Archive for November, 2012

database musings (“deep thoughts”)

November 18, 2012

I have a soft spot for hierarchical databases.  My first database-related job was programming in M/Mumps.  I know the standard history of databases says that hierarchical databases are a relic of the past, and that, thanks to Codd, relational databases solve many of the problems of hierarchical (and other kinds of) databases.  I like relational databases – I was an Oracle DBA, I’ve worked with DB2, Sybase, Postgres, mSQL, others, and now MySQL.  I really like InnoDB.  However, I am occasionally sad that hierachical databases seem a thing of the past.
Or are they?  Yesterday I had a thought that hierarchical databases are much more widely used than relational databases.  In fact, maybe every single computer has a hierarchical database that is used by every computer user, whether they have database software installed or not.  The file system!  Isn’t that a hierarchical database?  The idea made me feel better.  🙂


MySQL for Beginners Training on Demand course, Day 2

November 1, 2012

It’s been a while since my post on taking day 1 of this course; as promised, here are my notes and observations after taking Day 2.

First, this is one of the nice things about taking Training on Demand.  I could take Day 1, go about my other business, apply what I learned, etc, then, when ready, take Day 2, even a month or so later!  I was able to go back and review Day 1, then move on to Day 2, entirely at my own schedule.

I remembered something from earlier, and wanted to find it again, so I tried out the search capabilities.  I searched for the phrase I wanted, and up came links to the lessons it appeared in.  I could click on any of the results to view that lesson, and watch, or check the captioning to find the phrase I was looking for.  It worked perfectly!

Day 2 covers data types, basic SELECT queries, and how to create and maintain tables and databases (using DROP and ALTER, and how they work).  Again, I enjoy reviewing this kind of material.  And if it’s new, it will give you plenty to chew on and try out.

In my case, the discussion of data types sent me off on a tangent of my own, about floating-point data and rounding errors.  I was able to google and research, then get back to the course when I was done.  (By the way, I found a good link on the subject at at – “What Every Computer Scientist Should Know About Floating-Point Arithmetic” – in case you’re interested.)  So, again, that’s a nice thing about Training on Demand – you can start, stop, go off on tangents, and resume when ready.

Activities in Training on Demand include quizzes to test your knowledge (with answers in the back of the activity guide, or given by the instructor in a separate video segment for each activity).

In summary, I enjoyed Day 2, and look forward to Days 3 and 4, and the bonus material.  Stay tuned!