Checking for uniqueness within the database is good, like Geert suggested. If you want to make them unique across databases and servers assign each database and each server a unique prefix and prepend that to your "local" unique id. That will guarantee that it is unique across your platform.
This is actually a common pattern used by credit card providers, the first four digits of your credit card are unique to your provider the remaining digits are semi-random but unique to your card. That way they can guaranteed uniqueness across providers without the synchronization card numbers issued across organizations. Enjoy. Keith On Tue, Feb 13, 2018 at 7:53 AM, Geert Josten <geert.jos...@marklogic.com> wrote: > Hi Abhinav, > > sem:uuid-string() generates a 123-bit size random string, which makes > changes on collisions extremely rare. If you prefer being paranoid, and > want to check anyhow (there are various ways tocheck if an id or uri is > taken or not), you’d typically do that in one database only. You could also > do it across multiple databases, but the more you check and include, the > slower it obviously gets. > > There are some brief notes on this topic in the README of my ml-unique > library: https://github.com/grtjn/ml-unique > > Cheers, > Geert > > From: <general-boun...@developer.marklogic.com> on behalf of " > abhinav.mish...@cognizant.com" <abhinav.mish...@cognizant.com> > Reply-To: MarkLogic Developer Discussion <general@developer.marklogic.com> > Date: Tuesday, February 13, 2018 at 9:39 AM > To: "general@developer.marklogic.com" <general@developer.marklogic.com> > > Subject: Re: [MarkLogic Dev General] Unique GUID generation in MarkLogic > > Hi Geert, > > > Thank you for your response. > > > I guess it is just something we are wondering about. If we changed Servers > or hardware, would there be a chance for duplicates. There is no other > specific reason though. > > > Regards, > > Abhinav > ------------------------------ > *From:* general-boun...@developer.marklogic.com < > general-boun...@developer.marklogic.com> on behalf of Geert Josten < > geert.jos...@marklogic.com> > *Sent:* Tuesday, February 13, 2018 8:55 AM > *To:* MarkLogic Developer Discussion; general-request@developer. > marklogic.com > *Subject:* Re: [MarkLogic Dev General] Unique GUID generation in MarkLogic > > Hi Abhinav, > > Can you elaborate on what you mean with ‘unique across environments’? > > Cheers, > Geert > > From: <general-boun...@developer.marklogic.com> on behalf of abhinav > mishra <abhinavmishr...@gmail.com> > Reply-To: MarkLogic Developer Discussion <general@developer.marklogic.com> > Date: Tuesday, February 13, 2018 at 8:40 AM > To: "general-requ...@developer.marklogic.com" <general-request@developer. > marklogic.com>, "general@developer.marklogic.com" < > general@developer.marklogic.com> > Subject: [MarkLogic Dev General] Unique GUID generation in MarkLogic > > Hi All, > > We are exploring ways to generate GUIDs. We just want to be sure that the > GUIDs are unique always and we have a requirement that these GUIDs should > be even unique across environments. There should not be same GUID in two > MarkLogic environments > > We found sem:uuid-string() function from documentation and seems like a > good point to start with. However we are not sure if this method returns > unique across environments. > > Can someone guide or provide more information on GUID generation, any > third party open source library which we can use. > > Regards, > Abhinav > -- > Sent from my iPhone > This e-mail and any files transmitted with it are for the sole use of the > intended recipient(s) and may contain confidential and privileged > information. If you are not the intended recipient(s), please reply to the > sender and destroy all copies of the original message. Any unauthorized > review, use, disclosure, dissemination, forwarding, printing or copying of > this email, and/or any action taken in reliance on the contents of this > e-mail is strictly prohibited and may be unlawful. Where permitted by > applicable law, this e-mail and other e-mail communications sent to and > from Cognizant e-mail addresses may be monitored. > > _______________________________________________ > General mailing list > General@developer.marklogic.com > Manage your subscription at: > http://developer.marklogic.com/mailman/listinfo/general > > -- Keith "Do what you can, with what you have, where you are." - Theodore Roosevelt
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