2.txt

This complete matlab for neural network

发信人: yaomc (白头翁&山东大汉), 信区: DataMining
标  题: [合集]国内有没有人做过Olap analysis engine?
发信站: 南京大学小百合站 (Fri Apr  5 12:54:52 2002), 站内信件

sn (小龙) 于Sat Mar 16 19:36:41 2002提到：

有谁知道这个方面的情况吗？
产品或者科研项目？


coffeemart (构思中) 于Sun Mar 17 11:32:46 2002)
提到：

不知道这个东东的主要用途和技术路线是什么呢？


sn (小龙) 于Sun Mar 17 23:45:46 2002提到：

就是on line analysis process啦 ,
可以在关系数据库上构建以支持多维模式的查询，
也可以直接以多维模式存储数据。


coffeemart (构思中) 于Tue Mar 19 10:50:39 2002)
提到：

哦,那我做过,
满足你的第一条,
我的理解就是以网格表或交叉表的形式将各个dimension以及measure展示出来.
第二条不是太清楚,以多维模式存储数据不就是将fact table,dimension table存在关系表
里么,当然也可以存在一个大表里,那样查询起来就不要连表啦.
不时是否还有其他深意?


fervvac (高远) 于Wed Mar 20 08:37:19 2002提到：

His two sentences covers two architectural choices for an OLAP engine: the
ROLAP and MOLAP approaches.

By storing the fact table or the cube in MOLAP format, it means data are 
treated as multidimensional points and the table (relation) is treated as
multidimensional array.

Both ROLAP and MOLAP implementation have some trickly places and not that 
straightforward, :p. For example, I am still wondering if there are any
tricks to enable the MOLAP approach to scale up, for example, 10 dim with 1000
cardinalities.



sn (小龙) 于Wed Mar 20 11:47:30 2002提到：

你做过的是使用现成的olap analysis engine做数据的展现工作，
比如你用oracle 的olap api或bibean,或用sql server的olap services, 还有很多＃，
我的意思是做一个olap analysis engine.



sn (小龙) 于Wed Mar 20 11:57:15 2002提到：

I am in a corporation, my aim is to build a system that can be used in my 
project implementtation, you know that Olap server is expensive, and I often 
do some small project, the customer don't want to spend that much, but they 
want to own the olap analysis. 
So I want to do an olap analysis engine , which I will store  meta data in re
lational
database, and access data over OLE DB interface, and I don't want to organize
 data
myself, it 's the matter of relational db, and of course customer should buy 
a relational database at least.
Do you think it feasible?



fervvac (高远) 于Wed Mar 20 12:46:37 2002提到：

I've got your motivation. Here are some rough thoughts that came to my 
mind immediately:
1) Why not leverage on existing OLAP engines? You mentioned the customers
   need to buy a RDBMS. If they use Windows and buy MS SQL Server, the OLAP
   part is already integrated inside.
   Of course, this argument can be easily defeated, :p

2) ROLAP engines usually employs special technologies to accelerate query 
   processing, such as bitmap index, star-join, etc., apart from data cube and
    materialized view. Efficiency will be compromised if those parts are
   missing or done exterior to the DBMS kernel.
   Of course, if the data volume is small, that's not a big deal.

3) So I guess it might be practical only if the data is not big and customers
   are poor (, :p). My suggestion is that you might need to do some
   proessing on the client side to avoid too much data transfer over the
   network.



sn (小龙) 于Wed Mar 20 19:32:40 2002提到：

Thanks for your advice.
There are many OLAP implementation and oriention, like Oracle's JOLAP,
microsoft's xml analysis, and other implementation, all accomodating a 
well-wrapped programming component and a client tool which is easy to use 
and owns a nice user interface.

I just want to build one for my project implementation, it may be fit for the 
small or middle company which want to own olap analysis and don't want to pay 
too much for it.
And it's fun to build a Olap analysis engine.

I will take care of the data transfer betwwen the client and the server, than
k you.



coffeemart (构思中) 于Fri Mar 22 16:16:01 2002)
提到：

我做的东西没有用过任何现成的东西,已经申请了软件著作权.虽然很多效率上的问题没有
得到很好的解决,但是也实施了十余家企业.
不知道你的推断是如何得出的.


sn (小龙) 于Mon Mar 25 11:38:43 2002提到：

我一直把这个工作分成数据的展现和多维模型的构造管理两个方面。前一个
方面是对结果数据以多种形式展现；后一个方面是组织数据，提供出一个逻辑的
多维模型，提供一个以维和度量的角度进行查询的接口。
所以我以为你做了第一个方面的工作。
看来你很早就做了这个东东，pfpf, 
还有十几家的成功案例，太好啦。