Script for Time Dimension Table

Note - This blog post was updated on Nov. 14, 2012 with a new script.  This as been simplified a bit and includes half year.

One of the more common requests I get is a script for creating time dimension tables for Oracle OLAP. The following script will create a time dimension table for a standard calendar. It starts by creating a table with dimension members and labels. The second part of the script fills in end date and time span attributes. The section that creates end date and time span can be easily adapted for completing other calendars (e.g., fiscal) where the members have already been filled in.

--
-- Create time dimension table for a standard calendar year (day, month,
-- quarter, half year and year).
--
-- Drop table.
--
--DROP TABLE time_calendar_dim;
--
-- Create time dimension table for calendar year.
--
-- First day if the next day after TO_DATE('31/12/2010','DD/MM/YYYY').
-- Number of days is set in CONNECT BY level <= 365.
--
-- Values for end date and time span attributes are place holders. They need
-- to be filled in correctly later in this script.
--
CREATE TABLE time_calendar_dim AS
WITH base_calendar AS
  (SELECT CurrDate          AS Day_ID,
    1                       AS Day_Time_Span,
    CurrDate                AS Day_End_Date,
    TO_CHAR(CurrDate,'Day') AS Week_Day_Full,
    TO_CHAR(CurrDate,'DY')  AS Week_Day_Short,
    TO_NUMBER(TRIM(leading '0'
  FROM TO_CHAR(CurrDate,'D'))) AS Day_Num_of_Week,
    TO_NUMBER(TRIM(leading '0'
  FROM TO_CHAR(CurrDate,'DD'))) AS Day_Num_of_Month,
    TO_NUMBER(TRIM(leading '0'
  FROM TO_CHAR(CurrDate,'DDD'))) AS Day_Num_of_Year,
    UPPER(TO_CHAR(CurrDate,'Mon')
    || '-'
    || TO_CHAR(CurrDate,'YYYY')) AS Month_ID,
    TO_CHAR(CurrDate,'Mon')
    || ' '
    || TO_CHAR(CurrDate,'YYYY') AS Month_Short_Desc,
    RTRIM(TO_CHAR(CurrDate,'Month'))
    || ' '
    || TO_CHAR(CurrDate,'YYYY') AS Month_Long_Desc,
    TO_CHAR(CurrDate,'Mon')     AS Month_Short,
    TO_CHAR(CurrDate,'Month')   AS Month_Long,
    TO_NUMBER(TRIM(leading '0'
  FROM TO_CHAR(CurrDate,'MM'))) AS Month_Num_of_Year,
    'Q'
    || UPPER(TO_CHAR(CurrDate,'Q')
    || '-'
    || TO_CHAR(CurrDate,'YYYY'))     AS Quarter_ID,
    TO_NUMBER(TO_CHAR(CurrDate,'Q')) AS Quarter_Num_of_Year,
    CASE
      WHEN TO_NUMBER(TO_CHAR(CurrDate,'Q')) <= 2
      THEN 1
      ELSE 2
    END AS half_num_of_year,
    CASE
      WHEN TO_NUMBER(TO_CHAR(CurrDate,'Q')) <= 2
      THEN 'H'
        || 1
        || '-'
        || TO_CHAR(CurrDate,'YYYY')
      ELSE 'H'
        || 2
        || '-'
        || TO_CHAR(CurrDate,'YYYY')
    END                      AS half_of_year_id,
    TO_CHAR(CurrDate,'YYYY') AS Year_ID
  FROM
    (SELECT level n,
      -- Calendar starts at the day after this date.
      TO_DATE('31/12/2010','DD/MM/YYYY') + NUMTODSINTERVAL(level,'DAY') CurrDate
    FROM dual
      -- Change for the number of days to be added to the table.
      CONNECT BY level <= 365
    )
  )
SELECT day_id,
  day_time_span,
  day_end_date,
  week_day_full,
  week_day_short,
  day_num_of_week,
  day_num_of_month,
  day_num_of_year,
  month_id,
  COUNT(*) OVER (PARTITION BY month_id)    AS Month_Time_Span,
  MAX(day_id) OVER (PARTITION BY month_id) AS Month_End_Date,
  month_short_desc,
  month_long_desc,
  month_short,
  month_long,
  month_num_of_year,
  quarter_id,
  COUNT(*) OVER (PARTITION BY quarter_id)    AS Quarter_Time_Span,
  MAX(day_id) OVER (PARTITION BY quarter_id) AS Quarter_End_Date,
  quarter_num_of_year,
  half_num_of_year,
  half_of_year_id,
  COUNT(*) OVER (PARTITION BY half_of_year_id)    AS Half_Year_Time_Span,
  MAX(day_id) OVER (PARTITION BY half_of_year_id) AS Half_Year_End_Date,
  year_id,
  COUNT(*) OVER (PARTITION BY year_id)    AS Year_Time_Span,
  MAX(day_id) OVER (PARTITION BY year_id) AS Year_End_Date
FROM base_calendar
ORDER BY day_id;
);
--
COMMIT;