Comparing a time period and a date via trigger....

Question

Hi ,
There are among others three tables....
Table material
   material_code number
   onomasia   varchar2(50)
   guarantee_end_date date
Table supplier_contract
     contract_code number
     start_date date
     end_date date
    supplier number(5)
Table supplier_contract_material
      contract_code number
      material_code numberThe table material , for each material contains the guarantee_end_date , whereas the other two contain info about the materials that should be replaced/fixed/ e.t.c by the supplier in the specific time period (start_date - end_date).
The thing that has to be done is there have not be any overlap of the dates.... In other words , when a material is bought then this is covered for replacement by the end of the date (guarantee_end_date in the first table). After this date there should be contract with the supplier for this material for a specific period (start_date - end_date , in the second table).
I want to secure the database that when the end_user tries to update this time_period(start_date - end_date) before or between the guarantee_end_date ("when i say between the guarantee_end_date " , i mean the condition guarantee_end_date between start_date and end_date is not acceptable) then an alert would be raised ....
So , I wrote the following trigger:
create or replace trigger trg_check_eggisi
before update on supplier_contract
for each row
declare
guarantee_end_date_var date;
begin
   begin
     select guarantee_end_date 
       into guarantee_end_date_var
       from material a, supplier_contract_material b
      where a.material_code=b.material_code
       and b.contract_code=:new.contract_code;
     exception
      when no_data_found
       then return;
    end;
   if guarantee_end_date_var>:new.guarantee_end_date_var
     then
     raise_application_error(-20021,'NOT_APPLICABLE');
   end if;   
end;The problem is that the error ORA-01422 is raised ... because more than 1 material may be contained in the specific contract....
Do you have any idea...????
many thanks ,
Simon

Answer 1

Hi  John,
As you want to  display the planned value of Depreciation for future years,
since this is not possible you can display the planned values only for that year and that too for subsequent periods,  you  will  see  the Yellow icon stating it is planned which is not yet posted in the posted value Tab,
Since if  you  want to display planned values for future year you have to  post Depreciation for subsequent period and close the fiscal year and again same procedure follows....
Regards,
Imran M Arab