Re: design question
From: Ana C. Dent <anacedent_at_hotmail.com>
Date: Sun, 07 Sep 2008 19:32:36 GMT
Message-ID: <Xns9B127F97A990anacedenthotmailcom@69.16.185.250>
>
> A table with lets say 100 columns and 90 % NULLs in each row is no
> problem for the database performance and storage?
>
>
> OK, one could change A in a way that the values are stored natively:
>
> create table ObjectProperty (ID numeric(10), ObjectID numeric(10),
> Fieldname varchar2(50), FieldvalueV varchar2(4000), FieldvalueN
> numeric(30,2), FieldvalueD date);
>
>
> So the question is basicly sould I use one row per value (A) or one
> row per object (B)?
>
> I think B is better for the database but A is more flexible if new
> object types have to be stored.
>
>
>
>
Date: Sun, 07 Sep 2008 19:32:36 GMT
Message-ID: <Xns9B127F97A990anacedenthotmailcom@69.16.185.250>
"Chris Seidel" <cseidel_at_arcor.de> wrote in
news:48c3bc5c$0$3548$9b4e6d93_at_newsspool3.arcor-online.net:
> DA Morgan wrote:
>
>> Most things have NULL columns ... what's the issue?
>
> A table with lets say 100 columns and 90 % NULLs in each row is no
> problem for the database performance and storage?
>
>> If you don't store numbers as numbers you can not do math. If you do >> not store dates as dates you can not do date math. Storing everything >> as strings made sense on mainframes 20 years ago. It has no place in >> a modern RDBMS.
>
> OK, one could change A in a way that the values are stored natively:
>
> create table ObjectProperty (ID numeric(10), ObjectID numeric(10),
> Fieldname varchar2(50), FieldvalueV varchar2(4000), FieldvalueN
> numeric(30,2), FieldvalueD date);
>
>
> So the question is basicly sould I use one row per value (A) or one
> row per object (B)?
>
> I think B is better for the database but A is more flexible if new
> object types have to be stored.
>
>
>
>
The BEST solution is to design the tables to conform to Third Normal Form Received on Sun Sep 07 2008 - 14:32:36 CDT