > Custom Range Types are an interesting feature, but I can’t think of a good > use case. Any good examples? > > Automatic casting is a feature I’m aware of, but I’d be interested in any > cool use cases. > > > Anything I’m missing? Any existing good discussions of the subject?
Any gotchas about user defined types or arrays? I was only planning on discussing simple user defined types, without going into writing the optional features in C. What is worth saying about custom range types? What even would be a good use case? A range of strings or ip address ranges, something like that, I suppose? Is there a good case for enumerations versus a fk to a table? I guess if you’re sure you won’t need to change the values in the enumeration? Days of the week, that sort of thing.
