TIME Dimension - TIME_SPAN parameter value (constant or decrementing?)

Question

Hi all
For the the 'TIME_SPAN' parameter value in dimension of type 'TIME', should the value be constant for all members in a particular level or should the value decrement over time as the period progresses.
For example, for a TIME dimension having levels DAY > MONTH should the values for TIME_SPAN be:
DAY, DAY_END_DATE, DAY_TIME_SPAN, MONTH, MONTH_END_DATE, MONTH_TIME_SPAN
D01JAN2010, 01-01-2010, 1, M01_Y2010, 31-01-2010, 31
D02JAN2010, 02-01-2010, 1, M02_Y2010, 31-01-2010, 31
D03JAN2010, 03-01-2010, 1, M03_Y2010, 31-01-2010, 31
and so on...
or like below:
D01JAN2010, 01-01-2010, 1, M01_Y2010, 31-01-2010, 31
D02JAN2010, 02-01-2010, 1, M02_Y2010, 31-01-2010, 30
D03JAN2010, 03-01-2010, 1, M03_Y2010, 31-01-2010, 29
and so on...
Any assistance will be appreciated.
Cheers.

Answer 1

Here's a script that might be helpful to you. It fills in aggregate values for date and times span when you have existing days with date data type. If you have time periods shorter than a day, you might check out this post.
http://oracleolap.blogspot.com/2010/05/time-dimensions-with-hourly-time.html
CREATE TABLE time_dim
DAY_KEY DATE,
DAY_TIME_SPAN NUMBER,
MONTH_ID VARCHAR2(30),
MONTH_END_DATE DATE,
MONTH_TIME_SPAN NUMBER,
QUARTER_ID VARCHAR2(30),
QUARTER_END_DATE DATE,
QUARTER_TIME_SPAN NUMBER,
CALENDAR_YEAR_ID VARCHAR2(30),
YEAR_END_DATE DATE,
YEAR_TIME_SPAN NUMBER
-- Add rows for days. E.g.,
-- insert into time_dim (select distinct day_key from fact_view);
--UPDATE time_dim
--SET hour_time_span = round(1/24,5);
-- Add month members.
UPDATE time_dim SET month_id = TO_CHAR(day_key 'MON-YYYY');
UPDATE time_dim a
SET month_time_span =
(SELECT ts
FROM
(SELECT DISTINCT month_id,
SUM(day_time_span) AS ts
FROM time_dim
GROUP BY month_id
) b
WHERE a.month_id = b.month_id
UPDATE time_dim a
SET month_end_date =
(SELECT ed
FROM
(SELECT DISTINCT month_id,
MAX(day_key) AS ed
FROM time_dim
GROUP BY month_id
) b
WHERE a.month_id = b.month_id
-- Add Quarter members.
UPDATE time_dim SET quarter_id = TO_CHAR(day_key 'Q-YYYY');
UPDATE time_dim a
SET quarter_time_span =
(SELECT ts
FROM
(SELECT DISTINCT quarter_id,
SUM(day_time_span) AS ts
FROM time_dim
GROUP BY quarter_id
) b
WHERE a.quarter_id = b.quarter_id
UPDATE time_dim a
SET quarter_end_date =
(SELECT ed
FROM
(SELECT DISTINCT quarter_id,
MAX(day_key) AS ed
FROM time_dim
GROUP BY quarter_id
) b
WHERE a.quarter_id = b.quarter_id
-- Add Year members.
UPDATE time_dim SET month_id = TO_CHAR(day_key 'YYYY');
UPDATE time_dim a
SET year_time_span =
(SELECT ts
FROM
(SELECT DISTINCT year_id,
SUM(day_time_span) AS ts
FROM time_dim
GROUP BY year_id
) b
WHERE a.year_id = b.year_id
UPDATE time_dim a
SET year_end_date =
(SELECT ed
FROM
(SELECT DISTINCT year_id,
MAX(day_key) AS ed
FROM time_dim
GROUP BY year_id
) b
WHERE a.year_id = b.year_id
;