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Home > Archive > MS SQL Data Warehousing > July 2005 > Should I use a new Dimension or not?
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Should I use a new Dimension or not?
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| marcmc 2005-05-23, 3:23 am |
| I have about 16 new columns I am bringing into the datawarehouse from an
AS400 system. Getting them in is no problem. I need to 'massage' these
through the warehouse in either an existing dimension or a new one. I am
toying with the idea of a new one in order to be able to trace directly if
there is a bug/problem as the 'regular' dimension used is very very complex.
My idea is to get the info in and get vehicle information to a fact table
dynamically. This vehicle dimension builds a number of surrogate tables for
vehicle attributes such as fuel, type, etc. I am taking in mainly flags of
yes and no as the new attributes. I intended on writing a
sp_dim_vehicle_attri
b dimension building vehicle codes that will link back to
my fact table from surrogates and lookups.
I am slightly confused as to what a surrogate table is actually used for. I
have read alot about them but it still aint gelling. I want to investigate
further the existing dimension and am thinking I might use it instead as I am
fearful of the new dimension become a bit messy inside the current model.
Any input greatly appreciated.
Marc.
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| Mumtaz Zaheer 2005-07-20, 3:23 am |
| Hi,
Before anyone can give you a suggestion, some more information would be
handy.
You have been thinking about technical problems you would face by adding
those new attributes in existing vehicle dimension.
By the way, what Facts do you have in FACT table?
Secondly, why is your current dimension is so complex? I mean, how do you
say it is complex? Because of hirerachies or anything else?
I believe you must have already reached a decision, do share with us what
was that and its advantage over other solutions.
Surrogates Keys, they are primary to remove dependecy from Natural keys at
source system.
Regards,
..Mumtaz
"marcmc" <marcmc@discussions.microsoft.com> wrote in message
news:24E3AAFD-34CD-40E9-B4F9- AB8C6E4C9F5C@microso
ft.com...
> I have about 16 new columns I am bringing into the datawarehouse from an
> AS400 system. Getting them in is no problem. I need to 'massage' these
> through the warehouse in either an existing dimension or a new one. I am
> toying with the idea of a new one in order to be able to trace directly if
> there is a bug/problem as the 'regular' dimension used is very very
complex.
>
> My idea is to get the info in and get vehicle information to a fact table
> dynamically. This vehicle dimension builds a number of surrogate tables
for
> vehicle attributes such as fuel, type, etc. I am taking in mainly flags of
> yes and no as the new attributes. I intended on writing a
> sp_dim_vehicle_attri
b dimension building vehicle codes that will link back
to
> my fact table from surrogates and lookups.
>
> I am slightly confused as to what a surrogate table is actually used for.
I
> have read alot about them but it still aint gelling. I want to investigate
> further the existing dimension and am thinking I might use it instead as I
am
> fearful of the new dimension become a bit messy inside the current model.
>
> Any input greatly appreciated.
>
> Marc.
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