Modify a query in a view to be dynamic

Question

Hello
The following view's Query outputs the months of a financial year i got it with the assistance of a member here Blueshadow.
Well,i put it in a view to select month_code and month_desc in a report.
CREATE OR REPLACE VIEW FINANCIAL_YEAR_MONTHS
(MONTH_CODE, MONTH_DESC)
AS
select  to_char(add_months(FROM_DATE,rn-1),'MM/YYYY') as financial_month,
month_desc
from (select * from cde_fin_year where fin_year_code = *2007*)
cross join (select rownum rn from dual connect by rownum <= 12) x
join cde_month on (cde_month.month_code = to_char(add_months(FROM_DATE,x.rn-1),'MM'))
order by x.rn;All i want to do is to make this statment dynamic not only specified to year 2007 but any year to be entered so i want to change this line to accept any parameter as follows :
from (select * from cde_fin_year where fin_year_code = *2007*)Regards,
Abdetu..

Answer 1

Abdetu wrote:
All i want to do is to make this statment dynamic not only specified to year 2007 but any year to be entered so i want to change this line to accept any parameter as follows :Oracle does not have ability to create dynamic views. What Satyaki De is suggesting does not create a dynamic view but rather allows to create a view dinamically. View itself is static. That solution simply prompts you what year to use while creating the view. When created, view will ONLY return the months of the financial year entered while creating the view.+* Normally, one would create view without imposing year selection and adding year to view select list:
CREATE OR REPLACE VIEW FINANCIAL_YEAR_MONTHS
(MONTH_CODE, MONTH_DESC,fin_year_code)
AS
select  to_char(add_months(FROM_DATE,rn-1),'MM/YYYY') as financial_month,
month_desc
from (select * from cde_fin_year)
cross join (select rownum rn from dual connect by rownum <= 12) x
join cde_month on (cde_month.month_code = to_char(add_months(FROM_DATE,x.rn-1),'MM'))
order by x.rn;and use specific year when selecting from the view:
select * from FINANCIAL_YEAR_MONTHS where fin_year_code = whatever-year-you-need;You will have to check how it affects preformance. If optimizer will realize to push down condition fin_year_code = whatever-year-you-need, you should be OK. Otherwise view will calculate data for all financial years and only then filter that data with fin_year_code = whatever-year-you-need. Another solution could be PL/SQL package:
CREATE OR REPLACE
  PACKAGE PKG_FINANCIAL_YEAR
    IS
      PROCEDURE SET(
                    p_financial_year NUMBER
      FUNCTION GET
        RETURN NUMBER
        DETERMINISTIC;
END;
CREATE OR REPLACE
  PACKAGE BODY PKG_FINANCIAL_YEAR
    IS
      g_financial_year NUMBER;
      PROCEDURE SET(
                    p_financial_year NUMBER
        IS
        BEGIN
            g_financial_year := p_financial_year;
        END;
      FUNCTION GET
        RETURN NUMBER
        DETERMINISTIC
        IS
        BEGIN
            RETURN g_financial_year;
        END;
END;
CREATE OR REPLACE VIEW FINANCIAL_YEAR_MONTHS
(MONTH_CODE, MONTH_DESC)
AS
select  to_char(add_months(FROM_DATE,rn-1),'MM/YYYY') as financial_month,
month_desc
from (select * from cde_fin_year where fin_year_code = PKG_FINANCIAL_YEAR.GET)
cross join (select rownum rn from dual connect by rownum <= 12) x
join cde_month on (cde_month.month_code = to_char(add_months(FROM_DATE,x.rn-1),'MM'))
order by x.rn;Now, you would have to set/change financial year before selecting from the view:
PKG_FINANCIAL_YEAR.SET(2007)
/Keep in mind, even though PKG_FINANCIAL_YEAR.GET is declared as deterministic, there is no guarantee it will be called once, so it might be slight performance degradatation. Similar can be achieved by creating GTT:
CREATE GLOBAL TEMPORARY TABLE GTT_FINANCIAL_YEAR(FIN_YEAR NUMBER);
CREATE OR REPLACE VIEW FINANCIAL_YEAR_MONTHS
(MONTH_CODE, MONTH_DESC)
AS
select  to_char(add_months(FROM_DATE,rn-1),'MM/YYYY') as financial_month,
month_desc
from (select * from cde_fin_year,GTT_FINANCIAL_YEAR where fin_year_code = FIN_YEAR)
cross join (select rownum rn from dual connect by rownum <= 12) x
join cde_month on (cde_month.month_code = to_char(add_months(FROM_DATE,x.rn-1),'MM'))
order by x.rn;Same way, you would have to set/change financial year before selecting from the view:
DELETE GTT_FINANCIAL_YEAR
INSERT GTT_FINANCIAL_YEAR
  VALUES(2007)
/SY.