CouchDB model Problem

[Luis Carlos Junges <lu...@gmail.com>]

Hi,

I would like to use couchdb for a project but i am unsure how to model it.
Basically i will have to store products and theirs respectives prices from
several  stores. So, for a product product1, for example, i will have a
price p1 for store1, a price p2 for store 2 and so on...Considering that
those prices will be updated automatically, i was thinking in something like
this:

A document for the product with all information about it with id equal to
the product reference number
example:

id:product1
name: Product 1


A document with the price and store id
id:89923848298398989d9fsd
revision:1
store:45
price:5.67
refcode:product1
updated: timestamp here


id:8992384829832938495298345
revision:3
store:46
price:3.67
refcode:product1
updated: timestamp here


My idea is that each store will update their own prices. Now the problem i
am no sure how to solve is that i can have multiple price documents with
differents ids (see example below) for the same store (a database
inconsistency). Could i use mapreduce to collect all the price documents for
a specific product  and get only the latest one based on the time is
updated. If so, how can i do that? i mean, how would be the map and reduce
function? I would also like to delete the old ones.



id:8992384829832938495298345
revision:1
store:46
price:3.67
refcode:product1
updated timestamp here


id:92839198234
revision:1
store:46
price:6.23
refcode:product1
updated timestamp here


I would appreciate any help

-- 
"A realidade de cada lugar e de cada época é uma alucinação coletiva."


Bloom, Howard

Re: CouchDB model Problem

[Anand Chitipothu <an...@gmail.com>]

2010/11/12 Luis Carlos Junges <lu...@gmail.com>:
> Hi,
>
> I would like to use couchdb for a project but i am unsure how to model it.
> Basically i will have to store products and theirs respectives prices from
> several  stores. So, for a product product1, for example, i will have a
> price p1 for store1, a price p2 for store 2 and so on...Considering that
> those prices will be updated automatically, i was thinking in something like
> this:
>
> A document for the product with all information about it with id equal to
> the product reference number
> example:
>
> id:product1
> name: Product 1
>
>
> A document with the price and store id
> id:89923848298398989d9fsd
> revision:1
> store:45
> price:5.67
> refcode:product1
> updated: timestamp here
>
>
> id:8992384829832938495298345
> revision:3
> store:46
> price:3.67
> refcode:product1
> updated: timestamp here
>
>
> My idea is that each store will update their own prices. Now the problem i
> am no sure how to solve is that i can have multiple price documents with
> differents ids (see example below) for the same store (a database
> inconsistency). Could i use mapreduce to collect all the price documents for
> a specific product  and get only the latest one based on the time is
> updated. If so, how can i do that? i mean, how would be the map and reduce
> function? I would also like to delete the old ones.
>
>
>
> id:8992384829832938495298345
> revision:1
> store:46
> price:3.67
> refcode:product1
> updated timestamp here
>
>
> id:92839198234
> revision:1
> store:46
> price:6.23
> refcode:product1
> updated timestamp here
>
>
> I would appreciate any help

How about using "$product-$store" as the _id for the document. In the
above example, _id will be "product1-46". This will make sure that
there are no duplicate price documents.

Anand