Hello. I have a table and one of the field is set as timestamp and for default it has the current timestamp and is set as not null but when i save it, it doesnt put the current timestamp but puts "NULL", anybody has any idea why?

--Table: tickets

--DROP TABLE IF EXISTS tickets;

CREATE TABLE tickets (
ticket_id int AUTO_INCREMENT NOT NULL,
ip_address varchar(20),
host_name varchar(120),
operating_system varchar(200),
contactname varchar(200),
`subject` varchar(200),
category varchar(45),
priority varchar(20),
ticket_status int NOT NULL,
assigned_to varchar(30),
real_priority varchar(20),
extension varchar(10),
ticket_date timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
/* Keys */
PRIMARY KEY (ticket_id)
) ENGINE = InnoDB;

CREATE UNIQUE INDEX ticket_id_UNIQUE
ON tickets
(ticket_id);