August 2011 - Pharo-users - lists.pharo.org

Re: [Pharo-users] Serializing to/from Json

by Mariano Martinez Peck

On Tue, Aug 30, 2011 at 3:40 PM, Davorin Rusevljan < davorin.rusevljan(a)gmail.com> wrote: > On Tue, Aug 30, 2011 at 4:27 PM, Mariano Martinez Peck > <marianopeck(a)gmail.com> wrote: > > I don't understand. What is the difference from the querying and indexing > > point of view between serializing with JSON or a binary serializer. > > let's say you have a class: > > Object subclass: #MyClass > instanceVariableNames: 'a b' > classVariableNames: '' > poolDictionaries: '' > category: 'Example' > > and you serialize it into the json to something like > > { > '_id': 'lkjjfdjdjdj', > 'a': 'value of a', > 'b': 'value of b' > } > > than you can ask CouchDB to fetch you all object where for instance a is > 'Aha!' > > while if you serialize it as: > > { > '_id': 'lkjjfdjdjdj', > 'fuel_blob': 'AAXsdfkljijS3SM .....' > } > > CouchDB has no idea how to look into the a, and select appropriate objects. > > Interesting. Now I understand. So I guess the same happens with all the rest of NoSQL databases? I am right no assume that if I want to be able to do queries without bringing the whole graph into memory, I need to store the data in JSON ? thanks! -- Mariano http://marianopeck.wordpress.com

Aug. 30, 2011

Re: [Pharo-users] Serializing to/from Json

by Davorin Rusevljan

On Tue, Aug 30, 2011 at 4:27 PM, Mariano Martinez Peck <marianopeck(a)gmail.com> wrote: > I don't understand. What is the difference from the querying and indexing > point of view between serializing with JSON or a binary serializer. let's say you have a class: Object subclass: #MyClass instanceVariableNames: 'a b' classVariableNames: '' poolDictionaries: '' category: 'Example' and you serialize it into the json to something like { '_id': 'lkjjfdjdjdj', 'a': 'value of a', 'b': 'value of b' } than you can ask CouchDB to fetch you all object where for instance a is 'Aha!' while if you serialize it as: { '_id': 'lkjjfdjdjdj', 'fuel_blob': 'AAXsdfkljijS3SM .....' } CouchDB has no idea how to look into the a, and select appropriate objects. Davorin Rusevljan http://www.cloud208.com/

Aug. 30, 2011

Re: [Pharo-users] Serializing to/from Json

by Larry White

Couch stores data as Json. Its query capabilities are based on json pair names. I'm just trying it out but I believe that, for example, if a User object was a blob, you couldn't issue a query like "fetch user with username = 'foo'". You would have to read all the users into Smalltalk and do a select: Anyway that's my impression of how Couch works. On Tue, Aug 30, 2011 at 10:27 AM, Mariano Martinez Peck < marianopeck(a)gmail.com> wrote: > > > On Tue, Aug 30, 2011 at 9:40 AM, Davorin Rusevljan < > davorin.rusevljan(a)gmail.com> wrote: > >> On Tue, Aug 30, 2011 at 10:23 AM, Marcus Denker <marcus.denker(a)inria.fr> >> wrote: >> > >> > Does it need to be JSON? >> >> Since CouchDB stores data in json - I guess the answer is very likely >> yes, since just storing serialized blobs inside CouchDB would loose >> all querying and indexing available. > > > I don't understand. What is the difference from the querying and indexing > point of view between serializing with JSON or a binary serializer.<http://www.cloud208.com/> > > -- > Mariano > http://marianopeck.wordpress.com > >

Aug. 30, 2011

Re: [Pharo-users] Serializing to/from Json

by Sven Van Caekenberghe

On 30 Aug 2011, at 16:27, Mariano Martinez Peck wrote: > I don't understand. What is the difference from the querying and indexing point of view between serializing with JSON or a binary serializer. It could be (not knowing the specific database) that the db understands the contents and can query on the properties, which would make huge differences in performance. Say you store: 1 -> { "id" : 1, "name" : "one" } 2 -> { "id" : 2, "name" : "two" } â¦ 99999 -> â¦ You could then ask the db for the object where name = "one hundred" without reading all of them (but the db would have to do that of course). Maybe even indexes are possible. Sven

Aug. 30, 2011

Re: [Pharo-users] Serializing to/from Json

by Mariano Martinez Peck

BTW....I did experiments between Fuel and Riak, maybe that helps in something: http://marianopeck.wordpress.com/2011/08/16/when-fuel-meets-riak-nosql-data… On Tue, Aug 30, 2011 at 3:27 PM, Mariano Martinez Peck < marianopeck(a)gmail.com> wrote: > > > On Tue, Aug 30, 2011 at 9:40 AM, Davorin Rusevljan < > davorin.rusevljan(a)gmail.com> wrote: > >> On Tue, Aug 30, 2011 at 10:23 AM, Marcus Denker <marcus.denker(a)inria.fr> >> wrote: >> > >> > Does it need to be JSON? >> >> Since CouchDB stores data in json - I guess the answer is very likely >> yes, since just storing serialized blobs inside CouchDB would loose >> all querying and indexing available. > > > I don't understand. What is the difference from the querying and indexing > point of view between serializing with JSON or a binary serializer.<http://www.cloud208.com/> > > -- > Mariano > http://marianopeck.wordpress.com > > -- Mariano http://marianopeck.wordpress.com

Aug. 30, 2011

Re: [Pharo-users] Serializing to/from Json

by Mariano Martinez Peck

On Tue, Aug 30, 2011 at 9:40 AM, Davorin Rusevljan < davorin.rusevljan(a)gmail.com> wrote: > On Tue, Aug 30, 2011 at 10:23 AM, Marcus Denker <marcus.denker(a)inria.fr> > wrote: > > > > Does it need to be JSON? > > Since CouchDB stores data in json - I guess the answer is very likely > yes, since just storing serialized blobs inside CouchDB would loose > all querying and indexing available. I don't understand. What is the difference from the querying and indexing point of view between serializing with JSON or a binary serializer.<http://www.cloud208.com/> -- Mariano http://marianopeck.wordpress.com

Aug. 30, 2011

Re: [Pharo-users] [Esug-list] Slowly uploading ESUG Slides

by Sven Van Caekenberghe

Thanks a lot for posting the slides so quickly, now us poor souls who could not attend can at least see what we missed ;-) On 24 Aug 2011, at 13:11, Marcus Denker wrote: > Begin forwarded message: > >> Subject: [Esug-list] Slowly uploading ESUG Slides >> To: ESUG Members <esug-list(a)lists.esug.org> >> >> Hi, >> >> We are starting to upload the Slides of ESUG 2011: >> >> SlideShare: http://www.slideshare.net/esug/ >> Archive (PDF): http://esug.org/data/ESUG2011/Slides/ >> >> I will tweet every uploaded slide here: http://twitter.com/#!/esugsmalltalk >> > > -- > Marcus Denker -- http://marcusdenker.de

Aug. 30, 2011

Re: [Pharo-users] Serializing to/from Json

by Larry White

Wow. Thanks for all the replies. @Bernat. I am using the SCouchDB library, but will take a look at the other one. Thanks. @Sven. I'll also take a look at that Json library. Thank you. @Markus. It has to Json, for exactly the reason that @Davorin suggests. @Francois. I'm looking at Magritte as well, but it seems a bit overwhelming for a Smalltalk noob. I may give it a try on my next project. Apologies for the naivete of the original question. It wasn't 'til I tried writing my own that I realized (doh) that you can't write something like Gson in Java without augmenting the model with type information. I assume that's how Magritte does it, since it seems to be all about meta data. On Tue, Aug 30, 2011 at 5:30 AM, Bernat Romagosa < tibabenfortlapalanca(a)gmail.com> wrote: > Without having tried them, I see there are two CouchDB projects in > squeaksource, they may handle your needs: > > http://www.squeaksource.com/SCouchDB.html > http://www.squeaksource.com/CouchDB.html > > Cheers, > > > 2011/8/30 Sven Van Caekenberghe <sven(a)beta9.be> > >> Hi Larry, >> >> On 29 Aug 2011, at 21:27, Larry White wrote: >> >> > I've tried the JSON library bundled with SCouchDB and it seems to >> automatically handle simple objects (eg, where the inst vars reference >> Strings or Numbers), but not handle more complex objects. Also, I haven't >> seen anything that de-serializes from json. >> >> There is a JSON encoder/decoder in Seaside, it is pretty standalone, see >> this recent thread: >> >> http://forum.world.st/Standalone-JSON-Package-tp3759705p3759705.html >> >> This one works very well (I am using it all the time), but only handles >> standard JSON types (follows the spec). >> >> Now, JSON objects don't hold their type or class as Smalltalk (or Java >> objects) do, they are just Dictionaries. There is no automagic solution to >> this, apart from encoding the type/class as a property, but will most >> probably not be portable across languages (java.lang.Integer for Java, >> Integer for Smalltalk), one of the strengths of JSON. >> >> So you will have to write code to convert your Person (or whatever) >> objects to/from Dictionaries and use JSON. >> >> Sven >> >> >> >> > > > -- > Bernat Romagosa. >

Aug. 30, 2011

Re: [Pharo-users] Serializing to/from Json

by Bernat Romagosa

Without having tried them, I see there are two CouchDB projects in squeaksource, they may handle your needs: http://www.squeaksource.com/SCouchDB.html http://www.squeaksource.com/CouchDB.html Cheers, 2011/8/30 Sven Van Caekenberghe <sven(a)beta9.be> > Hi Larry, > > On 29 Aug 2011, at 21:27, Larry White wrote: > > > I've tried the JSON library bundled with SCouchDB and it seems to > automatically handle simple objects (eg, where the inst vars reference > Strings or Numbers), but not handle more complex objects. Also, I haven't > seen anything that de-serializes from json. > > There is a JSON encoder/decoder in Seaside, it is pretty standalone, see > this recent thread: > > http://forum.world.st/Standalone-JSON-Package-tp3759705p3759705.html > > This one works very well (I am using it all the time), but only handles > standard JSON types (follows the spec). > > Now, JSON objects don't hold their type or class as Smalltalk (or Java > objects) do, they are just Dictionaries. There is no automagic solution to > this, apart from encoding the type/class as a property, but will most > probably not be portable across languages (java.lang.Integer for Java, > Integer for Smalltalk), one of the strengths of JSON. > > So you will have to write code to convert your Person (or whatever) objects > to/from Dictionaries and use JSON. > > Sven > > > > -- Bernat Romagosa.

Aug. 30, 2011

Re: [Pharo-users] Serializing to/from Json

by Sven Van Caekenberghe

Hi Larry, On 29 Aug 2011, at 21:27, Larry White wrote: > I've tried the JSON library bundled with SCouchDB and it seems to automatically handle simple objects (eg, where the inst vars reference Strings or Numbers), but not handle more complex objects. Also, I haven't seen anything that de-serializes from json. There is a JSON encoder/decoder in Seaside, it is pretty standalone, see this recent thread: http://forum.world.st/Standalone-JSON-Package-tp3759705p3759705.html This one works very well (I am using it all the time), but only handles standard JSON types (follows the spec). Now, JSON objects don't hold their type or class as Smalltalk (or Java objects) do, they are just Dictionaries. There is no automagic solution to this, apart from encoding the type/class as a property, but will most probably not be portable across languages (java.lang.Integer for Java, Integer for Smalltalk), one of the strengths of JSON. So you will have to write code to convert your Person (or whatever) objects to/from Dictionaries and use JSON. Sven

Aug. 30, 2011