Re: table design

I did all of the initial design work with a pencil and paper, as I found it was the most efficient way.  Along the way I figured out that you guys are right, related tables are what I need.  I drew up all the relationships I wanted and laid the db out the best that I could and have started to code it.  I have a good amount of test data in text files I will copy in and then I am going to start running queries against it and see how it holds up and what needs to be fixed.

You are right though about a place to start.  There is no *simple* tutorial or book out there on this subject.  There are plenty of books on starting with SQL and Postgres but none on how to design a database.  The ones I have found explain a lot of design ideas but are heavy in Math and then fail to implement them or they implement good ideas without explaining why they are doing it.

I have a few books and have been slowly making my way through them and the combination of them and trial and error to see what works and what doesn't has proved to be the best way.  The ones I found helpful for me anyway are "SQL and Relational Theory" by CJ Date, The Postgres Documentation, and "The Theory Of Relational Databases" David Maier.

I am still having a few small issues getting ON DELETE CASCADE and ON UPDATE CASCADE to work but I will figure it out soon enough.  Thanks for the thoughts and suggestions on the books, they were worth the money. 

On Sat, Feb 12, 2011 at 6:50 PM, Craig Barnes <cjbarnes18@gmail.com> wrote:

On 11 February 2011 17:08, Brent Dombrowski <brent.dombrowski@gmail.com> wrote:

On Feb 8, 2011, at 12:04 PM, matty jones wrote:

> I may be over-thinking this but I have some questions about table design.
> The purpose of the database will be to catalog a comic book collection.  I
> have been reading the online manual along with a few other books to give
> myself some ideas of how I want to lay the database out.  The problem that I
> am running into is that I have the following tables that inherit from other
> tables.
>
>
> CREATE TABLE BookTitle(
>
> booktitle      text,
> compilation    text
> ) INHERITS (SeriesTitle, Storyline, BookCover, ISBN, I_Date, Price, Style,
> StoryTitle);
>
> CREATE TABLE StoryTitle(
>
> storytitle_id int,
> storytitle text
> ) INHERITS (Characters, Writer, Artist, CoverArtist, Letters, Ink, Pencils,
> Colors, Notes);
>
>
> I am using inheritance to get the table structure from other tables.  I am
> trying to limit the amount of information in each table, as I *believe* this
> will help keep the table normalized.  My question is, is this necessary?  Is
> there a way to just have all separate tables and link certain columns
> together so the same string shows up in each and if I update one column it
> will propagate to other linked columns?  That would be my ideal situation.
> I have all the tables coded in a SQL file how I believe they should be
> setup but it is 120 lines and didn't think it was necessary to post the
> whole thing.  My reason for doing this was because each BookTitle contains
> multiple StoryTitles and each StoryTitle contains an artist, writer, etc...
> Not every BookTitle though will contain Pencils, CoverArtist, etc.  My line
> of thinking was to create the structure like this so that when I input
> the information into a table like so
>
> INSERT INTO booktitle (booktitle, i_date, storytitle, name, writer, artist,
> coverartist, seriestitle)
> VALUES ('Batman #14', 'Dec 42 - Jan 43', 'The Case Batman Failed To Solve',
> 'Batman, Bruce Wayne, Dick Greyson, Robin', 'Don Cameron', 'Jerry Robinson',
> 'Jerry Robinson', 'Batman');
>
> It is entered into a single row. but if I were to have the separate tables
> without inheritance, I am not sure how I would be able to relate one Artist
> to a particular StoryTitle.  I understand the basics about joins and keys
> but I don't think keys are what I need here and joins are what I am using to
> output the information I want or is that redundant due to inheritance.
> Right now I will be the only one using this database but I want to design
> it correctly so that if others want to use it, they can just copy my code
> and have a properly designed database.  The final goal is to use PHP/XHTML
> to send the query outputs to the browser for the user to view.  Most of the
> cataloging programs are stand-alone platform specific or they are expensive
> service-based and charge a fee.  I want a program I can access from any
> modern web browser that is free, and can be custom modified, and I need to
> learn PG for my job so this is a welcome project.  I am using Bento on my
> Mac right now but I can't use it at work(Win7) or on my other
> computers(Linux) so that won't work and I am sure I am not the only person
> who would like a full featured cataloging program that is run through the
> browser.
>
> Any thoughts or further reading ideas are greatly welcome.
>
> Thanks
>
> Matty

I don't think inheritance is going to help you here. The insert statement you have will not work. You can only insert booktitle and compilation into booktitle. You can't insert into the inherited fields. "Inheritance does not automatically propagate data from INSERT or COPY commands to other tables in the inheritance hierarchy." as per the Postgres Manual.

I think you need to look into dependencies, normal forms, and lossless joins. I can't think of any references off the top of my head. Hopefully, someone can chime in with some recommendations. Setting up the tables is more of a pencil and paper exercise for me. I find it to be something of a voodoo art as well.

Brent.

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Hi Matty,

I would agree with Brent in that inheritance isn't going to help you much in what you are trying to achieve.   Based on what I can gleam from your description related tables are what you need.

I am also not aware of one great place for you to start. I had a scan of Wikipedia, but alas nothing much for the beginner db designer.

I sometimes use a diagram tool to help visualise the data structure (dia, vue) especially where complex data structures are needed.

If you like, send in your SQL (or put it in pastebin) and we could start playing with table design ideas.

Hope this helps.

Craig