Hard trigger/constraints making

Question

I'm new to database and I have a question about a table with triggers or maybe a check constraint. I'm using SQL Server Mangagement studio.

I have the following table:

create table item(
    startprice        char(5)          not null,
    description       char(22)         not null,
    start_date        char(10)         not null,
    end_date          char(10)         not null,
    indicator         char(3)          not null

);

What I'm trying to make is this trigger/constraint rule: indicator will get "no" if system date is earlier than start_date and end_date, and "yes" if system date is after start_date.

Answer 1

This is simple you have to use trigger with before insert option -

Following trigger is good to go in Oracle DB -

CREATE OR REPLACE TRIGGER  item_insert_indicator 
BEFORE DELETE ON item 
For each row 
begin
if  :New.start_date > sysdate and :new.end_date > sysdate then 
   :New.indicator := 'no';
elsif :New.start_date < sysdate
   :New.indicator := 'yes';
end if;
end;

This is just for your reference. for your database you can change keywords accordingly.