On Tuesday, February 1, 2022, Дмитрий Иванов <firstdis...@gmail.com> wrote:
> ср, 2 февр. 2022 г. в 09:19, David G. Johnston <david.g.johns...@gmail.com > >: > >> On Tue, Feb 1, 2022 at 8:15 PM Дмитрий Иванов <firstdis...@gmail.com> >> wrote: >> >>> Why are COLUMN GENERATED ALWAYS AS called "methods" and singled out as a >>> separate field type? >>> >> >> This sounds like you are describing something written. Can you provide a >> link to where that is? >> >> It is possible to give a link, but it would require authorization: >>> >>  > Here are the contents of the topic: > > DEFAULT VALUE <> GENERATED ALWAYS AS STORED > the DEFAULT value is not recalculated when the reference column are > changed. is not an identical construction GENERATED ALWAYS AS STORED > > *reply:* > They are in a separate list “Methods”. > This approach was used for other databases *long before* generated > columns were implemented in PostgreSQL. > ==================== > > It has to do with the syntax of generated and that you can generate data in different ways. Calling those ways “methods” seems reasonable. > >> >> Which community? There are many ways in which a "data schema [can be] >> presented as data". In PostgreSQL there is only a single source of truth >> for what the data schema is - the "System Catalogs" [1]. Those tables are >> made available to the user in the pg_catalog schema. >> >> I came across a long acronym defining the name of the approach, then I >> decided that to come up with something fundamentally new is difficult >> enough. That everything already has a formal name. But I can't find it >> anymore. I need it to position my solution. >> > Shema - shema > Table Entity > id | propery1| property2| property3 > > Shema-data > > Table Entity > id| name > > Table Property Entity > id | id_entity | name| val > The Shema-data thing is called the Boogyman pattern because teachers use it to scare students and illustrate what not to do when designing a data model. You can also find it abbreviated “EAV anti-pattern” where EAV stands for entity-attribute-value. David J.
