On Sat, Aug 22, 2020 at 10:51 AM Bruce Momjian <bruce@momjian.us> wrote:
On Fri, Aug 21, 2020 at 08:41:54PM -0700, David G. Johnston wrote: > Adding CHECK constraints and -- > comments to the CREATE TABLE command would be a welcome addition. In > particular I noticed: > > paragraph: client host:port number > example: connection_from text, > > could become: > > connection_from text check(connection_from ~ '^[^:]+:[0-9]+$) -- the host and > port of the client, colon-separated
> I may pick this up in the future unless someone thinks it wouldn't be a good > idea. I would be removing the paragraph of field names and make the table > specification authoritative.
I am a little worried about adding this since the data is generated in an automated way, and might change, or some config value might change its format. I think the example is to show how to load, and adding extra constraints would just detract from the illustration, I think.
Good constraints wouldn't include specific values, just general structure when appropriate. The existing documentation already does this in the provided example - though relegating things to just comments would still be an improvement. I see it less as an illustration in the Config section and more of a specification. A config value changing its format is going to be something anyone using this example would have to understand and adapt to - it still seems worthwhile to have it fleshed out for the default.
The middle of the config section doesn't seem like a great place to teach that the COPY command exists.
