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]. For more options, visit this group at http://groups.google.com/group/sequel-talk?hl=en.
