Re: [Pharo-users] [Voyage] Using OID as a domain object identifier
Am 29.07.2013 um 19:34 schrieb Esteban A. Maringolo : > 2013/7/29 Norbert Hartl : >> Am 29.07.2013 um 15:46 schrieb "Esteban A. Maringolo" : >>> Is it a good practice to use the OID value (anInteger) as an >>> "external" identifier of your domain object? >>> ... >>> I like OID/UUIDs, and I don't want to duplicate that logic in my app. >>> >> I think for your purpose OID will be fine but I'm not sure. I use UUIDs. You >> can instruct mongo to use a UUID instead of an OID. Works flawlessly. > > How do you do that? Because OID's are a BSON native artifact, > efficient in terms of storage and lookup (a 12 byte integer in the > end...) > > Is there a way to have an smaller UUID? more like the first eight > chars of a Git commit or similar… If you look at [1] you can see that UUID is a native BSON artefact as well. Pharo has a UUID class. I extended the Mongo driver to serialize UUID properly. So basically all you need is to put a UUID object in your model object and serialization should be automatic. Of course you need to tell the serialization layer to serialize it as _id. But it is fully supported on mongo. Performance wise it is said it might be a tad slower than object ids. But if you have doubts about object ids you should be willing to take the payoff. I can't help here much because I have my own serialization layer that is pretty much superseded by Voyage. Do you have really performance problems why you like to restrict the key size? That would be a bad because you would restrict the uniqueness to a useless artefact. IIRC mongo does that for you anyway. There is a certain size of key mongo evaluates first and rechecks on collision. But I'm not sure I had only the impression the same techniques are in charge as for other hashing problems. hope this helps, Norbert [1] http://bsonspec.org/#/specification
Re: [Pharo-users] [Voyage] Using OID as a domain object identifier
2013/7/29 Norbert Hartl : > Am 29.07.2013 um 15:46 schrieb "Esteban A. Maringolo" : >> Is it a good practice to use the OID value (anInteger) as an >> "external" identifier of your domain object? >> ... >> I like OID/UUIDs, and I don't want to duplicate that logic in my app. >> > I think for your purpose OID will be fine but I'm not sure. I use UUIDs. You > can instruct mongo to use a UUID instead of an OID. Works flawlessly. How do you do that? Because OID's are a BSON native artifact, efficient in terms of storage and lookup (a 12 byte integer in the end...) Is there a way to have an smaller UUID? more like the first eight chars of a Git commit or similar... Regards, Esteban A. Maringolo
Re: [Pharo-users] [Voyage] Using OID as a domain object identifier
Am 29.07.2013 um 15:46 schrieb "Esteban A. Maringolo" : > Hi all, > > Is it a good practice to use the OID value (anInteger) as an > "external" identifier of your domain object? > > Let's suppose I have a collection of "People", as I save them in the > collection, it will automatically create OIDs for them. > > But let's suppose I want to map that person to a RESTful URI, would it > be "legal" to use its OID as part of the URI? > > E.g. mydomain.com/people/123456790 > where 123456790 is the OID value. > > I like OID/UUIDs, and I don't want to duplicate that logic in my app. > I think for your purpose OID will be fine but I'm not sure. I use UUIDs. You can instruct mongo to use a UUID instead of an OID. Works flawlessly. Norbert
