Need Help Writing SQL Trigger - sql

Question

Been trying to write this trigger but I can't really work it out..
What I need to do:
Delete an item from the item table but at the same time delete any questions which are associated with the item as well as any questionupdates associated with that question. These deleted records then need to be stored in archived tables with a time of deletion as well as the ID of the operator that deleted them.
A question may have several updates associated with it as may an item have many questions relating to it.
I've put all the schema in the SQL fiddle as it's a lot easier to work on in there but I'll put it in here if needed.
The link to the SQL fiddle:
http://sqlfiddle.com/#!1/1bb25
EDIT: Thought I might as well put it here..
Tables:
CREATE TABLE Operator
(
ID INTEGER NOT NULL PRIMARY KEY,
Name VARCHAR(40) NOT NULL
);
CREATE TABLE Item
(
ID INTEGER NOT NULL PRIMARY KEY,
Name VARCHAR(40) NOT NULL
);
CREATE TABLE Faq
(
ID INTEGER NOT NULL PRIMARY KEY,
Question VARCHAR(150) NOT NULL,
Answer VARCHAR(2500) NOT NULL,
ItemID INTEGER,
FOREIGN KEY (ItemID) REFERENCES Item(ID)
);
CREATE TABLE Customer
(
ID INTEGER NOT NULL PRIMARY KEY,
Name VARCHAR(20) NOT NULL,
Email VARCHAR(20) NOT NULL
);
CREATE TABLE Question
(
ID INTEGER NOT NULL PRIMARY KEY,
Problem VARCHAR(1000),
AskedTime TIMESTAMP NOT NULL,
CustomerID INTEGER NOT NULL,
ItemID INTEGER NOT NULL,
FOREIGN KEY (ItemID) REFERENCES Item(ID),
FOREIGN KEY (CustomerID) REFERENCES Customer(ID)
);
CREATE TABLE qUpdate
(
ID INTEGER NOT NULL PRIMARY KEY,
Message VARCHAR(1000) NOT NULL,
UpdateTime TIMESTAMP NOT NULL,
QuestionID INTEGER NOT NULL,
OperatorID INTEGER,
FOREIGN KEY (OperatorID) REFERENCES Operator(ID),
FOREIGN KEY (QuestionID) REFERENCES Question(ID)
);
-- Archive Tables
CREATE TABLE DeletedQuestion
(
ID INTEGER NOT NULL PRIMARY KEY,
Problem VARCHAR(1000),
AskedTime TIMESTAMP NOT NULL,
CustomerID INTEGER NOT NULL,
ItemID INTEGER NOT NULL
);
CREATE TABLE DeletedqUpdate
(
ID INTEGER NOT NULL PRIMARY KEY,
Message VARCHAR(1000) NOT NULL,
UpdateTime TIMESTAMP NOT NULL,
Question INTEGER NOT NULL
);
CREATE TABLE DeletedItem
(
ID INTEGER NOT NULL PRIMARY KEY,
Name VARCHAR(40) NOT NULL,
OperatorDeleteID INTEGER NOT NULL,
FOREIGN KEY (OperatorDeleteID) REFERENCES Operator(ID)
);
Some samples inserts for testing
--Product Inserts
INSERT INTO Item (ID, Name) VALUES (1, 'testitem1');
INSERT INTO Item (ID, Name) VALUES (2, 'testitem2');
--Operator Inserts
INSERT INTO Operator (ID, Name) VALUES (1, 'testname1');
INSERT INTO Operator (ID, Name) VALUES (2, 'testname2');
--Faq Inserts
INSERT INTO Faq (ID, Question, Answer, ItemID) VALUES (1, 'testq1', 'testa1', 1);
INSERT INTO Faq (ID, Question, Answer, ItemID) VALUES (2, 'testq2', 'testa2', 2);
-- Customer Inserts
INSERT INTO Customer (ID, Name, Email) VALUES (1, 'testcust1', 'testemail1');
INSERT INTO Customer (ID, Name, Email) VALUES (2, 'testcust2', 'testemail2');
-- Question Inserts
INSERT INTO Question (ID, Problem, AskedTime, CustomerID, ItemID) VALUES (1,'testproblem1','2012-03-14 09:30',1,1);
INSERT INTO Question (ID, Problem, AskedTime, CustomerID, ItemID) VALUES (2,'testproblem1','2012-07-14 09:30',2,1);
INSERT INTO qUpdate (ID, Message, UpdateTime, OperatorID, QuestionID) VALUES (1, 'test1','2012-05-14 09:30', 1, 1);
INSERT INTO qUpdate (ID, Message, UpdateTime, OperatorID, QuestionID) VALUES (2, 'test2','2012-08-14 09:30', 2, 1);

Answer 1

The first thing to do is to understand that in PostgreSQL, a CREATE TRIGGER statement binds a trigger function to one or more operations on a table, so let's start with the syntax of the function. You can write trigger functions in various scripting languages, but the most common is plpgsql. A simple function might look like this:
CREATE OR REPLACE FUNCTION Question_delete_trig_func()
RETURNS TRIGGER
LANGUAGE plpgsql
AS $$
BEGIN
INSERT INTO DeletedQuestion
SELECT OLD.*;
RETURN OLD;
END;
$$;
To run this after deletes:
CREATE TRIGGER Question_delete_trig
AFTER DELETE ON Question
FOR EACH ROW EXECUTE PROCEDURE Question_delete_trig_func();
That should be enough to get you started.
You should have a trigger like this for each table from which deleted rows should be saved. Then you need to determine how you will make the deletes happen. You could just define the appropriate foreign keys as ON DELETE CASCADE and let PostgreSQL do it for you.