John I don't think this will work in the scenario provided as couldn't a user technically be on 2 machines in a disconnected state?
If you bring machine into the fold then you have reinvented hilo :) Greg On Wed, Apr 15, 2009 at 8:40 PM, John Rayner <john.ray...@conchango.com> wrote: > > You could also consider constructing your own unique identifier, e.g. > a sequence number combined with an idenfitier of your operator. > There's some good arguments to try and avoid using the database as the > source of unique identifiers. > > You also might not need to have this identifier as the primary key on > your table. For example, do you (or might you) want to persist orders > without creating an order number? > > Cheers, > John > > On Apr 15, 6:45 pm, Caio Kinzel Filho <cai...@gmail.com> wrote: >> Hm... I see... >> >> Thanks for the idea. >> >> >> >> On Wed, Apr 15, 2009 at 2:41 PM, Greg Young <gregoryyou...@gmail.com> wrote: >> >> > no hilo and that are two different methods ... but you could pretty >> > easily put them together ... >> >> > hilo generates a base 2 number (usually displayed as a base 10 number) >> > just make it base 36 .... >> >> > Cheers, >> >> > Greg >> >> > On Wed, Apr 15, 2009 at 1:37 PM, Caio Kinzel Filho <cai...@gmail.com> >> > wrote: >> >> >> Is there a way I ensure that HiLo will generate for the 80bit key, >> >> only combinations of letters/numbers? >> >> >> On Wed, Apr 15, 2009 at 2:18 PM, Greg Young <gregoryyou...@gmail.com> >> >> wrote: >> >> >>> Assuming this is all so you can be occasionally connected and still >> >>> generate an id >> >> >>> do id checkouts ... say each occasionally connected client has 1000 >> >>> ids and when they run out they check out new ones ... >> >> >>> use things with enough randomness ... using letters helps with >> >>> representing these ... you can fit a random 80 bit number into a much >> >>> smaller character field (numbers/characters). Your chance of collision >> >>> at 1/2^80 is small enough for most systems ... >> >> >>> use something similar to nhibernate's hilo generator. >> >> >>> Greg >> >> >>> On Wed, Apr 15, 2009 at 1:12 PM, Caio Kinzel Filho <cai...@gmail.com> >> >>> wrote: >> >> >>>> I agree with you on "generally they receive an id when they reach a >> >>>> central system", >> >> >>>> but my scenario is a little bit different: >> >>>> The "user" actually is a company operator, placing orders received by >> >>>> phone for a customer. >> >>>> The customer must receive an order id, for tracking purposes, etc >> >>>> The order is placed but its state is not yet "Confirmed" ( _that_ will >> >>>> happen when the order is processed by the central system) >> >> >>>> On Wed, Apr 15, 2009 at 2:02 PM, Greg Young <gregoryyou...@gmail.com> >> >>>> wrote: >> >> >>>>> Thsoe types of numbers are not generally created assigned in an >> >>>>> occasionally connected system ... maybe I am misunderstanding you ... >> >>>>> generally they receive an id when they reach a central system. >> >> >>>>> On Wed, Apr 15, 2009 at 1:00 PM, Caio Kinzel Filho <cai...@gmail.com> >> >>>>> wrote: >> >> >>>>>> One scenario: >> >>>>>> A user post an order, and receives as a confirmation, an order number >> >>>>>> (which must be unique and so, it's my primary key). >> >>>>>> It would be akward to see something like: >> >> >>>>>> "Your order is: 3F2504E0-4F89-11D3-9A0C-0305E82C3301" >> >> >>>>>> On Wed, Apr 15, 2009 at 1:56 PM, Greg Young <gregoryyou...@gmail.com> >> >>>>>> wrote: >> >> >>>>>>> Why do you want human readable keys? >> >> >>>>>>> On Wed, Apr 15, 2009 at 12:53 PM, caiokf <cai...@gmail.com> wrote: >> >> >>>>>>>> Hi, >> >> >>>>>>>> Which approach do you guys suggest to handle Primary Keys in an >> >>>>>>>> occasionally connected system? >> >> >>>>>>>> In my understanding, the options are: >> >> >>>>>>>> - GUIDs/UUIDs : which present a non-human readable key, which I want >> >>>>>>>> to avoid. >> >>>>>>>> - AppID, ID: difficult to mantain the AppID for all the clients, >> >>>>>>>> and I >> >>>>>>>> think it kind of polute my domain. >> >>>>>>>> - Some sort of Primary Key Pool: how could I integrate that with >> >>>>>>>> NHibernate in a (most) transparent way (as possible)? >> >> >>>>>>>> If someone has some other suggestion or stories about that matter, >> >>>>>>>> it >> >>>>>>>> would be very helpfull. >> >> >>>>>>>> Thanks, >> >>>>>>>> Caio >> >> >>>>>>> -- >> >>>>>>> It is the mark of an educated mind to be able to entertain a thought >> >>>>>>> without accepting it. >> >> >>>>> -- >> >>>>> It is the mark of an educated mind to be able to entertain a thought >> >>>>> without accepting it. >> >> >>> -- >> >>> It is the mark of an educated mind to be able to entertain a thought >> >>> without accepting it. >> >> > -- >> > It is the mark of an educated mind to be able to entertain a thought >> > without accepting it.- Hide quoted text - >> >> - Show quoted text - > > > -- It is the mark of an educated mind to be able to entertain a thought without accepting it. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "nhusers" group. To post to this group, send email to nhusers@googlegroups.com To unsubscribe from this group, send email to nhusers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/nhusers?hl=en -~----------~----~----~----~------~----~------~--~---
