# Back to Basics

• Comments posted to this topic are about the item Back to Basics

• I've found learning about the mathematical background to the relational model very enlightening.

Some programmers and DBA seem to panic when I mention the "M" word, but the mathematics behind the relational model is actually very easy to understand. Most people know something about set theory. Mentioning  predicate logic makes some people think they are going to have to start doing proofs - but all you need to know is how the methods of describing and manipulating data in the relational model are derived from predicate logic.

I recommend  by "Applied Mathematics for Database Professionals" by Lex de Haan and Toon Koppelaars as a starting point. The book starts with a very clear explanation of the mathematics (my degree is in English Language and Literature and I had no trouble understanding it!), then explains how they apply to the relational model and then continues through to a real database based on these principles. The database happens to be an Oracle one but the principles apply in exactly the same manner to all RDBMSs.

• I agree that knowing the basics is very important. Recently I interviewed with a company I had hoped to get into. I didn't get past the first interview. Upon hearing back from the interviewers, they basically said they felt I was lacking in some of the fundamentals. In this case the fundamentals aren't exactly "basic", but they are important concepts to have down. They answer I gave were correct, but not elegant.

Not getting that position was a real blow to me. I've embarked on filling in gaps in my skills.

Kindest Regards, Rod Connect with me on LinkedIn.

• They answer I gave were correct, but not elegant.

Sometimes there is a difference between the right answer and the right answer for the interview. You have to know both and try to work out which answer the interviewer is expecting.

Consider this question from the Oracle SQL Fundamentals Exam Guide

4. An entity-relationalship diagram shows data modelled into

A. Two-dimensional tables

B. Multidimensional tables

C. Hierarchical tables

D. Object-oriented structures.

The correct answer is B (which you will know if you have understood relational theory properly) the answer Oracle want to A, which is definitely wrong, but right if you want to pass the Oracle SQL Fundamentals Exam.

I don't know if Oracle have fixed this rather fundamental bug in their training material yet, but it's a bit of a showstopper.

• In a less academic way, I've noticed that a lot of younger professionals have very little understanding of the Windows command prompt (or DOS prompt, as I still say). Even though I spend less and less time in the command prompt these days, I was perplexed as to why even the really talented young people I work with have such little experience with it. But it makes sense that since there is no dependency on it these days, that knowledge is being lost. It's not a necessity to know how to use the command prompt these days, but it can save time in a pinch. However, the time savings trade-off may not be worth the learning curve for younger technologists.

• bperry's comment made me smile. My son, a few years ago, had an issue with his laptop. We had to go into the cli to restore things and I was surprised when I asked him to create a directory and he said "how?". We had a nice DOS/bash lesson that day.

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