Hi Ryan, I hope my question did not offend you. I didn't expect that the answer to this question would be considered to be that obvious.
Best, Manuel On Mon, May 13, 2019 at 9:57 AM R Smith <ryansmit...@gmail.com> wrote: > On 2019/05/13 12:56 AM, Manuel Rigger wrote: > > Hi everyone, > > > > It seems that a table created in the temp database cannot have a parent > > table that is created in the main database and vice versa: > > > > PRAGMA foreign_keys=true; > > CREATE TABLE t0 (c0 PRIMARY KEY); > > CREATE TEMP TABLE t1 (c0, FOREIGN KEY(c0) REFERENCES t0(c0)); > > INSERT INTO t1(c0) VALUES (1); -- no such table: temp.t0 > > > > Is this intended? It somehow seems so, since the parent table can also > not > > be prefixed by "temp." when declaring the foreign key in the above > example. > > However, I did not find a note in the documentation that this is not > > supported. Would it make sense to describe this in the limitations at > > https://www.sqlite.org/foreignkeys.html? > > > While the "why" of it has been handled by others, the question of "need > it be documented" still remains, to which I can comment: Documenting the > fact that FK relationships cannot be maintained across different > database entities, trespasses on two documentation conventions: > > A - Do not document the obvious (i.e. no point documenting the fact that > your car needs all 4 wheels for correct operation)[1], and > B - Do not document the negative (i.e. Say what you CAN do [short list] > rather than what you CAN'T [infinite list]) - unless it is an expected > yet omitted behaviour (such as things that can normally be done in other > databases, but not in this one)[2]. > > > > Cheers, > Ryan > > > [1] - Rant: There seems to be a senseless move to document exactly such > silliness for fear of litigation these days, making modern documentation > more and more a self-indemnification checklist by the manufacturer > rather than a helpful description of the operation and functionality of > the item. It used to be that the number 1 source of information about > the vehicle/device you purchased was its manual (written by Engineers), > now it's more TLDR; (edited by PR/Legal people) and for real information > you simply pray there is a youtube video on the issue by another > enthusiast. > > [2] - I know MSSQL "allows" temp tables to have foreign keys specified, > but it doesn't enforce the constraint, so it's nothing more than no-op > syntactic sugar, perhaps in an effort to not have it choke on > copy-pasted schemata. > > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
