Difference between MySQL 4 and 5

Hi there
Was wondering if anyone knew the differences between MySQL 4 and 5? Are there any security differences?

Thanks

Security updates are still being released for mysql 4.0.x and 4.1.x. So if you want security you should update to the most recent point release for your version rather than to a whole new version. Logically one might assume older versions (with latest security updates) are more secure than newer versions as they have been around longer and are more tested. But don’t necessarily base your judgements on that - all versions receive security updates.

Other than that, new features in mysql 5 are described here
http://dev.mysql.com/doc/refman/5.0/en/mysql-5-0-nutshell.html

In summary, performance enhancement in specific situations, and new features.

When you use a database in your application, security is largely in your own hands, regardless of which database server you are using.

To put all this in a nutshell, MySQL 5 introduced following important features among others.

  1. Cursors
  2. Stored Procedures
  3. Triggers
  4. Views

Yes for every kind of detail about these as well as other features, refer the MySQL manual page cited by mmj.

You can also check following:
http://dev.mysql.com/doc/refman/5.0/en/roadmap.html

please see this thread where i list the difference between all the differences between the major versions of mysql: http://www.sitepoint.com/forums/showthread.php?t=408497