[wdmmg-discuss] RFC: Web OLAP API

Tue Aug 31 18:43:42 UTC 2010

Welcome Stefan, and thanks for posting.

On 26 August 2010 16:26, Stefan Urbanek <stefan at agentfarms.net> wrote:
[...]
> provides simple functionality for OLAP and multidimensional data cubes,
> inspired by Oracle tools.  By simple I mean: only multidimensional
> abstraction of relational data through logical data model, no precomputed
> cubes, no multidimensional data storage, no materialized views. Not yet :-)
>
> The logical model is based on snowflake schema [2].
> I've created a draft document of proposed Web OLAP API, that we are
> planning (and partially using for some URLs):
>
> http://bit.ly/bTnBoP

Great document Stefan! We too have been thinking about (and moving
towards) an OLAP type model, especially in the aggregate API.

At present there is a 'Transaction' table which is like the Fact table
in normal OLAP. This contains the spending amounts. We then have keys
(fields) with associated values. These values may either be single
strings or objects with additional metadata. (See [1] for more info).

[1]: <http://wiki.okfn.org/p/Where_Does_My_Money_Go/Store>

In terms of the API (<http://data.wheredoesmymoneygo.org/api>) we have
a standard REST interface at providing access to 'keys' (fields) and
individual transactions (facts):

/api/rest - <http://data.wheredoesmymoneygo.org/api/rest>

A search api providing for search across transactions:

/api/search - based on solr so exposes solr type query api

And an aggregate api which is what is most like OLAP:

/api/aggregate - <http://data.wheredoesmymoneygo.org/api>

For details of aggregate see the documentation page.

It seems there are some big similarities with your proposal and there
might be some significant advantages in converging towards something
that is fairly standardized. Take a look at the current WDMMG api and
let me know your thoughts.

Regards,

Rufus

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