Database Technology

FIT9019: Week 5

Database Design III – Boyce Codd Normal Form, presented by Manoj Kathpalia, alerted me to the value of revising the text book. It seems I do not have a clear grasp of some of the characteristics of each Normal form. Must ensure to remember that for a relation to be in BCNF every functional dependency must be a candidate key, this is best illustrated graphically:

source: Database Systems, Cornell and Rob, 2009

So, although the iPhone pic of the text book is a bit blurry, it can be seen that a sneaky dependency from a non-candidate key attribute to another attribute will cause update anomalies and refrain the table from achieving BCNF.

Most of the lecture was focused on ensuring that everyone understood the process of 1NF -> 2NF -> 3NF -> BCNF. I have already made a detailed post on this process which can be viewed here.

Our tutorial was 2 hours of toying with MicroSoft Access. I came into it with an open attitude, but after about 90 minutes I was lost in the world of GUI fluff that is Access. I am sure that with time it is something that one could learn to use with more efficiency, but with superior performing Open Source alternatives (ie: LAMP bundle) I cannot ever see myself working on an Access database by choice.

Pearl of the Week: Avoid Microsoft Access.

I plan to review the text book over the next week to ensure that my current perception of each aspect of the subject is in fact valid. Particularly important is to rote learn definitions for 1NF, 2NF, 3NF, BCNF, Functional Dependency, Transitive Key Dependency(3NF), Partial Dependency (2NF) and Non-Key Partial Dependencies (BCNF).

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