Kimball Templates

When using the Kimball templates for designing Dimension tables, there are 3 columns I have questions about.
Isn't the RowStartDate and RowEndDate the way to manage historical values? If so; why is the need for RowIsCurrent?
In my example dimension below, it is capturing slow changing phone numbers. Is the RowIsCurrent just a better faster way to find the most current records instead of querying the most recent dates?
Client Name: Phone Number: RowStartDate: RowEndDate; RowIsCurrent
Joe Momma (360) 533-3232 2/1/2005 2/18/2005 N
Greg Olson (360) 822-2323 3/4/2005 12/31/9999 Y
Joe Momma (360) 331-8800 2/18/2005 12/31/9999 Y
On Apr 12, 7:42 pm, "Joe" <hortoris...@.gmail.dot.com> wrote:
> When using the Kimball templates for designing Dimension tables, there are 3 columns I have questions about.
> Isn't the RowStartDate and RowEndDate the way to manage historical values? If so; why is the need for RowIsCurrent?
> In my example dimension below, it is capturing slow changing phone numbers. Is the RowIsCurrent just a better faster way to find the most current records instead of querying the most recent dates?
> Client Name: Phone Number: RowStartDate: RowEndDate; RowIsCurrent
> Joe Momma (360) 533-3232 2/1/2005 2/18/2005 N
> Greg Olson (360) 822-2323 3/4/2005 12/31/9999 Y
> Joe Momma (360) 331-8800 2/18/2005 12/31/9999 Y
Joe,
if you think about the sql require to get 'the most recent record'
using a date versus using a flag you will see why we have the
flags....if you don't want to just accept that this is how it is
done...write the sql and check it out.
Best Regards
Peter
www.peternolan.com