First off, MySQL 4.0 supports views. (I'm wrong here.) MySQL 5.0 supports stored procedures, triggers and updateable views. As MySQL 5.0 is going to be released any day now, that canard is gone.

As for why you would use each feature, here's a quick primer:

• Triggers - these are used to do something whenever something else happens. Generally, they're used for maintaining data integrity with something outside the database or for some sort of referential integrity that standard foreign keys cannot do. My opinion is that if you are depending on them, you either don't trust your programmers or you build it wrong.
• Stored Procedures - these are little programs in your database. They're very useful when doing lots and lots of crazy stuff that's DB specific. I've used them and they're pretty nice, especially when you have multiple apps in multiple languages hitting the same database. Frankly, I don't work on those kinds of things anymore, so I don't use them.
• Views - These are great. Often, you have a table with a lot of information, but some of it is sensitive. So, you provide a view for those users who aren't allowed to see the whole thing. This is useful for applications, as well. If you can limit what an app is allowed to do, you limit what the attacker who cracked your app can do.

  Also, they're great for frequent joins. Let's say you have a join of three tables that you do on a regular basis. By providing a view for that join, you can reduce the query time because the DB will keep that resultset around as a temporary table.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.