How to not repeat fields

[Deckard]

Hi,

How do i dreate a table, let's say:

CREATE TABLE wl_articles(wl_articles_id INT NOT NULL AUTO_INCREMENT
PRIMARY KEY, title TEXT NOT NULL,
         main TEXT NOT NULL, extended TEXT NOT NULL, permalink
VARCHAR(255) NOT NULL, date DATE NOT NULL, ip VARCHAR(15), user_agent
VARCHAR(50), status INTEGER NOT NULL,
                 password VARCHAR(32) NOT NULL) TYPE=MyISAM;

without allowing INSERTs to repeat rows based on certain fields, for
example, "main" and "status" ?

Any help would be appreciated.

Warm Regards,
Deckard