On 1 July 2015 at 17:16, John Lahr <[email protected]> wrote: > Colin > > Thanks for your answer. The student/class thing was just an example - the > actual stuff I'd be building has nothing to do with students and classes it > was just the easiest thing that came to me. > > You can do a validation on a total number of related records? I did not > know that.
You can write a custom validation to do anything you like. The world is your mollusc. Colin > > On Wed, Jul 1, 2015 at 8:59 AM, Colin Law <[email protected]> wrote: >> >> On 1 July 2015 at 16:51, John Lahr <[email protected]> wrote: >> > Can you limit the number of related records a given parent record has? >> > >> > Example. Class/Student relatoinship. A Class has_many students but I >> > want >> > to limit the size of a class to a max 30 (of course minimum or exact >> > numbers >> > would hopefully work the same way?) >> >> There may be a better way but I would just use a validation that >> prevents further students being added to the class when the limit is >> released. >> >> By the way, can a student be in more than one class? If so then you >> need has and belongs to many or (which I prefer) has many through. >> >> Colin >> >> > >> > >> > -- >> > You received this message because you are subscribed to the Google >> > Groups >> > "Ruby on Rails: Talk" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> > an >> > email to [email protected]. >> > To post to this group, send email to [email protected]. >> > To view this discussion on the web visit >> > >> > https://groups.google.com/d/msgid/rubyonrails-talk/aadce5fd-8e2a-4596-9b68-b88c952354a2%40googlegroups.com. >> > For more options, visit https://groups.google.com/d/optout. >> >> -- >> You received this message because you are subscribed to a topic in the >> Google Groups "Ruby on Rails: Talk" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/rubyonrails-talk/IvBfZMAFC7g/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> To post to this group, send email to [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/rubyonrails-talk/CAL%3D0gLu3J0a8d0p8dEsmcmaQYwPMYZaMu%2BQ2wCCG3A8iOzbehw%40mail.gmail.com. >> For more options, visit https://groups.google.com/d/optout. > > > -- > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Talk" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/rubyonrails-talk/CAEBjNa2e7-r8Uq0rrta9N9%2Bx0BROTXBJEq4UE9jgNWzv4H_g9Q%40mail.gmail.com. > > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/CAL%3D0gLsE0X3p%3Dd0Nh6HckfBg8T_FCGVAaBMWdc3JhP4DAe025g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
