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Understanding Dependencies and Normalization


#1

Hello. I have done a database. and I must write the following for a report. Could someone explain to me the difference in dependencies and normalization? I really don't understand the terms.


#2

This looks like homework or an interview question. If it's homework, you need to -- well -- do your homework! If it's an interview question, you might need some additional training to qualify for the job.

Also, if you just google the terms, you'll get a wealth of information. e.g. I just googled "define functional dependency in rdbms" and got:

In relational database theory, a functional dependency is a constraint between two sets of attributes in a relation from a database.


#4

Well, that's a question to as your business sponsor. Common sense helps a bit. An edition has a certain publication date, but some date may have many publications


#5

Ooh, BCNF. That's a step beyond 3NF, and it's like a table multiplier. I can practically guarantee that 7 tables is not enough just based on general knowledge of Boyce-Codd :-).


#6

I thought that a non-trivial dependency was if Y was not a subset of X, Isn't that I have?
Am I right so far? I thought I had to write ISBN, edition together at all times since they are both primary keys in the table and are paired together....so why would like something like X: edition and Y: published date.


#7

What you explain why not? I don't get the concept. I was going through this....but I still don't get it: http://www.vertabelo.com/blog/technical-articles/boyce-codd-normal-form-bcnf


#8

We now have to report you to your school for plagiarism and get you expelled:frowning:.