Re: Before insert trigger code

Hi Ranganath

For your case you can try to create trigger something like this (just example):

create or replace trigger <trigger name> before insert on <table name> for each row
DECLARE
row_count NUMBER;
BEGIN
SELECT count(*) INTO row_count from <table name> WHERE :new.start_dt BETWEEN start_dt AND expiry_dt OR
:new.expiry_dt BETWEEN start_dt AND expiry_dt; IF row_count>0 THEN

     dbms_output.put_line('Rejected by conditions '); ELSE
    dbms_output.put_line('Approved by conditions '); END IF;
END;
/

This trigger returns resulting message (for example) and executing COMMIT or ROLLBACK is up to you.

Regards

  Michael Malyk
  Oracle Programmer
  Toronto,Canada

RanganathK_at_lgcommerznow.com wrote:

> Dear all,
>
> I have a table by name image_master whose structure is as below:
>
> IMAGE_NAME NOT NULL
> VARCHAR2(60)
> TYPE NOT NULL
> CHAR(1)
> START_DT NOT NULL
> VARCHAR2(8)
> EXPIRY_DT
> VARCHAR2(8)
> IMAGE_DESC
> VARCHAR2(600)
> CREATE_DT
> VARCHAR2(8)
> MODIFY_DT
> VARCHAR2(8)
>
> The dates are entered in the form 'yyyymmdd'. All the dates have been
> assigned the datatype as varchar2(8) instead of date for a specific reason.
> I would like to create a before insert trigger on the table so that the
> user cannot insert a record if the start_dt and expiry_dt overlap the
> existing start_dt and expiry_dt in the existing records. For example, if
> there is a record whose start_dt is 20001126 and end_dt is 20001128 then
> the user is not allowed to have start_dt and end_dt between 26th and 28th
> November, 2000 (both dates inclusive). His start_dt and end_dt can be any
> dates apart from 26th, 27th and 28th November. How do I implement this
> using SQL or PL/SQL? Is there any other way out apart from creating a
> before insert trigger? I hope I am clear. Any help in this regard will
> be highly appreciated.
>
> TIA and regards,
>
> Ranganath
>
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>
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Received on Tue Nov 28 2000 - 14:09:19 CST