You can as= sign a value you are going to need when after querying to the docid. The pr= oblem with this schema is that if there are not many type:c_bot_code combin= ations, there will be many columns under each key in this CF. If a combinat= ion has much much more columns than others, hot spot problem may arise.

On Tue, Mar 1, 2011 at 11:39 PM, Vodnok <vodnok@gmail.com> wrote:

Hi,

Totaly newbi= e on Cassandra (with phpcassa) with big background on relationned database,= i'm would like to use Cassandra for a trivial case. So i'm on it s= ince 3 days. Sorry for my stupid question. I'm pretty sure i'm wron= g but i want to learn so i'm here

I would like your advise on a design for= cassandra.

Case:

<= div>

- Users created Docs and can share docs with friends

- Users can read and share docs of their friends with other friends

- Docs can be of different type [text;picture;video;etc]

= - Docs can be taggued

Typical queries :

- Doc relati= ve to tag

- Doc relative to mutiple tags

- Doc readed b= y user x

- Doc relative to tag and ratio readed_shared greater th= an x (see design)

- All doc of type=3D'IMG' favorized by my friend

- A= ll doc of type=3D'BOT' and c_bot_code=3D'ABC'

- A= ll doc of type=3D'BOT' favorized by my friend relative (tag) with &= #39;fire' and 'belgium' ?

Design :

docs // all docs

{

=A0=A0 =A0= =91123456=92: //id_docs

=A0=A0 =A0{

=A0=A0 =A0 =A0 =A0= =91t_info=92:=A0

{<= /div>

'c_type':'B= OT'

'b_del= ':'y'

= 'b_publish':'y'

}

't_info_type':

{

'l_title':'= Hello World!'

= 'c_bot_code':'ABC'

}

't_read_user' : //read by user x=

{

//time + id_user

<= div> '123456789_123':= '123'

'= ;123456789_155':'155'

}

't_shared_user' : //share by use= r x

{

//time + id_user

<= div> '123456789_123':= '123'

'= ;123456789_155':'155'

}

't_tags'

{

'fire':'fir= e'

'belgiu= m':'belgium'

<= /span>}

't_stats'

<= div> {

'n_readed':'60'

'n_shared':'= ;6'

'n_rat= io_readed_shared':'0.1' =

}

tags_docs // all tag linked to docs

{

'fire'= ;://tag

{

= //creation_time + id_docs

'456789_123456':=

{

'id_doc':'123456'<= /div>

'time':'456= 789'

}

'456789_223456':= 9;223456':

{

'id_doc':'123456'

'time':'456= 789'

}

'456789_323456':'223456'= :

{

'id_doc':'1= 23456'

'ti= me':'456789'

<= /span>}

}

'belgium':

{

...

} <= /span>

}

users // all users

{

=A0=A0 =A0=91123=92: //id_user

=A0=A0 =A0{

=A0=A0 =A0 = =A0 =A0=91t_info=92:=A0

{

l_name:'Boris'<= /div>

c_lang=3D'fr&#= 39;

= }

't_readed_docs':=

{

//time + id_doc

'123456789_123456&#= 39;:'123456'

'123458789_136456':'136456'

}

't_shared_docs':

{

//time + id_doc

'123456789_123456'= ;:'123456'

'123458789_136456':'136456'

}

users_docs // all action by = users on docs

{

=A0=A0 =A0=91123_123456=92: // id_user = + id_doc

=A0=A0 =A0{

'id_doc':'123456'

'id_user':'1= 23'

'd_read= ed':'20110301'

= 'd_shared':'20110301'

}

<= br>

user_friends_act // all activity of user frien= ds

{

=A0=A0 =A0=91123=92:// id_user

=A0=A0 =A0{

't_= readed_docs': //all docs readed by my friends

{

'223456_224_123456': // time + id_friend + id_docs

{

'id_friend':'224'

'id_docs':= 9;123456'

'time':'22= 3456'

'c_= type=3D'BOT'

}

't_shared_docs': //all docs shared by my friends<= /div>

{

'223456_224_123456': // time + = id_friend + id_docs

{

'id_friend':&#= 39;224'

'= id_docs':'123456'

'time':'22= 3456'

'c_= type=3D'BOT'

}

I know that c= ertain queries are not possible for now like : - All doc of type=3D'BOT= ' favorized by my friend relative (tag) with 'fire' and 'be= lgium' ?

What do you think ?

Thank you,

Vodnok,

(Please remember= i'm on cassandra since 3 days)

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