Re: Table with 7000 columns?

On Tue, 30 Nov 2004 14:39:17 +0800, utkanbir wrote (in article <f6c90ebe.0411292239.42efe1f2_at_posting.google.com>):

> Hi ,
>
> This is related to datawarehouse , data mining . We are told that data
> mining tools such as spss or sas , need a large table which has lots
> of columns inside . Based on our project , out final table which will
> be used in data mining , has lots of computed values . The final
> number of columns of the table is 7800!(lots of calculated values)
> First of all , i dont see the reason of this requirement of the data
> mining tools. I will be appreciated if someone can clarify this: Why
> does a data mining tool need such a large table?
>
> The main issue is if i create table with 7800 columns inside ( in fact
> oracle only allows to create table with 1000 columns) , i believe it
> cant be queried.
> My basic calculation shows that the average row size of this table
> will be 160kb. , considering my db_block_size of 16kb. this means 10
> blocks for 1 row. (The table will have more than 10.000.000 rows) No
> matter how fast my disk subsystem is , i think the queries against
> this table will fail. So what can i do? May be I need a different
> type of storage technique for instance column based storage ( i heard
> that sysbase has this feature , dont know the details / purpose..)
> How can i solve such a problem? The database server really does not
> matter , it can be oracle,sqlserver , sybase,informix , etc... I will
> be appreciated if someone can help me abut the issue.
>
> Kind Regards,
> hope

you cannot possibly need a table with 7800 cols, not even 1000 cols what exactly are you "calculating" that requires that many cols?

show us an example and how the cols are going to be calculated.

steve Received on Wed Dec 01 2004 - 15:44:08 CST