Do you link in your book SQL to Relational Algebra and/or Relational Calculus? Do you think it is important to understand those 2 topics in order to better grasp SQL?

Also, one of the operators of Relational Algebra, namely 'divideby', has not been implemented in SQL. Do you think it should be?

Thank you,

Mihai Fonoage

[ October 16, 2007: Message edited by: Mihai Fonoage ]

Lynn Beighley<br />Author, Head First SQL

Originally posted by Mihai Fonoage:

Do you link in your book SQL to Relational Algebra and/or Relational Calculus? Do you think it is important to understand those 2 topics in order to better grasp SQL?

Another opinion on this: Personally, no. I did learn relational algebra and calculus in my db class. I learned SQL before that and find it perfectly possible to master without the theoretical basis.

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Another opinion on this: Personally, no. I did learn relational algebra and calculus in my db class. I learned SQL before that and find it perfectly possible to master without the theoretical basis.

It would be interesting to hear from a person who was introduced to Relational Algebra first, then to SQL. I am not that person since I was exposed to SQL first also. I believe that if one knows Relational Algebra, it would be easier to learn SQL.

Mihai Fonoage

[ October 17, 2007: Message edited by: Mihai Fonoage ]

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In college we had the couse of RDBMS in one of the semesters and the firt couple of chapters were relational algebra, set theory, that made the concepts a lil easier, but I can't really say becos people without theory also seem to understand and implement really well.

I'm not saying you can't learn/understand SQL if you don't know relational algebra, of course, I'm saying that I believe it is easier to learn and understand SQL if you do, since the operators part of the relational model where based on Relational Algebra.

Mihai Fonoage

Originally posted by Mihai Fonoage:

I'm saying that I believe it is easier to learn and understand SQL if you do, since the operators part of the relational model where based on Relational Algebra.

That's true. Of course, it is also easier to learn and understand relational algebra if you already know SQL. It's usual for the second similar thing you learn to be easier.

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Originally posted by Jeanne Boyarsky:

That's true. Of course, it is also easier to learn and understand relational algebra if you already know SQL. It's usual for the second similar thing you learn to be easier.

You are right, and it makes sense to be like this. Another example is C++ and Java. I also see this as more of a background problem: what is the necessary background one should have in order to better, and more faster, understand the new 'concepts'.

Mihai Fonoage

Not shure. Does one need to know c++ to be a good Java programmer? I would say no.Originally posted by Mihai Fonoage:

You are right, and it makes sense to be like this. Another example is C++ and Java. I also see this as more of a background problem: what is the necessary background one should have in order to better, and more faster, understand the new 'concepts'.

Mihai Fonoage

It's accademicaly sound to learn the relational theory before learning sql. That's how they teached it to me at school too.

But I think you can learn sql very well without knowing the relational thingies up front. You 'll get the skills on the fly.

I only became good in sql after school, when I had to use it professionaly.

Regards, Jan

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Originally posted by Jan Cumps:

Not shure. Does one need to know c++ to be a good Java programmer? I would say no.

It's accademicaly sound to learn the relational theory before learning sql. That's how they teached it to me at school too.

But I think you can learn sql very well without knowing the relational thingies up front. You 'll get the skills on the fly.

I only became good in sql after school, when I had to use it professionaly.

Regards, Jan

No, but one that knows C++ and Java has an advantage over one that only knows one of them, and this is mainly because you know have an option to choose how to solve a particular problem, in C++ or Java. Is it easier to learn Java if you already know C++? Definitely. Is it impossible to learn Java if you don't know C++? Of course not. And the same goes for SQL and Relational Algebra.

Mihai Fonoage

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