I just saw an interesting post in the Amis blog by Marco Gralike titled
Just before X-mas about his recent attendance of a Chris Date seminar. Marco talks a lot about the supposed trust of the data that you (a user or a developer or whatever) reads from the database. He also goes on to emphasise the issues of security and security issues in the database and also the complexity of modern implementations that actually make it harder to make a database secure due to the huge code paths between the user and the data.
It does seem that security is a core theme in relational databases and for me in Oracle in particular. Security is one of the core tasks of a modern Oracle DBA and needs to be considered at all levels. It is very interesting to read this post and realise how deep security goes in the database world.