MySQL 4.1, the following development release
Internally, through a new .frm file format for table definitions, MySQL 4.0 lays the foundation for the new features of MySQL 4.1, such as nested subqueries, stored procedures, and foreign key integrity rules, which form the top of the wish list for many of our customers. Along with those, we will also include simpler additions, such as multi-table UPDATE statements.
http://www.mysql.com/products/mysql-4.0/index.html
faudra encore attendre un peu