On Tue, Nov 16, 2010 at 4:41 AM, byrnejb <[email protected]> wrote:
> > > On Nov 14, 5:07 am, Gary Doades <[email protected]> wrote: > > On 13/11/2010 9:48 AM, flebber wrote:> Hi > > > > > Looking for a little assistance. I am trying to create a basic > > > database schema using Ruby, Sequel and Sqlite3. > > > > > I am reading herehttp:// > sequel.rubyforge.org/rdoc/classes/Sequel/Database.html#M000510 > > > andhttp://www.firstsql.com/tutor6.htm. > > > > > The only thing that would be unusual about my db is that I want to use > > > two primary keys time& date as no more than one event can occur at > > > any time though multiple events could occur on a day. I am not > > > understanding in sequel how to correctly create a db with multiple > > > keys? Or should I just be generating a random number to create a key > > > which references date and time? > > > > First. You can only have one primary key. That is what he word > primary means. > > Second. You do not need, and really do not want, a composite primary > key. What you need is a composite index with a uniqueness > constraint. > > Third. When you say "no more than one event can occur at any time" are > you saying that no more than one event can 'start' at a given time but > that events can nonetheless overlap. Say, one starts at 09:00 and > runs to 11:00 but another starts at 10:15 and runs until 10:45? Is > that allowed? If not, then your constraint as given is insufficient > for your purpose. > > -- > You received this message because you are subscribed to the Google Groups > "sequel-talk" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<sequel-talk%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/sequel-talk?hl=en. > > Time for an event is given as a start time, just an identifier, there is actually no end time. -- You received this message because you are subscribed to the Google Groups "sequel-talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sequel-talk?hl=en.
