Reading through the above you would be forgiven for wondering why this book focuses on the MySQL DBMS - the features it supports are very similar to features in other databases, and in some ways it actually misses out on things that larger DBMSs, such as Oracle, offers.
It is true that other databases support the full set of features, but they do so at the cost of speed. Most web databases have no need for functionality beyond storing and retrieving data, and by doing without them MySQL has been concentrated on being the fastest DBMS available. MySQL really is the ideal database for web databases, however it will expand into other areas more and more as the other features above get implemented.
If this was helpful, please take a moment to tell others about Hacking with PHP by tweeting about it!