I am not too familiar with database triggers and/or views. I am currently using PostgreSQL and HSQL, even though the database is not too important. I am just wondering if any database offers something like this:
I have an (example) table like this:
CREATE TABLE DUMMY_TABLE (ID INTEGER, NUMBER INTEGER);
I created a view like this:
CREATE VIEW DUMMY_VIEW AS SELECT * FROM DUMMY_TABLE WHERE NUMBER > 5;
I insert a couple of entities:
INSERT INTO DUMMY_TABLE VALUES(1,2);
INSERT INTO DUMMY_TABLE VALUES(1,10);
So of course, the DUMMY_VIEW only contains VALUES(1,10) when I call:
SELECT * FROM DUMMY_VIEW;
So now what I want to do is add a trigger to the DUMMY_VIEW that is called whenever an entity is inserted that has NUMBER > 5.
I have tried adding triggers directly to the DUMMY_VIEW in both HSQL and PostgreSQL but they say that triggers cannot be added to views.
Is this (or a functionally similar solution) possible?
It should be noted that PostgreSQL 9.1+ supports triggers on views. See WAITING FOR 9.1 – TRIGGERS ON VIEWS for a brief look at this.